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2020 Volume 31 Issue 12
2020, 31(12): 2989-2990
doi: 10.1016/j.cclet.2020.03.034
Abstract:
The recent molecular iodine catalyzed [1, 2]-rearrangement of aryl amines and 3-amino-1H-indazolesfor the synthesis of 1, 2, 3-benzotriazines is highlighted.
The recent molecular iodine catalyzed [1, 2]-rearrangement of aryl amines and 3-amino-1H-indazolesfor the synthesis of 1, 2, 3-benzotriazines is highlighted.
2020, 31(12): 2991-2992
doi: 10.1016/j.cclet.2020.03.030
Abstract:
The recent development of selective oxidation of aromatic sulfides with molecular oxygen was highlighted. The sulfoxides and sulfones could be obtained by simply switching the reaction media, i.e., bis(2-butoxyethyl)ether (BBE) or poly(ethylene glycol)dimethyl ether (PEGDME). The application of the high-boiling-point polyether as an initiator and green media can eliminate the need of large quantities of additives and volatile solvents. This strategy represents an economic and eco-friendly method that could find potential applications.
The recent development of selective oxidation of aromatic sulfides with molecular oxygen was highlighted. The sulfoxides and sulfones could be obtained by simply switching the reaction media, i.e., bis(2-butoxyethyl)ether (BBE) or poly(ethylene glycol)dimethyl ether (PEGDME). The application of the high-boiling-point polyether as an initiator and green media can eliminate the need of large quantities of additives and volatile solvents. This strategy represents an economic and eco-friendly method that could find potential applications.
2020, 31(12): 2993-2995
doi: 10.1016/j.cclet.2020.06.034
Abstract:
The deconstructive reorganization strategy for the synthesis of benzene-containing products from the kojic acid- and maltol-derived alkynes has been recently reported. In this strategy, kojic acid and maltol are analogous to the "Transformers", which can transform into benzofurans and benzaldehydes via annulation reactions. Under the synthetic standpoint, this deconstructive reorganization strategy features high atom economy, innate scalability and functional group tolerance. In the near future, we believe that this unique method will be widely investigated and other novel transformations of kojic acid and maltol will be discovered.
The deconstructive reorganization strategy for the synthesis of benzene-containing products from the kojic acid- and maltol-derived alkynes has been recently reported. In this strategy, kojic acid and maltol are analogous to the "Transformers", which can transform into benzofurans and benzaldehydes via annulation reactions. Under the synthetic standpoint, this deconstructive reorganization strategy features high atom economy, innate scalability and functional group tolerance. In the near future, we believe that this unique method will be widely investigated and other novel transformations of kojic acid and maltol will be discovered.
2020, 31(12): 2996-2998
doi: 10.1016/j.cclet.2020.08.037
Abstract:
Generation of 3-sulfonated 2H-pyrrol-2-ones through a three-component reaction of allenoic amides, sulfur dioxide, and aryldiazonium tetrafluoroborates under metal-free conditions is achieved. This transformation proceeds under mild conditions without the addition of catalysts or additives, giving rise to 3-sulfonated 2H-pyrrol-2-ones in moderate to good yields. Good functional group compatibility is observed. A plausible mechanism is proposed, which is initiated by aryl radicals formed in situ from aryldiazonium tetrafluoroborates and DABCO·(SO2)2. Additionally, excellent chemoselectivity and regioselectivity are presented in this transformation.
Generation of 3-sulfonated 2H-pyrrol-2-ones through a three-component reaction of allenoic amides, sulfur dioxide, and aryldiazonium tetrafluoroborates under metal-free conditions is achieved. This transformation proceeds under mild conditions without the addition of catalysts or additives, giving rise to 3-sulfonated 2H-pyrrol-2-ones in moderate to good yields. Good functional group compatibility is observed. A plausible mechanism is proposed, which is initiated by aryl radicals formed in situ from aryldiazonium tetrafluoroborates and DABCO·(SO2)2. Additionally, excellent chemoselectivity and regioselectivity are presented in this transformation.
2020, 31(12): 2999-3000
doi: 10.1016/j.cclet.2020.09.005
Abstract:
The recent development of microwave-assisted aqueous synthesis of polyheterocyclic-fused quinoline-2-thiones through 6π-electrocyclization was highlighted.
The recent development of microwave-assisted aqueous synthesis of polyheterocyclic-fused quinoline-2-thiones through 6π-electrocyclization was highlighted.
2020, 31(12): 3001-3014
doi: 10.1016/j.cclet.2020.04.029
Abstract:
Polypeptides are one kind of promising biodegradable and biocompatible biomedical polymers with the structural units of various α-amino acids. Polypeptides were first polymerized by the ring-opening polymerization (ROP) of α-amino acid N-carboxyanhydrides (NCAs) by Leuchs and Hermann in 1906. In the past decades, several effective strategies, including the selection of initiators, the adjustment of reaction conditions, and the introduction of catalysts, have been reported to improve the controllability of the ROP of various α-amino acid NCAs to synthesize different polypeptides with precise chemical structures and low polydispersity indexes. In this Review, the strategies, mechanisms, challenges, and opportunities for controlled synthesis of polypeptides by the ROP of different α-amino acid NCAs have been declared.
Polypeptides are one kind of promising biodegradable and biocompatible biomedical polymers with the structural units of various α-amino acids. Polypeptides were first polymerized by the ring-opening polymerization (ROP) of α-amino acid N-carboxyanhydrides (NCAs) by Leuchs and Hermann in 1906. In the past decades, several effective strategies, including the selection of initiators, the adjustment of reaction conditions, and the introduction of catalysts, have been reported to improve the controllability of the ROP of various α-amino acid NCAs to synthesize different polypeptides with precise chemical structures and low polydispersity indexes. In this Review, the strategies, mechanisms, challenges, and opportunities for controlled synthesis of polypeptides by the ROP of different α-amino acid NCAs have been declared.
2020, 31(12): 3015-3026
doi: 10.1016/j.cclet.2020.05.003
Abstract:
Multifunctional bismuth sulfide (Bi2S3) nanomaterials exhibit significant potential as nanomedicines for the diagnosis and treatment of cancer. These nanomaterials act as excellent photothermal agents and radiation sensitizers for the treatment of tumors, and they can also act as contrast agents for computed tomography (CT) imaging, photoacoustic imaging (PA), and other forms of imaging to provide real-time tumor monitoring and testing guidance. Compared with other nanomaterials, Bi2S3 nanomaterials can readily adapt to different applications by virtue of the fact that they can be easily functionalized. However, these nanomaterials have some limitations that cannot be ignored and need to be addressed, such as poor biocompatibility, toxicity, and low chemical stability. It is widely believed that appropriate functionalization of Bi2S3 nanomaterials could remedy such defects and significantly improve performance. This review summarizes the ways in which Bi2S3 nanomaterials can be functionalized and discusses their applications in cancer theranostics over the last few years, focusing particularly on imaging and therapy. We also discuss issues relating to how Bi2S3 nanomaterials can be analyzed, including how we might be able to use these systems to inhibit and treat tumors and how current limitations might be overcome to improve treatment efficacy. Finally, we hope to provide inspiration and guidance as to how we might create a more optimized multifunctional nano-system for the diagnosis and treatment of tumors.
Multifunctional bismuth sulfide (Bi2S3) nanomaterials exhibit significant potential as nanomedicines for the diagnosis and treatment of cancer. These nanomaterials act as excellent photothermal agents and radiation sensitizers for the treatment of tumors, and they can also act as contrast agents for computed tomography (CT) imaging, photoacoustic imaging (PA), and other forms of imaging to provide real-time tumor monitoring and testing guidance. Compared with other nanomaterials, Bi2S3 nanomaterials can readily adapt to different applications by virtue of the fact that they can be easily functionalized. However, these nanomaterials have some limitations that cannot be ignored and need to be addressed, such as poor biocompatibility, toxicity, and low chemical stability. It is widely believed that appropriate functionalization of Bi2S3 nanomaterials could remedy such defects and significantly improve performance. This review summarizes the ways in which Bi2S3 nanomaterials can be functionalized and discusses their applications in cancer theranostics over the last few years, focusing particularly on imaging and therapy. We also discuss issues relating to how Bi2S3 nanomaterials can be analyzed, including how we might be able to use these systems to inhibit and treat tumors and how current limitations might be overcome to improve treatment efficacy. Finally, we hope to provide inspiration and guidance as to how we might create a more optimized multifunctional nano-system for the diagnosis and treatment of tumors.
2020, 31(12): 3027-3040
doi: 10.1016/j.cclet.2020.05.027
Abstract:
The tumor microenvironment (TME) significantly influences cancer evolution and therapeutic efficacy. Targeting biofunctional molecules to the TME has long been appreciated as a means of raising local drug concentrations and reducing systemic toxicities. The booming nanotechnology field has realized the importance of cathepsin B to derive a variety of intelligent enzyme-responsive nanosized drug delivery systems (nanoDDS) to improve treatment responses and clinical outcomes. In this tutorial review, after introducing the molecular structure and physiological/pathological functions of cathepsin B, the outstanding achievements of cathepsin B-responsive nanoplatforms in the precise diagnosis, targeted therapy, and synergistic theranostics of malignant tumors are systematically described. Finally, the challenges of enzyme-substrate incompatibility, low diagnostic sensitivity, mass production and biocompatibility of multifunctional nanoDDS are considered in order to successfully promote them to clinical applications.
The tumor microenvironment (TME) significantly influences cancer evolution and therapeutic efficacy. Targeting biofunctional molecules to the TME has long been appreciated as a means of raising local drug concentrations and reducing systemic toxicities. The booming nanotechnology field has realized the importance of cathepsin B to derive a variety of intelligent enzyme-responsive nanosized drug delivery systems (nanoDDS) to improve treatment responses and clinical outcomes. In this tutorial review, after introducing the molecular structure and physiological/pathological functions of cathepsin B, the outstanding achievements of cathepsin B-responsive nanoplatforms in the precise diagnosis, targeted therapy, and synergistic theranostics of malignant tumors are systematically described. Finally, the challenges of enzyme-substrate incompatibility, low diagnostic sensitivity, mass production and biocompatibility of multifunctional nanoDDS are considered in order to successfully promote them to clinical applications.
2020, 31(12): 3041-3046
doi: 10.1016/j.cclet.2020.07.030
Abstract:
Magnetic nanoparticles (MNPs) have become a research hotspot and widely used in the biomedical field in recent decades due to their unique magnetic properties. This minireview summarizes the specific gene transfection of magnetic particles (magnetofection) during eversy dynamic process of gene delivery (gene binding, cellular uptake, endosomal escape, intracellular trafficking and in vivo targeting). Meanwhile, the synergistic biomedical application of magnetofection and the effects of MNPs have also been discussed, including magnetic resonance imaging (MRI), magnetic mediated hyperthermia (MMH), Fenton reaction and autophagy. Finally, the clinical prospect of magnetofection was briefly expected.
Magnetic nanoparticles (MNPs) have become a research hotspot and widely used in the biomedical field in recent decades due to their unique magnetic properties. This minireview summarizes the specific gene transfection of magnetic particles (magnetofection) during eversy dynamic process of gene delivery (gene binding, cellular uptake, endosomal escape, intracellular trafficking and in vivo targeting). Meanwhile, the synergistic biomedical application of magnetofection and the effects of MNPs have also been discussed, including magnetic resonance imaging (MRI), magnetic mediated hyperthermia (MMH), Fenton reaction and autophagy. Finally, the clinical prospect of magnetofection was briefly expected.
2020, 31(12): 3047-3054
doi: 10.1016/j.cclet.2020.07.048
Abstract:
As a class of metal-free two-dimensional (2D) semiconductor materials, polymeric carbon nitrides have attracted wide attention recently due to its facile regulation of the molecular and electronic structures, availability in abundance and high stability. According to the different ratios of C and N atoms in the framework, a series of CxNy materials have been successfully synthesized by virtue of various precursors, which further triggers extensive investigations of broad applications ranging from sustainable photocatalytic reactions and highly sensitive optoelectronic biosensing. In view of topological structures on their electronic structures and material properties, the as-reported CxNy could be generally classified into two main categories with three- or six-bond-extending frameworks. Owing to the effective n→π* transition in most CxNy materials, the relative energy level of the lone-pair electrons on N atoms is high, which thus endows the materials with the capability of visible light absorption. Meanwhile, the different repeating units, bridging groups and defect sites of these two kinds of CxNy allow them to effectively drive a diverse of promising applications that require specific electronic, interfacial and geometric properties. This review paper aims to summarize the recent progress in topological structure design and the relevant electronic band structures and striking properties of CxNy materials. In the final part, we also discuss the existing challenges of CxNy and outlook the prospect possibilities.
As a class of metal-free two-dimensional (2D) semiconductor materials, polymeric carbon nitrides have attracted wide attention recently due to its facile regulation of the molecular and electronic structures, availability in abundance and high stability. According to the different ratios of C and N atoms in the framework, a series of CxNy materials have been successfully synthesized by virtue of various precursors, which further triggers extensive investigations of broad applications ranging from sustainable photocatalytic reactions and highly sensitive optoelectronic biosensing. In view of topological structures on their electronic structures and material properties, the as-reported CxNy could be generally classified into two main categories with three- or six-bond-extending frameworks. Owing to the effective n→π* transition in most CxNy materials, the relative energy level of the lone-pair electrons on N atoms is high, which thus endows the materials with the capability of visible light absorption. Meanwhile, the different repeating units, bridging groups and defect sites of these two kinds of CxNy allow them to effectively drive a diverse of promising applications that require specific electronic, interfacial and geometric properties. This review paper aims to summarize the recent progress in topological structure design and the relevant electronic band structures and striking properties of CxNy materials. In the final part, we also discuss the existing challenges of CxNy and outlook the prospect possibilities.
2020, 31(12): 3055-3064
doi: 10.1016/j.cclet.2020.05.016
Abstract:
Hybrid organic-inorganic perovskite materials have attracted significant attention of most researchers in recently years, which is ascribed to the superior photoelectric properties, such as the suitable band gaps for harvesting sunlight, and exhibit high optical adsorption, high charge-carrier lifetimes and long diffusion lengths. The photodetectors, light-emitting diodes, solar cells and photocatalysts represent the remarkable applications for the hybrid organic-inorganic perovskite materials. Herein, we review the recent progress of hybrid organic-inorganic perovskite-based photodetectors, light-emitting diodes, solar cells and photocatalysts. The challenges and outlook for the hybrid organic-inorganic perovskite-based photodetectors, light-emitting diodes, solar cells and photocatalysts are considered.
Hybrid organic-inorganic perovskite materials have attracted significant attention of most researchers in recently years, which is ascribed to the superior photoelectric properties, such as the suitable band gaps for harvesting sunlight, and exhibit high optical adsorption, high charge-carrier lifetimes and long diffusion lengths. The photodetectors, light-emitting diodes, solar cells and photocatalysts represent the remarkable applications for the hybrid organic-inorganic perovskite materials. Herein, we review the recent progress of hybrid organic-inorganic perovskite-based photodetectors, light-emitting diodes, solar cells and photocatalysts. The challenges and outlook for the hybrid organic-inorganic perovskite-based photodetectors, light-emitting diodes, solar cells and photocatalysts are considered.
2020, 31(12): 3065-3072
doi: 10.1016/j.cclet.2020.04.023
Abstract:
As a highly strained small molecule, [1.1.1]propellane has been widely used in various synthetic transformations owing to the exceptional reactivity of the central bond between the two bridgehead carbons. Utilizing strain-release approaches, the rapid development of strategies for the construction of bicyclo[1.1.1]pentane (BCP) and cyclobutane derivatives using [1.1.1]propellane as the starting material has been witnessed in the past few years. In this review, we highlight the most recent advances in this field. Accordingly, the reactivity of [1.1.1]propellane can be divided into three pathways, including radical, anionic and transition metal-catalyzed pathways under appropriate conditions.
As a highly strained small molecule, [1.1.1]propellane has been widely used in various synthetic transformations owing to the exceptional reactivity of the central bond between the two bridgehead carbons. Utilizing strain-release approaches, the rapid development of strategies for the construction of bicyclo[1.1.1]pentane (BCP) and cyclobutane derivatives using [1.1.1]propellane as the starting material has been witnessed in the past few years. In this review, we highlight the most recent advances in this field. Accordingly, the reactivity of [1.1.1]propellane can be divided into three pathways, including radical, anionic and transition metal-catalyzed pathways under appropriate conditions.
2020, 31(12): 3073-3082
doi: 10.1016/j.cclet.2020.07.042
Abstract:
Chromone and flavone are both central backbones of natural products and clinical medicines. Synthesis of diversely functionalized chromones and flavones constitutes significant research contents of the modern synthetic science because abundant molecular libraries of such types are crucial in providing candidate compounds for the discovery of new pharmaceuticals and functional materials. The direct C-H bond activation or functionalization on these heterocyclic backbones provides highly powerful tools for the rapid accesses to densely functionalized chromone and flavone derivatives. Considering the importance of the functionalized chromone and flavone compounds as well as the notable advances in the synthesis of such products by direct C-H activation or functionalization, we review herein the research advances in the C-H bond activation and functionalization reactions of chromone and flavones, in hope of showing the current states and promise of the research domain.
Chromone and flavone are both central backbones of natural products and clinical medicines. Synthesis of diversely functionalized chromones and flavones constitutes significant research contents of the modern synthetic science because abundant molecular libraries of such types are crucial in providing candidate compounds for the discovery of new pharmaceuticals and functional materials. The direct C-H bond activation or functionalization on these heterocyclic backbones provides highly powerful tools for the rapid accesses to densely functionalized chromone and flavone derivatives. Considering the importance of the functionalized chromone and flavone compounds as well as the notable advances in the synthesis of such products by direct C-H activation or functionalization, we review herein the research advances in the C-H bond activation and functionalization reactions of chromone and flavones, in hope of showing the current states and promise of the research domain.
2020, 31(12): 3083-3094
doi: 10.1016/j.cclet.2020.07.035
Abstract:
Nitriles are widely existed in many bioactive compounds, and they can be easily transformed into other functional groups. Therefore, the synthesis of nitriles under cyanide-free conditions is of significant importance. Recent advances for the synthesis of nitriles through photoinduced C-C bond cleavage of cycloketone oximes classified by the type of C-X bond forming are summarized. Various compounds possessing nitriles can be efficiently accessed via this method.
Nitriles are widely existed in many bioactive compounds, and they can be easily transformed into other functional groups. Therefore, the synthesis of nitriles under cyanide-free conditions is of significant importance. Recent advances for the synthesis of nitriles through photoinduced C-C bond cleavage of cycloketone oximes classified by the type of C-X bond forming are summarized. Various compounds possessing nitriles can be efficiently accessed via this method.
2020, 31(12): 3095-3101
doi: 10.1016/j.cclet.2020.06.041
Abstract:
The two-dimensional surfaces have been fueled by the infinite possibility they offered for basic research, and for novel technologies in nanoelectronics. To realize many of these promises, the effective strategies were to design and control their surface chemistry, which plays a vital role in determining the chemical and physical properties. Macrocyclic host-guest chemistry with the reversible noncovalent interactions between macrocyclic hosts and suitable guests can be readily used for constructing multifunctional surfaces. Macrocyclic pillararenes, possessed the unique structure, have attracted the attentions of researchers in recent years. This feature article covers the recent development of pillararene-based two-dimensional interfaces, including the fabrication and function of the hybrid composite. The combination of pillararenes and materials platform exhibited the novel property because of the characteristic of cavity of macrocyclic host and confined spaces of surfaces. We anticipate that this review will be helpful to the researchers working in the fields of supramolecular chemistry and materials science.
The two-dimensional surfaces have been fueled by the infinite possibility they offered for basic research, and for novel technologies in nanoelectronics. To realize many of these promises, the effective strategies were to design and control their surface chemistry, which plays a vital role in determining the chemical and physical properties. Macrocyclic host-guest chemistry with the reversible noncovalent interactions between macrocyclic hosts and suitable guests can be readily used for constructing multifunctional surfaces. Macrocyclic pillararenes, possessed the unique structure, have attracted the attentions of researchers in recent years. This feature article covers the recent development of pillararene-based two-dimensional interfaces, including the fabrication and function of the hybrid composite. The combination of pillararenes and materials platform exhibited the novel property because of the characteristic of cavity of macrocyclic host and confined spaces of surfaces. We anticipate that this review will be helpful to the researchers working in the fields of supramolecular chemistry and materials science.
2020, 31(12): 3102-3106
doi: 10.1016/j.cclet.2020.03.039
Abstract:
Drug-loaded micelles for oral administration are desired for its convenience, low cost and flexibility, but current designs rely on introducing pH responsiveness, leaving problems like drug leakage and low accuracy of targeted delivery un-solved. Herein, we reported an acid-resistant ROS-responsive hyperbranched polythioether which can self-assemble into micellar structure and pass through the gastrointestinal tract without leaking drugs. At the inflammatory lesions, the thioester bonds are oxidized to sulphone groups to significantly increase the hydrophilicity in response to accumulated ROS species and efficiently release the encapsulated drugs. Animal experiments, including the evaluation of bodyweight, colon length, MPO activity, spleen index, histology and quantitative reverse transcription PCR, evidenced that the drug-loaded micelles have improved therapeutic efficiency compared to bare drug administration for the treatment of DSS-induced colitis in mice. This study provides an example of oral administrated micellar system can be extended for the treatment of other intestinal tract diseases.
Drug-loaded micelles for oral administration are desired for its convenience, low cost and flexibility, but current designs rely on introducing pH responsiveness, leaving problems like drug leakage and low accuracy of targeted delivery un-solved. Herein, we reported an acid-resistant ROS-responsive hyperbranched polythioether which can self-assemble into micellar structure and pass through the gastrointestinal tract without leaking drugs. At the inflammatory lesions, the thioester bonds are oxidized to sulphone groups to significantly increase the hydrophilicity in response to accumulated ROS species and efficiently release the encapsulated drugs. Animal experiments, including the evaluation of bodyweight, colon length, MPO activity, spleen index, histology and quantitative reverse transcription PCR, evidenced that the drug-loaded micelles have improved therapeutic efficiency compared to bare drug administration for the treatment of DSS-induced colitis in mice. This study provides an example of oral administrated micellar system can be extended for the treatment of other intestinal tract diseases.
2020, 31(12): 3107-3112
doi: 10.1016/j.cclet.2020.04.006
Abstract:
Angiogenesis occurs during the process of tumor growth, invasion and metastasis, and is essential for the survival of solid tumors. As an integrin significantly overexpressed in human tumor vascular endothelial cells, αvβ3 is a suitable targeting site for anti-angiogenesis of tumor. We designed and prepared a selfassembling peptide (SAP) with the ability to targeting αvβ3 and self-assembly. SAP formed nanoparticles in solution and transformed into nanofibrous network once specifically binding to integrin αvβ3 on the surface of human umbilical vein endothelial cells (HUVECs). The SAP network stably anchored on HUVECs over 24 h, which consequently resulted in high-efficient inhibition of vascularization. In vitro anti-angiogenesis experiment displayed that the inhibition rate of tube-formation reached 94.9%. In vivo anti-angiogenesis array based on chick chorioallantoic membrane (CAM) model exhibited that the SAP had an inhibition rate up to 63.1%. These results indicated the outstanding anti-angiogenic ability of SAP, potentially for tumor therapy.
Angiogenesis occurs during the process of tumor growth, invasion and metastasis, and is essential for the survival of solid tumors. As an integrin significantly overexpressed in human tumor vascular endothelial cells, αvβ3 is a suitable targeting site for anti-angiogenesis of tumor. We designed and prepared a selfassembling peptide (SAP) with the ability to targeting αvβ3 and self-assembly. SAP formed nanoparticles in solution and transformed into nanofibrous network once specifically binding to integrin αvβ3 on the surface of human umbilical vein endothelial cells (HUVECs). The SAP network stably anchored on HUVECs over 24 h, which consequently resulted in high-efficient inhibition of vascularization. In vitro anti-angiogenesis experiment displayed that the inhibition rate of tube-formation reached 94.9%. In vivo anti-angiogenesis array based on chick chorioallantoic membrane (CAM) model exhibited that the SAP had an inhibition rate up to 63.1%. These results indicated the outstanding anti-angiogenic ability of SAP, potentially for tumor therapy.
2020, 31(12): 3113-3116
doi: 10.1016/j.cclet.2020.04.052
Abstract:
The effect of gold nanoparticle-decorated molybdenum sulfide (AuNP-MoS2) nanocomposites on amyloid-β-40 (Aβ40) aggregation was investigated. The interesting discovery was that the effect of AuNP-MoS2 nanocomposites on Aβ40 aggregation was contradictory. Low concentration of AuNP-MoS2 nanocomposites could enhance the nucleus formation of Aβ40 peptides and accelerate Aβ40 fibrils aggregation. However, although high concentration of AuNP-MoS2 nanocomposites could enhance the nucleus formation of Aβ40 peptides, it eventually inhibited Aβ40 aggregation process. It might be attributed to the interaction between AuNP-MoS2 nanocomposites and Aβ40 peptides. For low concentration of AuNP-MoS2 nanocomposites, it was acted as nuclei, resulting in the acceleration of the nucleation process. However, the structural flexibility of Aβ40 peptides was limited as the concentration of AuNP-MoS2 nanocomposites was increased, resulting in the inhibition of Aβ40 aggregation. These findings suggested that AuNP-MoS2 nanocomposites might have a great potential to design new multifunctional material for future treatment of amyloid-related diseases.
The effect of gold nanoparticle-decorated molybdenum sulfide (AuNP-MoS2) nanocomposites on amyloid-β-40 (Aβ40) aggregation was investigated. The interesting discovery was that the effect of AuNP-MoS2 nanocomposites on Aβ40 aggregation was contradictory. Low concentration of AuNP-MoS2 nanocomposites could enhance the nucleus formation of Aβ40 peptides and accelerate Aβ40 fibrils aggregation. However, although high concentration of AuNP-MoS2 nanocomposites could enhance the nucleus formation of Aβ40 peptides, it eventually inhibited Aβ40 aggregation process. It might be attributed to the interaction between AuNP-MoS2 nanocomposites and Aβ40 peptides. For low concentration of AuNP-MoS2 nanocomposites, it was acted as nuclei, resulting in the acceleration of the nucleation process. However, the structural flexibility of Aβ40 peptides was limited as the concentration of AuNP-MoS2 nanocomposites was increased, resulting in the inhibition of Aβ40 aggregation. These findings suggested that AuNP-MoS2 nanocomposites might have a great potential to design new multifunctional material for future treatment of amyloid-related diseases.
2020, 31(12): 3117-3120
doi: 10.1016/j.cclet.2020.06.024
Abstract:
In this work, polymethacrylic acid (PMAA)-templated silver nanoclusters (Ag NCs) were developed as the fluorescent probe for the efficient and sensitive detection of adenosine triphosphate (ATP) in a wide range of pH values. The fluorescence intensity of the Ag NCs could keep stable with pH values ranging from 2.5 to 9.3. The detection of ATP was based on the quenching of the fluorescent Ag NCs in the presence of ATP. The fluorescence quenching of the Ag NCs with increasing ATP concentration was studied at pH 2.5, 4.5, 7.0 and 8.5 which involved a wide pH environment in body fluids. The limit of detection (LOD) for ATP was as low as 0.1 mmol/L in an acidic environment with pH of 2.5 and all the linear correlation coefficients were satisfactory under wide-span pH values from 2.5 to 8.5. In addition, the sensitive determination of ATP was also achieved by adding copper ions (Cu2+). The high selectivity and rapid detection process proved that the fluorescent probe had great potential to detect ATP in biological samples under different pH conditions.
In this work, polymethacrylic acid (PMAA)-templated silver nanoclusters (Ag NCs) were developed as the fluorescent probe for the efficient and sensitive detection of adenosine triphosphate (ATP) in a wide range of pH values. The fluorescence intensity of the Ag NCs could keep stable with pH values ranging from 2.5 to 9.3. The detection of ATP was based on the quenching of the fluorescent Ag NCs in the presence of ATP. The fluorescence quenching of the Ag NCs with increasing ATP concentration was studied at pH 2.5, 4.5, 7.0 and 8.5 which involved a wide pH environment in body fluids. The limit of detection (LOD) for ATP was as low as 0.1 mmol/L in an acidic environment with pH of 2.5 and all the linear correlation coefficients were satisfactory under wide-span pH values from 2.5 to 8.5. In addition, the sensitive determination of ATP was also achieved by adding copper ions (Cu2+). The high selectivity and rapid detection process proved that the fluorescent probe had great potential to detect ATP in biological samples under different pH conditions.
2020, 31(12): 3121-3126
doi: 10.1016/j.cclet.2020.06.023
Abstract:
Combination therapy such as photothermal therapy (PTT) enhanced chemotherapy is regarded as a promising strategy for cancer treatment. Herein, we developed redox-responsive polymeric vesicles based on the amphiphilic triblock copolymer PCL-ss-PEG-ss-PCL. To avoid the limited therapeutic effect of chemotherapeutic drugs caused by systemic exposures and drug resistance, the redox-sensitive polymeric vesicles were cargoed with two chemotherapeutics: doxorubicin (DOX) and paclitaxel (PTX). Besides, indocyanine green (ICG) was encapsulated, and cell-penetrating peptides and LHRH targeting molecule were modified on the surface of polymeric vesicles. The results indicated that the polymeric vesicles can load different kinds of drugs with high drug loading content, trigger drug release in responsive to the reductive environment, realize high cellular uptake via dual peptides and laser irradiation, and achieve higher cytotoxicity via chemo-photothermal combination therapy. Hence, the redox-responsive LHRH/TAT dual peptides-conjugated PTX/DOX/ICG co-loaded polymeric micelles exhibited great potential in tumor-targeting and chemo-photothermal therapy.
Combination therapy such as photothermal therapy (PTT) enhanced chemotherapy is regarded as a promising strategy for cancer treatment. Herein, we developed redox-responsive polymeric vesicles based on the amphiphilic triblock copolymer PCL-ss-PEG-ss-PCL. To avoid the limited therapeutic effect of chemotherapeutic drugs caused by systemic exposures and drug resistance, the redox-sensitive polymeric vesicles were cargoed with two chemotherapeutics: doxorubicin (DOX) and paclitaxel (PTX). Besides, indocyanine green (ICG) was encapsulated, and cell-penetrating peptides and LHRH targeting molecule were modified on the surface of polymeric vesicles. The results indicated that the polymeric vesicles can load different kinds of drugs with high drug loading content, trigger drug release in responsive to the reductive environment, realize high cellular uptake via dual peptides and laser irradiation, and achieve higher cytotoxicity via chemo-photothermal combination therapy. Hence, the redox-responsive LHRH/TAT dual peptides-conjugated PTX/DOX/ICG co-loaded polymeric micelles exhibited great potential in tumor-targeting and chemo-photothermal therapy.
2020, 31(12): 3127-3130
doi: 10.1016/j.cclet.2020.06.031
Abstract:
Chemodynamic therapy (CDT) refers to generating hydroxyl radical (·OH) in tumor sites via hydrogen peroxide (H2O2) catalyzed by transition metal ions in cancer cells under acidic environment. However, H2O2 content is not enough for effective CDT, although H2O2 content in cancer cells is higher than that of normal cells. Herein, we synthesized DOX@BSA-Cu NPs (nanoparticles) for effective CDT by providing enhanced content of H2O2 in cancer cells. The results proved Cu2+ in NPs could be reduced to Cu+ by glutathione (GSH) and effectively converted H2O2 to ·OH. Moreover, the loaded low-dose doxorubicin (DOX) in the NPs could improve the content of H2O2 and resulted in more efficient generation of ·OH in cancer cells. Thus DOX@BSA-Cu NPs exhibited higher cytotoxicity to cancer cells. This research may provide new ideas for the further studies on more effective Cu(II)-based CDT nanoagents.
Chemodynamic therapy (CDT) refers to generating hydroxyl radical (·OH) in tumor sites via hydrogen peroxide (H2O2) catalyzed by transition metal ions in cancer cells under acidic environment. However, H2O2 content is not enough for effective CDT, although H2O2 content in cancer cells is higher than that of normal cells. Herein, we synthesized DOX@BSA-Cu NPs (nanoparticles) for effective CDT by providing enhanced content of H2O2 in cancer cells. The results proved Cu2+ in NPs could be reduced to Cu+ by glutathione (GSH) and effectively converted H2O2 to ·OH. Moreover, the loaded low-dose doxorubicin (DOX) in the NPs could improve the content of H2O2 and resulted in more efficient generation of ·OH in cancer cells. Thus DOX@BSA-Cu NPs exhibited higher cytotoxicity to cancer cells. This research may provide new ideas for the further studies on more effective Cu(II)-based CDT nanoagents.
2020, 31(12): 3131-3134
doi: 10.1016/j.cclet.2020.06.039
Abstract:
To explore the effects of microenvironmental adjustments on fluorescence, a pH-sensitive nano-composite system based on fluorescence resonance energy transfer (FRET) was constructed. The model system included a modified triblock copolymer (polyhistidine-b-polyethylene glycol-b-polycaprolactone) and gold nanoparticles. A near-infrared dye was used as the donor, and spectrally matched gold nanorods, attached after C-terminus modification with α-lipoic acid, were used as the receptor to realize control of the FRET effect over the fluorescence intensity for two polymer configurational changes (i.e., "folded" and "stretched" states) in response to pH. After synthesis and characterization, we investigated the self-assembly behavior of the system. Analysis by quartz crystal microbalance revealed the pH sensitivity of the polymer, which exhibited "folding" and "stretching" states with changes in pH, providing a structural basis for the FRET effect. Fluorescence spectrophotometry investigations also revealed the regulatory impact of the assembled system on fluorescence.
To explore the effects of microenvironmental adjustments on fluorescence, a pH-sensitive nano-composite system based on fluorescence resonance energy transfer (FRET) was constructed. The model system included a modified triblock copolymer (polyhistidine-b-polyethylene glycol-b-polycaprolactone) and gold nanoparticles. A near-infrared dye was used as the donor, and spectrally matched gold nanorods, attached after C-terminus modification with α-lipoic acid, were used as the receptor to realize control of the FRET effect over the fluorescence intensity for two polymer configurational changes (i.e., "folded" and "stretched" states) in response to pH. After synthesis and characterization, we investigated the self-assembly behavior of the system. Analysis by quartz crystal microbalance revealed the pH sensitivity of the polymer, which exhibited "folding" and "stretching" states with changes in pH, providing a structural basis for the FRET effect. Fluorescence spectrophotometry investigations also revealed the regulatory impact of the assembled system on fluorescence.
2020, 31(12): 3135-3138
doi: 10.1016/j.cclet.2020.07.010
Abstract:
Fragrances are widely used in many aspects of our lives. They cannot only make people happy, but also treat many diseases. However, excessively fast evaporation rate is one of the main obstacles to the use of spices. In this study, mesoporous silica nanorods (MSNRs) and hollow mesoporous silica nanorods (HMSNRs) were prepared to encapsulate eugenol. These two nano-fragrances were named eugenol@MSNRs and eugenol@HMSNRs, respectively. The morphologies, size, interior structures and pore performances of MSNRs and HMSNRs. Besides, the performances of encapsulation and fragrance release of eugenol@MSNRs and eugenol@HMSNRs were compared and analyzed. The results showed that eugenol@HMSNRs encapsulated more fragrance and were faster to encapsulate compared with eugenol@MSNRs. Both the release rates of eugenol from eugenol@MSNRs and eugenol@HMSNRs were slow. But the eugenol was released from eugenol@MSNRs more slowly.
Fragrances are widely used in many aspects of our lives. They cannot only make people happy, but also treat many diseases. However, excessively fast evaporation rate is one of the main obstacles to the use of spices. In this study, mesoporous silica nanorods (MSNRs) and hollow mesoporous silica nanorods (HMSNRs) were prepared to encapsulate eugenol. These two nano-fragrances were named eugenol@MSNRs and eugenol@HMSNRs, respectively. The morphologies, size, interior structures and pore performances of MSNRs and HMSNRs. Besides, the performances of encapsulation and fragrance release of eugenol@MSNRs and eugenol@HMSNRs were compared and analyzed. The results showed that eugenol@HMSNRs encapsulated more fragrance and were faster to encapsulate compared with eugenol@MSNRs. Both the release rates of eugenol from eugenol@MSNRs and eugenol@HMSNRs were slow. But the eugenol was released from eugenol@MSNRs more slowly.
2020, 31(12): 3139-3142
doi: 10.1016/j.cclet.2020.07.013
Abstract:
Silk has been widely used in the clothing industry due to their soft and smooth features, good biocompatibility, good heat dissipation, warmth and ultraviolet resistance. The application of fragrance to silk can significantly improve the performance of silk. However, there are two key scientific problems that need to be solved: slowing down the release rate of fragrances and increasing the scent lasting time of silk. In this study, cationic and temperature-sensitive liposomes were designed and prepared to encapsulate eugenol. These fragrance-loaded liposomes significantly slowed down the release rate of the fragrance and controlled the release rate of the fragrance in a thermo-sensitive manner. The liposomes adhered to the silk through electrostatic adsorption interaction. The positive charge on the fragrance-loaded liposomes neutralized much negative charge on silk and thereby increasing the adhesion efficiency.
Silk has been widely used in the clothing industry due to their soft and smooth features, good biocompatibility, good heat dissipation, warmth and ultraviolet resistance. The application of fragrance to silk can significantly improve the performance of silk. However, there are two key scientific problems that need to be solved: slowing down the release rate of fragrances and increasing the scent lasting time of silk. In this study, cationic and temperature-sensitive liposomes were designed and prepared to encapsulate eugenol. These fragrance-loaded liposomes significantly slowed down the release rate of the fragrance and controlled the release rate of the fragrance in a thermo-sensitive manner. The liposomes adhered to the silk through electrostatic adsorption interaction. The positive charge on the fragrance-loaded liposomes neutralized much negative charge on silk and thereby increasing the adhesion efficiency.
2020, 31(12): 3143-3148
doi: 10.1016/j.cclet.2020.07.027
Abstract:
Surface modification by poly(ethylene glycol) (PEGylation) has been acknowledged as a powerful strategy in minimizing non-specific reactions for biomedical devices. Once applied into manufacture of drug/gene delivery systems, PEGylation has demonstrated to significantly improve their biocompatibility and stealthiness in physiological environment. Nonetheless, reluctant cell membrane affinities thus cellular uptake efficiencies owing to PEGylation brought up further issues that are imperative to be resolved. Pertain to this PEGylation dilemma, we attempted to introduce peptide (GPLGVRG) linkage between block copolymer of PEG-poly{N'-[N-(2-aminoethyl)-2-aminoethyl]aspartamide} PAsp(DET), wherein the cationic PAsp(DET) could self-assemble with pDNA into nanoscaled complex core. Noteworthy was the peptide linkage whose amino acids sequence could be specifically recognized and degraded by matrix metalloproteinases (MMPs) (overexpressed in extracellular milieu of tumors). Therefore, our subsequent studies validated facile detachment of PEGylation from the aforementioned polyplex micelles upon treatment of MMPs, which elicited improved cytomembrane affinities and cellular uptake efficiencies. In addition, promoted escape from endosome entrapment was also confirmed through direct endosome membrane destabilization by PAsp(DET), which was further elucidated to be attributable to dePEGylation as well as elevated charged density of PAsp(DET) in acidic endosomes. These benefits from dePEGylation eventually contributed to promoted gene expression at the affected cells and potent tumor growth suppression based on anti-angiogenic approach. Therefore, our developed strategy has provided a facile approach in overcoming the dilemma of PEGylation, which could be informative in design of drug/gene delivery systems.
Surface modification by poly(ethylene glycol) (PEGylation) has been acknowledged as a powerful strategy in minimizing non-specific reactions for biomedical devices. Once applied into manufacture of drug/gene delivery systems, PEGylation has demonstrated to significantly improve their biocompatibility and stealthiness in physiological environment. Nonetheless, reluctant cell membrane affinities thus cellular uptake efficiencies owing to PEGylation brought up further issues that are imperative to be resolved. Pertain to this PEGylation dilemma, we attempted to introduce peptide (GPLGVRG) linkage between block copolymer of PEG-poly{N'-[N-(2-aminoethyl)-2-aminoethyl]aspartamide} PAsp(DET), wherein the cationic PAsp(DET) could self-assemble with pDNA into nanoscaled complex core. Noteworthy was the peptide linkage whose amino acids sequence could be specifically recognized and degraded by matrix metalloproteinases (MMPs) (overexpressed in extracellular milieu of tumors). Therefore, our subsequent studies validated facile detachment of PEGylation from the aforementioned polyplex micelles upon treatment of MMPs, which elicited improved cytomembrane affinities and cellular uptake efficiencies. In addition, promoted escape from endosome entrapment was also confirmed through direct endosome membrane destabilization by PAsp(DET), which was further elucidated to be attributable to dePEGylation as well as elevated charged density of PAsp(DET) in acidic endosomes. These benefits from dePEGylation eventually contributed to promoted gene expression at the affected cells and potent tumor growth suppression based on anti-angiogenic approach. Therefore, our developed strategy has provided a facile approach in overcoming the dilemma of PEGylation, which could be informative in design of drug/gene delivery systems.
2020, 31(12): 3149-3152
doi: 10.1016/j.cclet.2020.08.039
Abstract:
Considering that hydrogen peroxide (H2O2) plays significant roles in oxidative stress, the cellular signal transduction and essential biological process regulation, the detection and imaging of H2O2 in living systems undertakes critical responsibility. Herein, we have developed a novel two-photon fluorescence turn on probe, named as Pyp-B for mitochondria H2O2 detection in living systems. Selectivity studies show that probe Pyp-B exhibit highly sensitive response toward H2O2 than other reactive oxygen species (ROS) and reactive nitrogen species (RNS) as well as biologically relevant species. The fluorescence colocalization studies demonstrate that the probe can localize in the mitochondria solely. Furthermore, as a bio-compatibility molecule, the highly selective and sensitive of fluorescence probe Pyp-B have been confirmed by its cell imaging application of H2O2 in living A549 cells and zebrafishes under the physiological conditions.
Considering that hydrogen peroxide (H2O2) plays significant roles in oxidative stress, the cellular signal transduction and essential biological process regulation, the detection and imaging of H2O2 in living systems undertakes critical responsibility. Herein, we have developed a novel two-photon fluorescence turn on probe, named as Pyp-B for mitochondria H2O2 detection in living systems. Selectivity studies show that probe Pyp-B exhibit highly sensitive response toward H2O2 than other reactive oxygen species (ROS) and reactive nitrogen species (RNS) as well as biologically relevant species. The fluorescence colocalization studies demonstrate that the probe can localize in the mitochondria solely. Furthermore, as a bio-compatibility molecule, the highly selective and sensitive of fluorescence probe Pyp-B have been confirmed by its cell imaging application of H2O2 in living A549 cells and zebrafishes under the physiological conditions.
2020, 31(12): 3153-3157
doi: 10.1016/j.cclet.2020.03.077
Abstract:
Vascular endothelial growth factor (VEGF)-vascular endothelial growth factor receptor (VEGFR) pathways are essential in tumor angiogenesis, growth and metastasis. Studies on anti-angiogenic therapy have been mostly focused on the blockage of VEGF-VEGFR pathways. We report an extracellularly transformable peptide-based nanomaterial to develop artificial extracellular matrix (ECM)-like networks for high-efficient blockage of natural VEGF-VEGFR interactions. The transformable peptide-based nanomaterial transforms from nanoparticles into nanofibers upon binding to VEGFR in solution. In addition, the transformable peptide-based nanomaterial forms ECM-like fibrous networks on VEGFR overexpressed cells, inhibiting the VEGF-VEGFR interactions and the subsequent angiogenesis. The tube formation is reduced by nearly 85.1% after treatment. This strategy shows excellent potential for anti-angiogenesis, and inhibition of tumor invasion and metastasis.
Vascular endothelial growth factor (VEGF)-vascular endothelial growth factor receptor (VEGFR) pathways are essential in tumor angiogenesis, growth and metastasis. Studies on anti-angiogenic therapy have been mostly focused on the blockage of VEGF-VEGFR pathways. We report an extracellularly transformable peptide-based nanomaterial to develop artificial extracellular matrix (ECM)-like networks for high-efficient blockage of natural VEGF-VEGFR interactions. The transformable peptide-based nanomaterial transforms from nanoparticles into nanofibers upon binding to VEGFR in solution. In addition, the transformable peptide-based nanomaterial forms ECM-like fibrous networks on VEGFR overexpressed cells, inhibiting the VEGF-VEGFR interactions and the subsequent angiogenesis. The tube formation is reduced by nearly 85.1% after treatment. This strategy shows excellent potential for anti-angiogenesis, and inhibition of tumor invasion and metastasis.
2020, 31(12): 3158-3162
doi: 10.1016/j.cclet.2020.04.035
Abstract:
Chemo-photothermal treatment is one of the most efficient strategies for cancer therapy. However, traditional drug carriers without near-infrared absorption capacity need to be loaded with materials behaving photothermal properties, as it results in complicated synthesis process, inefficient photothermal effects and hindered NIR-mediated drug release. Herein we report a facile synthesis of a polyethylene glycol (PEG) linked liposome (PEG-liposomes) coated doxorubicin (DOX)-loaded ordered mesoporous carbon (OMC) nanocomponents (PEG-LIP@OMC/DOX) by simply sonicating DOX and OMC in PEG-liposomes suspensions. The as-obtained PEG-LIP@OMC/DOX exhibits a nanoscale size (600±15 nm), a negative surface potential (-36.70 mV), high drug loading (131.590 mg/g OMC), and excellent photothermal properties. The PEG-LIP@OMC/DOX can deliver loaded DOX to human MCF-7 breast cancer cells (MCF-7) and the cell toxicity viability shows that DOX unloaded PEG-LIP@OMC has no cytotoxicity, confirming the PEG-LIP@OMC itself has excellent biocompatibility. The NIR-triggered release studies demonstrate that this NIR-responsive drug delivery system enables on-demand drug release. Furthermore, cell viability results using human MCF-7 cells demonstrated that the combination of NIR-based hyperthermal therapy and triggered chemotherapy can provide higher therapeutic efficacy than respective monotherapies. With these excellent features, we believe that this phospholipid coating based multifunctional delivery system strategy should promote the application of OMC in nanomedical applications.
Chemo-photothermal treatment is one of the most efficient strategies for cancer therapy. However, traditional drug carriers without near-infrared absorption capacity need to be loaded with materials behaving photothermal properties, as it results in complicated synthesis process, inefficient photothermal effects and hindered NIR-mediated drug release. Herein we report a facile synthesis of a polyethylene glycol (PEG) linked liposome (PEG-liposomes) coated doxorubicin (DOX)-loaded ordered mesoporous carbon (OMC) nanocomponents (PEG-LIP@OMC/DOX) by simply sonicating DOX and OMC in PEG-liposomes suspensions. The as-obtained PEG-LIP@OMC/DOX exhibits a nanoscale size (600±15 nm), a negative surface potential (-36.70 mV), high drug loading (131.590 mg/g OMC), and excellent photothermal properties. The PEG-LIP@OMC/DOX can deliver loaded DOX to human MCF-7 breast cancer cells (MCF-7) and the cell toxicity viability shows that DOX unloaded PEG-LIP@OMC has no cytotoxicity, confirming the PEG-LIP@OMC itself has excellent biocompatibility. The NIR-triggered release studies demonstrate that this NIR-responsive drug delivery system enables on-demand drug release. Furthermore, cell viability results using human MCF-7 cells demonstrated that the combination of NIR-based hyperthermal therapy and triggered chemotherapy can provide higher therapeutic efficacy than respective monotherapies. With these excellent features, we believe that this phospholipid coating based multifunctional delivery system strategy should promote the application of OMC in nanomedical applications.
2020, 31(12): 3163-3167
doi: 10.1016/j.cclet.2020.04.038
Abstract:
The rapid identification of pathogens is crucial in controlling the food quality and safety. The proposed system for the rapid and label-free identification of pathogens is based on the principle of laser scattering from the bacterial microbes. The clinical prototype consists of three parts: the laser beam, photodetectors, and the data acquisition system. The bacterial testing sample was mixed with 10 mL distilled water and placed inside the machine chamber. When the bacterial microbes pass by the laser beam, the scattering of light occurs due to variation in size, shape, and morphology. Due to this reason, different types of pathogens show their unique light scattering patterns. The photo-detectors were arranged at the surroundings of the sample at different angles to collect the scattered light. The photodetectors convert the scattered light intensity into a voltage waveform. The waveform features were acquired by using the power spectral characteristics, and the dimensionality of extracted features was reduced by applying minimal-redundancy-maximal-relevance criterion (mRMR). A support vector machine (SVM) classifier was developed by training the selected power spectral features for the classification of three different bacterial microbes. The resulting average identification accuracies of E. faecalis, E. coli and S. aureus were 99%, 87%, and 94%, respectively. The overall experimental results yield a higher accuracy of 93.6%, indicating that the proposed device has the potential for label-free identification of pathogens with simplicity, rapidity, and cost-effectiveness.
The rapid identification of pathogens is crucial in controlling the food quality and safety. The proposed system for the rapid and label-free identification of pathogens is based on the principle of laser scattering from the bacterial microbes. The clinical prototype consists of three parts: the laser beam, photodetectors, and the data acquisition system. The bacterial testing sample was mixed with 10 mL distilled water and placed inside the machine chamber. When the bacterial microbes pass by the laser beam, the scattering of light occurs due to variation in size, shape, and morphology. Due to this reason, different types of pathogens show their unique light scattering patterns. The photo-detectors were arranged at the surroundings of the sample at different angles to collect the scattered light. The photodetectors convert the scattered light intensity into a voltage waveform. The waveform features were acquired by using the power spectral characteristics, and the dimensionality of extracted features was reduced by applying minimal-redundancy-maximal-relevance criterion (mRMR). A support vector machine (SVM) classifier was developed by training the selected power spectral features for the classification of three different bacterial microbes. The resulting average identification accuracies of E. faecalis, E. coli and S. aureus were 99%, 87%, and 94%, respectively. The overall experimental results yield a higher accuracy of 93.6%, indicating that the proposed device has the potential for label-free identification of pathogens with simplicity, rapidity, and cost-effectiveness.
2020, 31(12): 3168-3172
doi: 10.1016/j.cclet.2020.04.051
Abstract:
The copper(II) diethyldithiocarbamate (Cu(DDC)2) complex exhibited excellent inhibition to cancer cells. The usual administration is intravenous injection for disulfram and oral for copper. A new strategy was reported to improve the administration efficiency of the Cu(DDC)2 drug. Poly(lactide-co-glycolide) (PLGA) nanoparticles were used to trap disulfram and copper gluconate separately, the two types of drug loaded nanoparticles were injected in mesothelioma-bearing nude mice via intraperitoneal injection. The in vivo formation of Cu(DDC)2 complex was induced by disulfiram and Cu2+ released from PLGA nanoparticles. This strategy avoided many obstacles in the use of Cu(DDC)2 complex as chemotherapeutic and exhibited excellent anticancer activity to mesothelioma.
The copper(II) diethyldithiocarbamate (Cu(DDC)2) complex exhibited excellent inhibition to cancer cells. The usual administration is intravenous injection for disulfram and oral for copper. A new strategy was reported to improve the administration efficiency of the Cu(DDC)2 drug. Poly(lactide-co-glycolide) (PLGA) nanoparticles were used to trap disulfram and copper gluconate separately, the two types of drug loaded nanoparticles were injected in mesothelioma-bearing nude mice via intraperitoneal injection. The in vivo formation of Cu(DDC)2 complex was induced by disulfiram and Cu2+ released from PLGA nanoparticles. This strategy avoided many obstacles in the use of Cu(DDC)2 complex as chemotherapeutic and exhibited excellent anticancer activity to mesothelioma.
2020, 31(12): 3173-3177
doi: 10.1016/j.cclet.2020.05.020
Abstract:
Niobium carbide MXene quantum dots (Nb2C MQDs) derived from 2D Nb2CTx (MXene) are the rising-star material recently. Herein, a sulfur and nitrogen co-doped Nb2C MQDs (S, N-MQDs) were synthesized through a hydrothermal method. The obtained Nb2C MQDs have excellent green fluorescence with a quantum yield (QY) of 17.25%. In addition, they exhibited excitation-dependent photoluminescence, anti-photobleaching and dispersion stability. They emit light at 520 nm when excited at 390 nm. The Nb2C MQDs could be successfully applied to copper ion detection with detection limit of 2 μmol/L and Caco-2 cells imaging.
Niobium carbide MXene quantum dots (Nb2C MQDs) derived from 2D Nb2CTx (MXene) are the rising-star material recently. Herein, a sulfur and nitrogen co-doped Nb2C MQDs (S, N-MQDs) were synthesized through a hydrothermal method. The obtained Nb2C MQDs have excellent green fluorescence with a quantum yield (QY) of 17.25%. In addition, they exhibited excitation-dependent photoluminescence, anti-photobleaching and dispersion stability. They emit light at 520 nm when excited at 390 nm. The Nb2C MQDs could be successfully applied to copper ion detection with detection limit of 2 μmol/L and Caco-2 cells imaging.
2020, 31(12): 3178-3182
doi: 10.1016/j.cclet.2020.05.034
Abstract:
Hepatocellular carcinoma (HCC) has become the fourth predominant cause of cancer-related deaths worldwide, and HCC is still one of the worst prognoses for survival as it is poorly responsive to both chemotherapy and surgical treatment due to drug resistance and great toxic effects. Triptolide (TP), a key ingredient from the traditional Chinese medical herb, has been utilized to treat inflammation and antitumor for centuries. However, investigations of this potent agent have been met with only limited success due to the severe systemic toxicities in patients and low water solubility as well as its high toxicity over the past two decades. Herein, we reported the development of a reduction-responsive drug delivery system loaded with TP for glutathione (GSH)-triggered drug release for cancer therapy. With the GSH-sensitive TP loaded nanoparticles, the remarkable increases in tumor accumulation and amelioration of drug toxicity in animals are demonstrated, which is likely due to sustained stepwise release of active TP within cancer cells. Moreover, in a patient-derived tumor xenograft model of liver cancer, administration of tritolide nanoparticles enhances the antitumor efficacy relative to administration of free TP. These findings indicate that GSH-sensitive release of TP may be a promising strategy for cancer treatment.
Hepatocellular carcinoma (HCC) has become the fourth predominant cause of cancer-related deaths worldwide, and HCC is still one of the worst prognoses for survival as it is poorly responsive to both chemotherapy and surgical treatment due to drug resistance and great toxic effects. Triptolide (TP), a key ingredient from the traditional Chinese medical herb, has been utilized to treat inflammation and antitumor for centuries. However, investigations of this potent agent have been met with only limited success due to the severe systemic toxicities in patients and low water solubility as well as its high toxicity over the past two decades. Herein, we reported the development of a reduction-responsive drug delivery system loaded with TP for glutathione (GSH)-triggered drug release for cancer therapy. With the GSH-sensitive TP loaded nanoparticles, the remarkable increases in tumor accumulation and amelioration of drug toxicity in animals are demonstrated, which is likely due to sustained stepwise release of active TP within cancer cells. Moreover, in a patient-derived tumor xenograft model of liver cancer, administration of tritolide nanoparticles enhances the antitumor efficacy relative to administration of free TP. These findings indicate that GSH-sensitive release of TP may be a promising strategy for cancer treatment.
2020, 31(12): 3183-3189
doi: 10.1016/j.cclet.2020.05.035
Abstract:
Engineered nanomaterials have attracted significantly attention as one of the most promising antimicrobial agents for against multidrug resistant infections. The toxicological responses of nanomaterials are closely related to their physicochemical properties, and establishment of a structure-activity relationship for nanomaterials at the nano-bio interface is of great significance for deep understanding antibacterial toxicity mechanisms of nanomaterials and designing safer antibacterial nanomaterials. In this study, the antibacterial behaviors of well-defined crystallographic facets of a series of Au nanocrystals, including {100}-facet cubes, {110}-facet rhombic dodecahedra, {111}-facet octahedra, {221}-facet trisoctahedra and {720}-facet concave cubes, was investigated, using the model bacteria Staphylococcus aureus. We find that Au nanocrystals display substantial facet-dependent antibacterial activities. The low-index facets of cubes, octahedra, and rhombic dodecahedra show considerable antibacterial activity, whereas the high-index facets of trisoctahedra and concave cubes remained inert under biological conditions. This result is in stark contrast to the previous paradigm that the high-index facets were considered to have higher bioactivity as compared with low-index facets. The antibacterial mechanism studies have shown that the facet-dependent antibacterial behaviors of Au nanocrystals are mainly caused by differential bacterial membrane damage as well as inhibition of cellular enzymatic activity and energy metabolism. The faceted Au nanocrystals are unique in that they do not induce generation of reactive oxygen species, as validated for most antibiotics and antimicrobial nanostructures. Our findings may provide a deeper understanding of facet-dependent toxicological responses and suggest the complexities of the nanomaterial-cell interactions, shedding some light on the development of high performance Au nanomaterials-based antibacterial therapeutics.
Engineered nanomaterials have attracted significantly attention as one of the most promising antimicrobial agents for against multidrug resistant infections. The toxicological responses of nanomaterials are closely related to their physicochemical properties, and establishment of a structure-activity relationship for nanomaterials at the nano-bio interface is of great significance for deep understanding antibacterial toxicity mechanisms of nanomaterials and designing safer antibacterial nanomaterials. In this study, the antibacterial behaviors of well-defined crystallographic facets of a series of Au nanocrystals, including {100}-facet cubes, {110}-facet rhombic dodecahedra, {111}-facet octahedra, {221}-facet trisoctahedra and {720}-facet concave cubes, was investigated, using the model bacteria Staphylococcus aureus. We find that Au nanocrystals display substantial facet-dependent antibacterial activities. The low-index facets of cubes, octahedra, and rhombic dodecahedra show considerable antibacterial activity, whereas the high-index facets of trisoctahedra and concave cubes remained inert under biological conditions. This result is in stark contrast to the previous paradigm that the high-index facets were considered to have higher bioactivity as compared with low-index facets. The antibacterial mechanism studies have shown that the facet-dependent antibacterial behaviors of Au nanocrystals are mainly caused by differential bacterial membrane damage as well as inhibition of cellular enzymatic activity and energy metabolism. The faceted Au nanocrystals are unique in that they do not induce generation of reactive oxygen species, as validated for most antibiotics and antimicrobial nanostructures. Our findings may provide a deeper understanding of facet-dependent toxicological responses and suggest the complexities of the nanomaterial-cell interactions, shedding some light on the development of high performance Au nanomaterials-based antibacterial therapeutics.
2020, 31(12): 3190-3194
doi: 10.1016/j.cclet.2020.07.002
Abstract:
Biomimetic scaffolds present the promising potential for bone regeneration. As a natural gel-like traditional food, tofu with porous architecture and proved biological safety indicated a good potential to be a natural scaffold and easy to be improved by surface modification. Hereon, we fabricated the tofubased scaffolds and systematically explored the potential for bone tissue engineering. In addition, the collagen has been introduced by simple coating to further enhance the surface compatibility of the tofubased scaffold in bone regeneration. The results showed that the tofu-based scaffolds possessed good porous structure and cytocompatibility. Notably, the tofu-based scaffolds could improve the expression of osteogenesis-related genes and proteins, leading to better bone regeneration after 2 months of implantation. All the results indicated that tofu would become an outstanding sustainable natural porous scaffold for bone regeneration with excellent bioactivities.
Biomimetic scaffolds present the promising potential for bone regeneration. As a natural gel-like traditional food, tofu with porous architecture and proved biological safety indicated a good potential to be a natural scaffold and easy to be improved by surface modification. Hereon, we fabricated the tofubased scaffolds and systematically explored the potential for bone tissue engineering. In addition, the collagen has been introduced by simple coating to further enhance the surface compatibility of the tofubased scaffold in bone regeneration. The results showed that the tofu-based scaffolds possessed good porous structure and cytocompatibility. Notably, the tofu-based scaffolds could improve the expression of osteogenesis-related genes and proteins, leading to better bone regeneration after 2 months of implantation. All the results indicated that tofu would become an outstanding sustainable natural porous scaffold for bone regeneration with excellent bioactivities.
2020, 31(12): 3195-3199
doi: 10.1016/j.cclet.2020.07.011
Abstract:
Peptide self-assembled nanomaterials have attracted more and more attention due to their wide applications such as drug delivery, cell imaging, and real-time drug monitoring. However, the application of the peptide is still limited by its inherent optical properties. Here we proposed and prepared a series of fluorescent tripeptide nanoparticles (TPNPs) through π-π stacking and zinc coordination. The experimental results show that the nanoparticles (TPNPs1) formed by the self-assembly of the tripeptide tryptophan-tryptophan-tryptophan have the highest fluorescence intensity, uniform and appropriate size, and low cytotoxicity. Furthermore, there was fluorescence resonance between TPNPs1 and doxorubicin, which has been successfully applied for real-time cell imaging and drug release monitoring.
Peptide self-assembled nanomaterials have attracted more and more attention due to their wide applications such as drug delivery, cell imaging, and real-time drug monitoring. However, the application of the peptide is still limited by its inherent optical properties. Here we proposed and prepared a series of fluorescent tripeptide nanoparticles (TPNPs) through π-π stacking and zinc coordination. The experimental results show that the nanoparticles (TPNPs1) formed by the self-assembly of the tripeptide tryptophan-tryptophan-tryptophan have the highest fluorescence intensity, uniform and appropriate size, and low cytotoxicity. Furthermore, there was fluorescence resonance between TPNPs1 and doxorubicin, which has been successfully applied for real-time cell imaging and drug release monitoring.
2020, 31(12): 3200-3204
doi: 10.1016/j.cclet.2020.05.036
Abstract:
Li2FeTiO4 composites have been produced using commercial LiAC, FeCl2 and different titanium sources by hydrothermal synthesis (HS) at 175 ℃ and subsequent annealing at 700 ℃. Impure phase TiO2, Fe2O3 and FeTiO4 were detected out among the Li2FeTiO4 composites with different titanium sources. Micron and nano-sized particles of Li2FeTiO4 were prepared from various titanium raw materials, with nano-sized particles predominating when titanium raw materials were layered hydrogen titanate nanowire (H2Ti3O7NW, HTO-NW) and titanium oxide nanotubes (TiO2NB). The Li2FeTiO4 composites synthesized by HTO-NW shows a primary particle size of 50-200 nm of high crystallinity staggered with undissolved nanowire with a diameter size of about 100 nm. The samples using one-dimensional nanometer titanium oxide (TiO2 NB) as the raw material can get a super high initial discharge capacity of 367.8 mAh/g at the rate of C/10 and excellent cycling stability. The selection of raw materials and adopting multi-phase modification can be considered as an effective strategy to improve the electro-chemical properties of Li2FeTiO4 composite cathode materials for the lithium secondary battery.
Li2FeTiO4 composites have been produced using commercial LiAC, FeCl2 and different titanium sources by hydrothermal synthesis (HS) at 175 ℃ and subsequent annealing at 700 ℃. Impure phase TiO2, Fe2O3 and FeTiO4 were detected out among the Li2FeTiO4 composites with different titanium sources. Micron and nano-sized particles of Li2FeTiO4 were prepared from various titanium raw materials, with nano-sized particles predominating when titanium raw materials were layered hydrogen titanate nanowire (H2Ti3O7NW, HTO-NW) and titanium oxide nanotubes (TiO2NB). The Li2FeTiO4 composites synthesized by HTO-NW shows a primary particle size of 50-200 nm of high crystallinity staggered with undissolved nanowire with a diameter size of about 100 nm. The samples using one-dimensional nanometer titanium oxide (TiO2 NB) as the raw material can get a super high initial discharge capacity of 367.8 mAh/g at the rate of C/10 and excellent cycling stability. The selection of raw materials and adopting multi-phase modification can be considered as an effective strategy to improve the electro-chemical properties of Li2FeTiO4 composite cathode materials for the lithium secondary battery.
2020, 31(12): 3205-3208
doi: 10.1016/j.cclet.2020.07.031
Abstract:
Selenization of Fe2O3 with NaHSe led to Se/Fe3O4. The unexpected generation of Fe3O4 attributed to the reduction conditions of the reaction, and the resulted magnetic features of the material facilitated its separation in practical applications. Owning to the synergistic effect of Se with Fe, the material was especially active to catalyze the oxidative C=C scission using O2 as mild oxidant. The technique has been successfully applied in polyene degradation project, which is of profound practical values for the treatment of the polyene pigment pollution and may be applied in the food and pharmaceutical industry.
Selenization of Fe2O3 with NaHSe led to Se/Fe3O4. The unexpected generation of Fe3O4 attributed to the reduction conditions of the reaction, and the resulted magnetic features of the material facilitated its separation in practical applications. Owning to the synergistic effect of Se with Fe, the material was especially active to catalyze the oxidative C=C scission using O2 as mild oxidant. The technique has been successfully applied in polyene degradation project, which is of profound practical values for the treatment of the polyene pigment pollution and may be applied in the food and pharmaceutical industry.
2020, 31(12): 3209-3212
doi: 10.1016/j.cclet.2020.05.006
Abstract:
Constructing a reliable and favorable electrode-electrolyte interface is crucial to utilize the exceptional energy storage capability in commercial lithium-ion batteries. Here, we report a facile synthesis approach for the lithium difluorophosphate (LiPO2F2) solution as an effective film-forming additive via direct adding the Li2CO3 into LiPF6 solution at 45 ℃. Benefiting from the significantly reduced interface resistance (RSEI) and charge transfer impedance (Rct) of both the cathode and anode by adding the prepared LiPO2F2 solution into a baseline electrolyte, the cycling performance of the graphite‖LiNi0.5Mn0.3Co0.2O2 pouch cell is remarkably improved under all-climate condition.
Constructing a reliable and favorable electrode-electrolyte interface is crucial to utilize the exceptional energy storage capability in commercial lithium-ion batteries. Here, we report a facile synthesis approach for the lithium difluorophosphate (LiPO2F2) solution as an effective film-forming additive via direct adding the Li2CO3 into LiPF6 solution at 45 ℃. Benefiting from the significantly reduced interface resistance (RSEI) and charge transfer impedance (Rct) of both the cathode and anode by adding the prepared LiPO2F2 solution into a baseline electrolyte, the cycling performance of the graphite‖LiNi0.5Mn0.3Co0.2O2 pouch cell is remarkably improved under all-climate condition.
2020, 31(12): 3213-3215
doi: 10.1016/j.cclet.2020.08.025
Abstract:
A new copper-thiolate cluster assembled framework [Cu2(μ4-SCH3)Cl]n (1), has been solvothermally synthesized through in situ reaction viz., in situ ligand generation and metal reduction. Compound 1 represents the first 3D framework based on Atlas-sphere functionalized by single μ2-Cl- groups. DOS calculation reveals the interaction of electronic structures. It is found that the HOMO is mainly distributed on Cl, Cu and S bonding orbitals, while the LUMO is dominated by Cu-Cl antibonding orbitals.
A new copper-thiolate cluster assembled framework [Cu2(μ4-SCH3)Cl]n (1), has been solvothermally synthesized through in situ reaction viz., in situ ligand generation and metal reduction. Compound 1 represents the first 3D framework based on Atlas-sphere functionalized by single μ2-Cl- groups. DOS calculation reveals the interaction of electronic structures. It is found that the HOMO is mainly distributed on Cl, Cu and S bonding orbitals, while the LUMO is dominated by Cu-Cl antibonding orbitals.
2020, 31(12): 3216-3220
doi: 10.1016/j.cclet.2020.03.067
Abstract:
For drop-on-demand (DOD) inkjet printing, stable and single ink droplet formation without satellite dots is the key to improve the print quality. The formation of stable and single droplet is influenced by filament break up and the polymer chain's coil-stretch transition behavior. In this paper, the droplet formation behaviors of polyfluorene (PFO) ink at various driving voltages (V), polymer chain's coil-stretch transition mechanism and its effects on single ink droplet formation are investigated. It indicates that when 58 < V ≤ 63 V, a single and stable droplet is formed with a pulse time of 38.5 μs. At this stage, the Weissenberg number (Wi) < 0.5, the PFO molecular chain is coiled to guarantee stable and single droplets. When V > 63 V, Wi > 0.5, the PFO molecular chain is stretched because of the high hydrodynamic forces, resulting unwanted satellite droplets. When 55 < V ≤ 58 V, the droplet shrinks into the nozzle, which indicates that the kinetic energy supplied by the deformation of the piezoelectric transducer isn't enough to force the droplet to be jetted from the nozzle.
For drop-on-demand (DOD) inkjet printing, stable and single ink droplet formation without satellite dots is the key to improve the print quality. The formation of stable and single droplet is influenced by filament break up and the polymer chain's coil-stretch transition behavior. In this paper, the droplet formation behaviors of polyfluorene (PFO) ink at various driving voltages (V), polymer chain's coil-stretch transition mechanism and its effects on single ink droplet formation are investigated. It indicates that when 58 < V ≤ 63 V, a single and stable droplet is formed with a pulse time of 38.5 μs. At this stage, the Weissenberg number (Wi) < 0.5, the PFO molecular chain is coiled to guarantee stable and single droplets. When V > 63 V, Wi > 0.5, the PFO molecular chain is stretched because of the high hydrodynamic forces, resulting unwanted satellite droplets. When 55 < V ≤ 58 V, the droplet shrinks into the nozzle, which indicates that the kinetic energy supplied by the deformation of the piezoelectric transducer isn't enough to force the droplet to be jetted from the nozzle.
2020, 31(12): 3221-3224
doi: 10.1016/j.cclet.2020.03.074
Abstract:
A hybrid system containing a pillar[5]arene unit and ten crown ether moieties was developed. The LCST behavior and thermo-responsiveness were successfully introduced into this pillar[5]arene-crown ether system. Both host-guest interactions and salting-out effect displayed great effects in realizing the supramolecular control over LCST properties and thermo-responsiveness. Compared with the individual macrocycles, this hybrid macrocycle system dramatically amplified the supramolecular control effect over LCST behavior.
A hybrid system containing a pillar[5]arene unit and ten crown ether moieties was developed. The LCST behavior and thermo-responsiveness were successfully introduced into this pillar[5]arene-crown ether system. Both host-guest interactions and salting-out effect displayed great effects in realizing the supramolecular control over LCST properties and thermo-responsiveness. Compared with the individual macrocycles, this hybrid macrocycle system dramatically amplified the supramolecular control effect over LCST behavior.
2020, 31(12): 3225-3229
doi: 10.1016/j.cclet.2020.04.020
Abstract:
The development of heterogeneous catalysts with substrate shape, size or electronic constitution selectivity is a huge challenge in photocatalysis. Reported herein is a host-guest interaction strategy to endow photocatalysts with special selectivity. By adjusting the precursors, conjugated macrocycle polymers (CMPs) with pillar[5]arene struts (CMP-1 and CMP-2) and a corresponding non-pillar[5]arene-contained conjugated organic polymer (COP-1) were prepared and the photocatalytic activities toward sulfide derivatives were investigated. The sulfides showed similar conversions when COP-1 was used as a photocatalyst, but exhibited significant differences when it turned to the CMPs. Remarkably, the conversion yield of S-1 achieved near 18 folds over the one of S-2 when CMP-2 was used as a catalyst. Mechanism studies confirmed that the "host-guest" effect of pillar[5]arene struts in CMPs was the main cause of the difference. The present work establishes CMPs as novel heterogeneous photocatalysts with substrate selectivity, and such a method will inspire the researchers concerning preparation of heterogeneous catalysts with excellent selectivity.
The development of heterogeneous catalysts with substrate shape, size or electronic constitution selectivity is a huge challenge in photocatalysis. Reported herein is a host-guest interaction strategy to endow photocatalysts with special selectivity. By adjusting the precursors, conjugated macrocycle polymers (CMPs) with pillar[5]arene struts (CMP-1 and CMP-2) and a corresponding non-pillar[5]arene-contained conjugated organic polymer (COP-1) were prepared and the photocatalytic activities toward sulfide derivatives were investigated. The sulfides showed similar conversions when COP-1 was used as a photocatalyst, but exhibited significant differences when it turned to the CMPs. Remarkably, the conversion yield of S-1 achieved near 18 folds over the one of S-2 when CMP-2 was used as a catalyst. Mechanism studies confirmed that the "host-guest" effect of pillar[5]arene struts in CMPs was the main cause of the difference. The present work establishes CMPs as novel heterogeneous photocatalysts with substrate selectivity, and such a method will inspire the researchers concerning preparation of heterogeneous catalysts with excellent selectivity.
2020, 31(12): 3230-3232
doi: 10.1016/j.cclet.2020.02.037
Abstract:
The binding behavior of pillar[5]arenes (P5As) towards a series of olefin guests ((E)-1, 4-dichlorobut-2-ene (1E), (Z)-1, 4-dichlorobut-2-ene (1Z), (E)-but-2-ene-1, 4-diol (2E), and (Z)-but-2-ene-1, 4-diol (2Z), as well as an alkyne derivative 1, 4-dichlorobut-2-yne (3)) have been studied in organic solution. P5As exhibit considerable selectivities for the trans-olefin isomers (1E and 2E) over their cis-isomers (1Z and 2Z). The cis/trans-selective interactions hold the potential of utilizing P5As to separate olefin isomers.
The binding behavior of pillar[5]arenes (P5As) towards a series of olefin guests ((E)-1, 4-dichlorobut-2-ene (1E), (Z)-1, 4-dichlorobut-2-ene (1Z), (E)-but-2-ene-1, 4-diol (2E), and (Z)-but-2-ene-1, 4-diol (2Z), as well as an alkyne derivative 1, 4-dichlorobut-2-yne (3)) have been studied in organic solution. P5As exhibit considerable selectivities for the trans-olefin isomers (1E and 2E) over their cis-isomers (1Z and 2Z). The cis/trans-selective interactions hold the potential of utilizing P5As to separate olefin isomers.
2020, 31(12): 3233-3236
doi: 10.1016/j.cclet.2020.07.018
Abstract:
A versatile heteropoly acid (H3PMo12O40)-catalyzed coupling of diarylmethanols with epoxides was established for the synthesis of polyaryl-substituted aldehydes. Furthermore, the catalytic system was also suitable for the reaction of diarylmethanols and diols/aldehydes. The application of such an earthabundant, readily accessible, and nontoxic catalyst provides a green approach for the construction of polyaryl-substituted aldehydes.
A versatile heteropoly acid (H3PMo12O40)-catalyzed coupling of diarylmethanols with epoxides was established for the synthesis of polyaryl-substituted aldehydes. Furthermore, the catalytic system was also suitable for the reaction of diarylmethanols and diols/aldehydes. The application of such an earthabundant, readily accessible, and nontoxic catalyst provides a green approach for the construction of polyaryl-substituted aldehydes.
2020, 31(12): 3237-3240
doi: 10.1016/j.cclet.2020.08.046
Abstract:
Cp*Co(Ⅲ)-catalyzed direct C-H amidation of azines has been developed. This conversion could proceed smoothly in the absence of external oxidants, acids or bases, with excellent regioselectivity and broad functional group tolerance. CO2 was released as the sole byproduct, thus providing an environmentally benign amidation process. The products obtained are important intermediates in organic synthesis.
Cp*Co(Ⅲ)-catalyzed direct C-H amidation of azines has been developed. This conversion could proceed smoothly in the absence of external oxidants, acids or bases, with excellent regioselectivity and broad functional group tolerance. CO2 was released as the sole byproduct, thus providing an environmentally benign amidation process. The products obtained are important intermediates in organic synthesis.
2020, 31(12): 3241-3244
doi: 10.1016/j.cclet.2020.07.017
Abstract:
An energy-saving and eco-friendly method for the efficient construction of various tri- and tetra-substituted pyrrolecarbonitriles through ultrasound-assisted multicomponent tandem reaction of readily available alkenes, TMSCN and N, N-disubstituted formamides within 40 min under metal-, solvent-free and mild conditions was developed. The dual role of iodine (catalyst and oxidant) notably simplified the reaction conditions and reduced the chemical waste generated.
An energy-saving and eco-friendly method for the efficient construction of various tri- and tetra-substituted pyrrolecarbonitriles through ultrasound-assisted multicomponent tandem reaction of readily available alkenes, TMSCN and N, N-disubstituted formamides within 40 min under metal-, solvent-free and mild conditions was developed. The dual role of iodine (catalyst and oxidant) notably simplified the reaction conditions and reduced the chemical waste generated.
Visible light-induced hydroxyalkylation of 2H-benzothiazoles with alcohols via selectfluor oxidation
2020, 31(12): 3245-3249
doi: 10.1016/j.cclet.2020.05.022
Abstract:
A visible-light induced metal-free approach was described for the hydroxyalkylation of 2H-benzothiazoles with alcohols by using selectfluor as the oxidant. A variety of 2H-benzothiazoles and alcohols could be tolerated, providing a mild and simple method for the synthesis of C2-hydroxyalkylated 2H-benzothiazoles in moderate to good yields. Besides, ethers were also compatible in this reaction, leading to corresponding C2 ether-substituted 2H-benzothiazoles with high regioselectivity.
A visible-light induced metal-free approach was described for the hydroxyalkylation of 2H-benzothiazoles with alcohols by using selectfluor as the oxidant. A variety of 2H-benzothiazoles and alcohols could be tolerated, providing a mild and simple method for the synthesis of C2-hydroxyalkylated 2H-benzothiazoles in moderate to good yields. Besides, ethers were also compatible in this reaction, leading to corresponding C2 ether-substituted 2H-benzothiazoles with high regioselectivity.
2020, 31(12): 3250-3254
doi: 10.1016/j.cclet.2020.04.008
Abstract:
As balanced electron-rich P, C-chelating ligands, phosphine-phosphonium-ylides are considered for their ability to in situ promote palladium-catalysed direct C(sp2)-H arylation. Using methyl phosphonium salts of 2, 2'-bis(diphenylphosphino)-1, 1'-binaphtyl ("methyl-BINAPIUM") as ylide precursors under optimized reaction conditions, arylation of benzoxazole was found to proceed in moderate to high yield to give functional 2-aryl benzoxazoles. A strong anion effect of the non-salt free ylide was evidenced (TfO- > I- > PF6- ≈ salt-free). This first example of phosphonium ylides as ligands in catalytic C-H activation extends the prospect of their general implementation in homogeneous transition metal catalysis.
As balanced electron-rich P, C-chelating ligands, phosphine-phosphonium-ylides are considered for their ability to in situ promote palladium-catalysed direct C(sp2)-H arylation. Using methyl phosphonium salts of 2, 2'-bis(diphenylphosphino)-1, 1'-binaphtyl ("methyl-BINAPIUM") as ylide precursors under optimized reaction conditions, arylation of benzoxazole was found to proceed in moderate to high yield to give functional 2-aryl benzoxazoles. A strong anion effect of the non-salt free ylide was evidenced (TfO- > I- > PF6- ≈ salt-free). This first example of phosphonium ylides as ligands in catalytic C-H activation extends the prospect of their general implementation in homogeneous transition metal catalysis.
2020, 31(12): 3255-3258
doi: 10.1016/j.cclet.2020.03.007
Abstract:
An efficient method for the synthesis of functionalized chroman-4-ones induced by visible light via the radical cyclization reaction of sulfinic acids and o-(allyloxy)arylaldehydes at room temperature was described. The corresponding products were isolated with moderate to good yields. Radical mechanism was proposed for this transformation. Anti-microbial activity of some desired compounds were screened.
An efficient method for the synthesis of functionalized chroman-4-ones induced by visible light via the radical cyclization reaction of sulfinic acids and o-(allyloxy)arylaldehydes at room temperature was described. The corresponding products were isolated with moderate to good yields. Radical mechanism was proposed for this transformation. Anti-microbial activity of some desired compounds were screened.
2020, 31(12): 3259-3262
doi: 10.1016/j.cclet.2020.02.057
Abstract:
A novel upper-rim functionalized calix[4]squaramide organocatalyst bearing bis-squaramide and cyclohexanediamine scaffolds was designed and prepared to catalyse a serial of asymmetric Michael addition of 1, 3-dicarbonyl compounds to α, β-unsaturated carbonyl compounds in high yields (up to 99 %) and good to excellent enantiomeric excesses (up to 99% ee). The comparative experiments indicated that the cooperative effect between calixarenes cavitives and chiral catalytic centers on this calix[4]squaramide catalyst could promote these reactions. Moreover, this strategy also provides valuable and easy access to chiral chromene, naphthoquinone and acetylacetone derivatives, which are important skeletons in biological and pharmaceutical compounds.
A novel upper-rim functionalized calix[4]squaramide organocatalyst bearing bis-squaramide and cyclohexanediamine scaffolds was designed and prepared to catalyse a serial of asymmetric Michael addition of 1, 3-dicarbonyl compounds to α, β-unsaturated carbonyl compounds in high yields (up to 99 %) and good to excellent enantiomeric excesses (up to 99% ee). The comparative experiments indicated that the cooperative effect between calixarenes cavitives and chiral catalytic centers on this calix[4]squaramide catalyst could promote these reactions. Moreover, this strategy also provides valuable and easy access to chiral chromene, naphthoquinone and acetylacetone derivatives, which are important skeletons in biological and pharmaceutical compounds.
2020, 31(12): 3263-3266
doi: 10.1016/j.cclet.2020.03.080
Abstract:
Pd-catalyzed oxidative homocoupling of 2-arylquinazolinones was successfully developed for the direct construction of biaryls via C-H bond activation. New well-defined structure that possessed two quinazolinone units was obtained with high efficiency and atomic economy. The protocols offer an efficient approach to the synthetically useful and functionalized biaryls in good yields using quinazolinone as a directing group.
Pd-catalyzed oxidative homocoupling of 2-arylquinazolinones was successfully developed for the direct construction of biaryls via C-H bond activation. New well-defined structure that possessed two quinazolinone units was obtained with high efficiency and atomic economy. The protocols offer an efficient approach to the synthetically useful and functionalized biaryls in good yields using quinazolinone as a directing group.
2020, 31(12): 3267-3270
doi: 10.1016/j.cclet.2020.04.042
Abstract:
An efficient procedure for the selective preparation of hydroxy-, carbonyl- and acetal-containing 2-pyrrolidinones has been developed through radical cyclization of 1, 6-dienes initiated by α-C(sp3)-H functionalization of alcohols. This protocol could be conducted at catalyst-free conditions at relatively low temperature (80 ℃) by employing commercially available tert-butyl peroxybenzoate (TBPB) as the oxidant.
An efficient procedure for the selective preparation of hydroxy-, carbonyl- and acetal-containing 2-pyrrolidinones has been developed through radical cyclization of 1, 6-dienes initiated by α-C(sp3)-H functionalization of alcohols. This protocol could be conducted at catalyst-free conditions at relatively low temperature (80 ℃) by employing commercially available tert-butyl peroxybenzoate (TBPB) as the oxidant.
2020, 31(12): 3271-3275
doi: 10.1016/j.cclet.2020.05.007
Abstract:
As a potential photochromic system, acylhydrazones exhibit many outstanding advantages including low cost, simple synthesis and high modifiability compared with some classic photochromic systems. However, the absorption wavelengths of acylhydrazones usually locate in ultraviolet region, which makes the band separation between the absorbance maxima of its irradiated and unirradiated forms cannot be observed by naked eyes and greatly limits their practical applications. In this work, a simple strategy for constructing acylhydrazone photochromic system with visible color/emission change is provided. Rhodamine 6G hydrazine-2-aldehyde-pyridine Schiff base (compound 3) is designed and synthesized by combining acylhydrazone with Rhodamine 6G structure. The introduction of Rhodamine 6G moiety to 3 not only makes it remain all the advantages of acylhydrazone photochromic system but also exhibits visible photo-induced color/emission changes both in solution and in a solid matrix. Moreover, 3 exhibits reversible photochromic property with good fatigue resistance, which makes it an excellent candidate for photo-patterning.
As a potential photochromic system, acylhydrazones exhibit many outstanding advantages including low cost, simple synthesis and high modifiability compared with some classic photochromic systems. However, the absorption wavelengths of acylhydrazones usually locate in ultraviolet region, which makes the band separation between the absorbance maxima of its irradiated and unirradiated forms cannot be observed by naked eyes and greatly limits their practical applications. In this work, a simple strategy for constructing acylhydrazone photochromic system with visible color/emission change is provided. Rhodamine 6G hydrazine-2-aldehyde-pyridine Schiff base (compound 3) is designed and synthesized by combining acylhydrazone with Rhodamine 6G structure. The introduction of Rhodamine 6G moiety to 3 not only makes it remain all the advantages of acylhydrazone photochromic system but also exhibits visible photo-induced color/emission changes both in solution and in a solid matrix. Moreover, 3 exhibits reversible photochromic property with good fatigue resistance, which makes it an excellent candidate for photo-patterning.
2020, 31(12): 3276-3278
doi: 10.1016/j.cclet.2020.06.033
Abstract:
Selenized glucose can be easily prepared via the selenization reaction of glucose using in situ generated NaHSe as the selenization reagent. The technique has been industrialized to produce the chemical in kilogram scale, making it an easily available material in laboratory presently. The selenized glucose may be widely used as the starting material for the preparation of selenium-containing catalysts, as the organoselenium additive for feeds, and as the efficient selenium-enriched foliar fertilizers. In this work, we found that treating Fusarium graminearum, a fungal pathogen inciting wheat scab disease, with selenium glucose could significantly inhibit the generation of the deoxynivalenol (DON) toxin, which might be a breakthrough for reducing the detriment of the wheat scab disease.
Selenized glucose can be easily prepared via the selenization reaction of glucose using in situ generated NaHSe as the selenization reagent. The technique has been industrialized to produce the chemical in kilogram scale, making it an easily available material in laboratory presently. The selenized glucose may be widely used as the starting material for the preparation of selenium-containing catalysts, as the organoselenium additive for feeds, and as the efficient selenium-enriched foliar fertilizers. In this work, we found that treating Fusarium graminearum, a fungal pathogen inciting wheat scab disease, with selenium glucose could significantly inhibit the generation of the deoxynivalenol (DON) toxin, which might be a breakthrough for reducing the detriment of the wheat scab disease.
