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2021 Volume 32 Issue 5
2021, 32(5): 1589-1590
doi: 10.1016/j.cclet.2021.03.013
Abstract:
2021, 32(5): 1591-1592
doi: 10.1016/j.cclet.2021.02.067
Abstract:
The recent electrocatalytic three-component annulation-halosulfonylation of 1, 6-enynes toward 1-indanones is highlighted.
The recent electrocatalytic three-component annulation-halosulfonylation of 1, 6-enynes toward 1-indanones is highlighted.
2021, 32(5): 1593-1602
doi: 10.1016/j.cclet.2020.12.054
Abstract:
Due to their high specificity and affinity towards various targets, along with other unique advantages such as stability and low cost, aptamers are widely applied in analytical techniques. A typical aptamer-based electrochemical biosensor is composed of a aptamer as the biological recognition element and transducer converting the biologic interaction into electrical signals for the quantitative measurement of targets. Improvement of the sensitivity of a biosensor is significantly important in order to achieve the detection of biomolecules with low abundance, and different amplification strategies have been explored. The strategies either employ nanomaterials such as gold nanoparticles to construct electrodes which can transfer the biological reactions more efficiently, or attempt to obtain enhanced signal through multi-labeled carriers or utilize enzyme mimics to catalyze redox cycling. This review discusses recent advances in signal amplification methods and their applications. Critical assessment of each method is also considered.
Due to their high specificity and affinity towards various targets, along with other unique advantages such as stability and low cost, aptamers are widely applied in analytical techniques. A typical aptamer-based electrochemical biosensor is composed of a aptamer as the biological recognition element and transducer converting the biologic interaction into electrical signals for the quantitative measurement of targets. Improvement of the sensitivity of a biosensor is significantly important in order to achieve the detection of biomolecules with low abundance, and different amplification strategies have been explored. The strategies either employ nanomaterials such as gold nanoparticles to construct electrodes which can transfer the biological reactions more efficiently, or attempt to obtain enhanced signal through multi-labeled carriers or utilize enzyme mimics to catalyze redox cycling. This review discusses recent advances in signal amplification methods and their applications. Critical assessment of each method is also considered.
2021, 32(5): 1603-1614
doi: 10.1016/j.cclet.2020.11.073
Abstract:
In the past few years, photo-crosslinkable hydrogels have drawn a great attention in tissue engineering applications due to their high biocompatibility and extracellular matrix (ECM)-like structure. They can be easily biofabricated through exposure of a photosensitive system composed of photo-crosslinkable hydrogels, photo-initiators and other compounds such as cells and therapeutic molecules, to ultraviolet or visible light. With the development of biofabrication methods, many researchers studied the biological applications of photo-crosslinkable hydrogels in tissue engineering, such as vascular, wound dressing and bone engineering. This review highlights the biomaterials for photo-crosslinkable hydrogels, biofabrication techniques and their biological applications in tissue engineering. Meanwhile, the challenges and prospects of photo-crosslinkable hydrogels are discussed as well.
In the past few years, photo-crosslinkable hydrogels have drawn a great attention in tissue engineering applications due to their high biocompatibility and extracellular matrix (ECM)-like structure. They can be easily biofabricated through exposure of a photosensitive system composed of photo-crosslinkable hydrogels, photo-initiators and other compounds such as cells and therapeutic molecules, to ultraviolet or visible light. With the development of biofabrication methods, many researchers studied the biological applications of photo-crosslinkable hydrogels in tissue engineering, such as vascular, wound dressing and bone engineering. This review highlights the biomaterials for photo-crosslinkable hydrogels, biofabrication techniques and their biological applications in tissue engineering. Meanwhile, the challenges and prospects of photo-crosslinkable hydrogels are discussed as well.
2021, 32(5): 1615-1625
doi: 10.1016/j.cclet.2021.01.001
Abstract:
The stimulator of interferon genes (STING) shows promising clinical activity in infectious diseases and tumors. However, the lack of targeting capability and intracellular stability of STING agonists severely limits the therapeutic efficacy. Recently, drug delivery systems (DDSs) overcome these delivery barriers of STING agonists via passive or active cell targeting, prolonged blood circulation and drug release, and lysosome escape, etc. In this review, we will describe in detail how existing DDSs are designed to overcome delivery barriers and activate the STING pathway, and the current biomedical applications of STING-activating DDSs in the treatments of infectious diseases and tumors. Finally, the prospects and challenges of DDSs in STING activation are discussed.
The stimulator of interferon genes (STING) shows promising clinical activity in infectious diseases and tumors. However, the lack of targeting capability and intracellular stability of STING agonists severely limits the therapeutic efficacy. Recently, drug delivery systems (DDSs) overcome these delivery barriers of STING agonists via passive or active cell targeting, prolonged blood circulation and drug release, and lysosome escape, etc. In this review, we will describe in detail how existing DDSs are designed to overcome delivery barriers and activate the STING pathway, and the current biomedical applications of STING-activating DDSs in the treatments of infectious diseases and tumors. Finally, the prospects and challenges of DDSs in STING activation are discussed.
2021, 32(5): 1626-1636
doi: 10.1016/j.cclet.2020.10.026
Abstract:
The carbon nanotubes (CNTs) as the emerging materials for organic pollutant removal have gradually become a burgeoning research field. Herein, a mini-review of CNTs-based materials currently studies for organic pollutant elimination is presented. This review summarizes the preparation methods of CNTs-based materials. CNTs-based materials can be used as adsorbents to remove organic pollutants in wastewater. The adsorption mechanisms mainly include surface diffusion, pore diffusion and adsorption reaction. Most importantly, an in-depth overview of CNTs-based materials currently available in advanced oxidation processes (AOPs) applications for wastewater treatment is proposed. CNTs-based materials can catalyze different oxidants (e.g., hydrogen peroxide (H2O2), persulfates (PMS/PDS), ozone (O3) and ferrate/permanganate (Fe(VI)/Mn(VII)) to generate more reactive oxygen species (ROS) for organic pollutant elimination. Moreover, the possible reaction mechanisms of removing organic pollutants by CNTs-based materials are summarized systematically and discussed in detail. Finally, application potential and future research directions of CNTs-based materials in the environmental remediation field are proposed.
The carbon nanotubes (CNTs) as the emerging materials for organic pollutant removal have gradually become a burgeoning research field. Herein, a mini-review of CNTs-based materials currently studies for organic pollutant elimination is presented. This review summarizes the preparation methods of CNTs-based materials. CNTs-based materials can be used as adsorbents to remove organic pollutants in wastewater. The adsorption mechanisms mainly include surface diffusion, pore diffusion and adsorption reaction. Most importantly, an in-depth overview of CNTs-based materials currently available in advanced oxidation processes (AOPs) applications for wastewater treatment is proposed. CNTs-based materials can catalyze different oxidants (e.g., hydrogen peroxide (H2O2), persulfates (PMS/PDS), ozone (O3) and ferrate/permanganate (Fe(VI)/Mn(VII)) to generate more reactive oxygen species (ROS) for organic pollutant elimination. Moreover, the possible reaction mechanisms of removing organic pollutants by CNTs-based materials are summarized systematically and discussed in detail. Finally, application potential and future research directions of CNTs-based materials in the environmental remediation field are proposed.
2021, 32(5): 1637-1644
doi: 10.1016/j.cclet.2021.02.057
Abstract:
Clean production, as an important part of green chemistry, has received great attention and considerable development in recent years. In this perspective article, we summarized some examples of (nearly) quantitative synthesis, clean separation and purification to emphasize clean production. These reactions were carried out by using eco-friendly solvents and the pure products could be easily obtained through clean procedures.
Clean production, as an important part of green chemistry, has received great attention and considerable development in recent years. In this perspective article, we summarized some examples of (nearly) quantitative synthesis, clean separation and purification to emphasize clean production. These reactions were carried out by using eco-friendly solvents and the pure products could be easily obtained through clean procedures.
2021, 32(5): 1645-1652
doi: 10.1016/j.cclet.2021.01.002
Abstract:
The RAS/mitogen-activated protein kinase (MAPK) pathway disorder induced by the missense mutations in the tyrosine-protein phosphatase non-receptor type 11 (PTPN11) gene which resulted in the non-receptor protein tyrosine phosphatase SHP2 dysfunction has been reported in many lung cancer cases. Moreover, the Src homology region 2 (SH2)-containing protein tyrosine phosphatase 2 (SHP2) mutation or deletion triggers multiple signaling pathway dysfunctions including RAS/MAPK, RAS/extracellular-signal-regulated kinase (ERK), phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT), Janus kinase/signal transducers and activators of transcription (JAK/STAT) and Hippo/yes-associated protein (YAP) which affect the expression of growth factors, cytokines and hormones. In recent years, the developing of the small molecule SHP2 inhibitors received a lot of attention. In this review, we summarize the recent years' progresses of the SHP2 inhibitors development for the lung cancer treatment.
The RAS/mitogen-activated protein kinase (MAPK) pathway disorder induced by the missense mutations in the tyrosine-protein phosphatase non-receptor type 11 (PTPN11) gene which resulted in the non-receptor protein tyrosine phosphatase SHP2 dysfunction has been reported in many lung cancer cases. Moreover, the Src homology region 2 (SH2)-containing protein tyrosine phosphatase 2 (SHP2) mutation or deletion triggers multiple signaling pathway dysfunctions including RAS/MAPK, RAS/extracellular-signal-regulated kinase (ERK), phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT), Janus kinase/signal transducers and activators of transcription (JAK/STAT) and Hippo/yes-associated protein (YAP) which affect the expression of growth factors, cytokines and hormones. In recent years, the developing of the small molecule SHP2 inhibitors received a lot of attention. In this review, we summarize the recent years' progresses of the SHP2 inhibitors development for the lung cancer treatment.
2021, 32(5): 1653-1656
doi: 10.1016/j.cclet.2021.01.005
Abstract:
In this paper, we demonstrate that modification of anion-transport active 1, 3-bis(benzimidazol-2-yl) benzene with strongly electron-withdrawing trifluoromethyl and nitro groups leads to a dramatic increase in the anionophoric activity, and the activity may be greatly regulated by the curvatures of the liposomes used.
In this paper, we demonstrate that modification of anion-transport active 1, 3-bis(benzimidazol-2-yl) benzene with strongly electron-withdrawing trifluoromethyl and nitro groups leads to a dramatic increase in the anionophoric activity, and the activity may be greatly regulated by the curvatures of the liposomes used.
2021, 32(5): 1657-1659
doi: 10.1016/j.cclet.2020.11.067
Abstract:
A pair of neolignan enantiomers with an unprecedented carbon skeleton, (+)-/(—)-angelignanine [(+)-/(—)-1], was isolated as minor components of an aqueous extract of the Angelica sinensis root heads (guitou). Their structures were determined by spectroscopic data analysis and the absolute configurations were assigned by the circular dichroism (CD) exciton chirality method as well as electronic CD quantum calculations. The enantiomers represent the first 2, 7'-cyclo-8, 9'-neolignans, of which biosynthetic pathways originating from precursors ferulic acid and coniferyl alcohol is proposed. In an in vivo test, both the enantiomers showed significant hypnotic effects at a dose of 10 mg/kg (i.g.).
A pair of neolignan enantiomers with an unprecedented carbon skeleton, (+)-/(—)-angelignanine [(+)-/(—)-1], was isolated as minor components of an aqueous extract of the Angelica sinensis root heads (guitou). Their structures were determined by spectroscopic data analysis and the absolute configurations were assigned by the circular dichroism (CD) exciton chirality method as well as electronic CD quantum calculations. The enantiomers represent the first 2, 7'-cyclo-8, 9'-neolignans, of which biosynthetic pathways originating from precursors ferulic acid and coniferyl alcohol is proposed. In an in vivo test, both the enantiomers showed significant hypnotic effects at a dose of 10 mg/kg (i.g.).
2021, 32(5): 1660-1664
doi: 10.1016/j.cclet.2020.12.023
Abstract:
Antimalarial chemotherapies endowed with effectiveness against drug-resistant parasites and good safety are urgently required in clinical. Our previous research revealed that clinical phase Ⅱ antitumor drug Quisinostat was a promising antimalarial prototype by inhibiting the activity of Plasmodium falciparum (P. falciparum) histone deacetylase (PfHDAC). Herein, 30 novel spirocyclic linker derivatives were designed and synthesized based on Quisinostat as lead compound, and then their antimalarial activities and cytotoxicity were systematically evaluated. Among them, compounds 8 and 27 could effectively eliminate wild-type and multi-drug resistant P. falciparum parasites, and display weakened cytotoxicity and good metabolic stability. Western blot assay demonstrated that they could inhibit PfHDAC activity like Quisinostat. In addition, both 8 and 27 showed certain antimalarial efficacy in rodent malaria model, and the animal toxicity of 8 was significantly improved compared with Quisinostat. Overall, 8 and 27 were structurally novel PfHDAC inhibitors and provided prospective prototype for further antimalarial drug research.
Antimalarial chemotherapies endowed with effectiveness against drug-resistant parasites and good safety are urgently required in clinical. Our previous research revealed that clinical phase Ⅱ antitumor drug Quisinostat was a promising antimalarial prototype by inhibiting the activity of Plasmodium falciparum (P. falciparum) histone deacetylase (PfHDAC). Herein, 30 novel spirocyclic linker derivatives were designed and synthesized based on Quisinostat as lead compound, and then their antimalarial activities and cytotoxicity were systematically evaluated. Among them, compounds 8 and 27 could effectively eliminate wild-type and multi-drug resistant P. falciparum parasites, and display weakened cytotoxicity and good metabolic stability. Western blot assay demonstrated that they could inhibit PfHDAC activity like Quisinostat. In addition, both 8 and 27 showed certain antimalarial efficacy in rodent malaria model, and the animal toxicity of 8 was significantly improved compared with Quisinostat. Overall, 8 and 27 were structurally novel PfHDAC inhibitors and provided prospective prototype for further antimalarial drug research.
2021, 32(5): 1665-1668
doi: 10.1016/j.cclet.2020.11.019
Abstract:
A novel good water-soluble macrocycle containing two pyridinium moieties was synthesized in high yield. It could form 1:1 complexes with neutral guests containing naphthalene or phenyl units in water. The water-soluble macrocycle can selectively encapsulate naphthalene to form a 1:1 complex over a variety of polycyclic aromatic hydrocarbons.
A novel good water-soluble macrocycle containing two pyridinium moieties was synthesized in high yield. It could form 1:1 complexes with neutral guests containing naphthalene or phenyl units in water. The water-soluble macrocycle can selectively encapsulate naphthalene to form a 1:1 complex over a variety of polycyclic aromatic hydrocarbons.
2021, 32(5): 1669-1674
doi: 10.1016/j.cclet.2020.12.013
Abstract:
Nowadays, the development of triplet-involved materials becomes a hot research topic in solid-state luminescence fields. However, the mechanism of triplet-involved emission still remains some mysteries to conquer. Here, we proposed a new concept of excited-state conformation capture for the constructions of different types of triplet-involved materials. Firstly, excited-state conformation could be trapped by supramolecular chains in crystal and form a new optimum excited-state structure which is different from that in solution or simple rigid environment, leading to bright thermally activated delayed fluorescence (TADF) emission. Based on excited-state conformation capture methodology, next, we obtained room-temperature phosphorescence (RTP) by introducing Br atoms for the enhancement of intersystem crossing. It could be concluded from experimental results that TADF may originate from aggregate effect while RTP may derive from monomers. Finally, heavy-atom free RTP and ultra RTP were achieved by eliminating aggregate effect. This work could not only extend the design methodology of triplet-involved materials but also set clear evidences for the mechanism of triplet-involved emissions.
Nowadays, the development of triplet-involved materials becomes a hot research topic in solid-state luminescence fields. However, the mechanism of triplet-involved emission still remains some mysteries to conquer. Here, we proposed a new concept of excited-state conformation capture for the constructions of different types of triplet-involved materials. Firstly, excited-state conformation could be trapped by supramolecular chains in crystal and form a new optimum excited-state structure which is different from that in solution or simple rigid environment, leading to bright thermally activated delayed fluorescence (TADF) emission. Based on excited-state conformation capture methodology, next, we obtained room-temperature phosphorescence (RTP) by introducing Br atoms for the enhancement of intersystem crossing. It could be concluded from experimental results that TADF may originate from aggregate effect while RTP may derive from monomers. Finally, heavy-atom free RTP and ultra RTP were achieved by eliminating aggregate effect. This work could not only extend the design methodology of triplet-involved materials but also set clear evidences for the mechanism of triplet-involved emissions.
2021, 32(5): 1675-1678
doi: 10.1016/j.cclet.2021.02.039
Abstract:
Polypeptoids have been explored as mimics of polypeptides, owing to polypeptoids' superior stability upon proteolysis. Polypeptoids can be synthesized from one-pot ring-opening polymerization of amino acid N-substituted N-carboxyanhydrides (NNCAs). However, the speed of polymerization of NNCAs can be very slow, especially for NNCAs bearing a bulky N-substitution group. This hindered the exploration on polypeptoids with more diverse structures and functions. Therefore, it is in great need to develop advanced strategies that can accelerate the polymerization on inactive NNCAs. Hereby, we report that lithium/sodium/potassium hexamethyldisilazide (Li/Na/KHMDS) initiates a substantially faster poly-merization on NNCAs than do commonly used amine initiators, especially for NNCAs with bulky N-substitution group. This fast NNCA polymerization will increase the structure diversity and application of polypeptoids as synthetic mimics of polypeptides.
Polypeptoids have been explored as mimics of polypeptides, owing to polypeptoids' superior stability upon proteolysis. Polypeptoids can be synthesized from one-pot ring-opening polymerization of amino acid N-substituted N-carboxyanhydrides (NNCAs). However, the speed of polymerization of NNCAs can be very slow, especially for NNCAs bearing a bulky N-substitution group. This hindered the exploration on polypeptoids with more diverse structures and functions. Therefore, it is in great need to develop advanced strategies that can accelerate the polymerization on inactive NNCAs. Hereby, we report that lithium/sodium/potassium hexamethyldisilazide (Li/Na/KHMDS) initiates a substantially faster poly-merization on NNCAs than do commonly used amine initiators, especially for NNCAs with bulky N-substitution group. This fast NNCA polymerization will increase the structure diversity and application of polypeptoids as synthetic mimics of polypeptides.
2021, 32(5): 1679-1682
doi: 10.1016/j.cclet.2020.11.068
Abstract:
An unprecedented tunable hydrophobic effect in self-assembly of a small cationic organic fluorophore (NI-TPy+)-based with aggregation-induced emission (AIE) property was realized in aqueous solution. The amplification of hydrophobicity was found to be significantly dependent upon the increasing aggregates of NI-TPy+, which enabled the study of the hydrophobic binding of chaotropic anions with the Hofmeister series.
An unprecedented tunable hydrophobic effect in self-assembly of a small cationic organic fluorophore (NI-TPy+)-based with aggregation-induced emission (AIE) property was realized in aqueous solution. The amplification of hydrophobicity was found to be significantly dependent upon the increasing aggregates of NI-TPy+, which enabled the study of the hydrophobic binding of chaotropic anions with the Hofmeister series.
2021, 32(5): 1683-1686
doi: 10.1016/j.cclet.2020.12.024
Abstract:
A convenient synthetic protocol for the hexasubstituted benzene derivatives was successfully developed by DABCO promoted domino reaction of arylidene malononitrile with two molecules of dialkyl but-2-ynedioates. The domino reaction resulted in tetraalkyl 6-cyano-[1, 1'-biphenyl]-2, 3, 4, 5-tetracarboxylates in good to high yields. This formal [2 + 2 + 2] cycloaddition was believed to proceed with sequential nucleophilic addition, Michael addition, annulation and aromatization processes.
A convenient synthetic protocol for the hexasubstituted benzene derivatives was successfully developed by DABCO promoted domino reaction of arylidene malononitrile with two molecules of dialkyl but-2-ynedioates. The domino reaction resulted in tetraalkyl 6-cyano-[1, 1'-biphenyl]-2, 3, 4, 5-tetracarboxylates in good to high yields. This formal [2 + 2 + 2] cycloaddition was believed to proceed with sequential nucleophilic addition, Michael addition, annulation and aromatization processes.
2021, 32(5): 1687-1690
doi: 10.1016/j.cclet.2021.02.038
Abstract:
Aggregation-induced emission luminogens (AIEgens) have been used in biomacromolecules detection. Herein, TPE-dC and TPE-dU acted as the nucleoside-based AIEgens sensors in the first case, which can be used to detect ctDNA and rRNA in vitro and light up the nucleus in vivo depending on the intermolecular binding affinity. This AIE process enables the quantitative analysis or visualization of nucleic acids in solution or gels state, respectively. Furthermore, confocal laser scanning microscopy (CLSM) images of L929 cells stained with TPE-dC or TPE-dU clearly shows that nucleoside-based AIEgens bio-probes can pass the cell membranes to reach the cell nucleus, without cytotoxicity at the imaging condition (incubation time > 12 h, and 10 μmol/L of concentration). Since the nucleus is rich in DNA/RNA, fluorescence turn-on mode has a great potential in nucleus imaging and clinical diagnosis.
Aggregation-induced emission luminogens (AIEgens) have been used in biomacromolecules detection. Herein, TPE-dC and TPE-dU acted as the nucleoside-based AIEgens sensors in the first case, which can be used to detect ctDNA and rRNA in vitro and light up the nucleus in vivo depending on the intermolecular binding affinity. This AIE process enables the quantitative analysis or visualization of nucleic acids in solution or gels state, respectively. Furthermore, confocal laser scanning microscopy (CLSM) images of L929 cells stained with TPE-dC or TPE-dU clearly shows that nucleoside-based AIEgens bio-probes can pass the cell membranes to reach the cell nucleus, without cytotoxicity at the imaging condition (incubation time > 12 h, and 10 μmol/L of concentration). Since the nucleus is rich in DNA/RNA, fluorescence turn-on mode has a great potential in nucleus imaging and clinical diagnosis.
2021, 32(5): 1691-1695
doi: 10.1016/j.cclet.2020.12.028
Abstract:
Herein, we designed and constructed two metallacycles, 1 and 2, to illustrate the conformational effect of isomeric AIE fluorophores on the platform of supramolecular coordination complexes (SCCs). Specifically, the dangling phenyl rings in TPE units of the metallacycle 1 align completely outside the main cyclic structure, while in the metallacycle 2, these phenyl rings align half inside and half outside. The experimental results showed that two metallacycles exhibited different behaviors in terms of AIE fluorescence and chemical sensing, which could be attributed to the subtle structural difference of the TPE units. This work represents the unification of topics such as self-assembly, AIE, and chemical sensing, and further promotes the understanding for the structure-property relationship of isomeric AIE fluorophores.
Herein, we designed and constructed two metallacycles, 1 and 2, to illustrate the conformational effect of isomeric AIE fluorophores on the platform of supramolecular coordination complexes (SCCs). Specifically, the dangling phenyl rings in TPE units of the metallacycle 1 align completely outside the main cyclic structure, while in the metallacycle 2, these phenyl rings align half inside and half outside. The experimental results showed that two metallacycles exhibited different behaviors in terms of AIE fluorescence and chemical sensing, which could be attributed to the subtle structural difference of the TPE units. This work represents the unification of topics such as self-assembly, AIE, and chemical sensing, and further promotes the understanding for the structure-property relationship of isomeric AIE fluorophores.
2021, 32(5): 1696-1700
doi: 10.1016/j.cclet.2020.12.026
Abstract:
A green tandem reaction, including insertion/aerobic oxidation/bisindolylation, starting from indoles and diazo compounds has been developed. The combination of water and fluorinated alcohol plays dual roles as solvent and promoter in this chemical transformation. Molecular oxygen in the air acts as an oxidant. 3, 3'-Bis(indolyl)methanes with quaternary carbon were produced under metal-free conditions. No any catalyst and additive were required. N2 and water were released as sole by-products. Absence of water and fluorinated alcohol resulted in Wolff rearrangement product.
A green tandem reaction, including insertion/aerobic oxidation/bisindolylation, starting from indoles and diazo compounds has been developed. The combination of water and fluorinated alcohol plays dual roles as solvent and promoter in this chemical transformation. Molecular oxygen in the air acts as an oxidant. 3, 3'-Bis(indolyl)methanes with quaternary carbon were produced under metal-free conditions. No any catalyst and additive were required. N2 and water were released as sole by-products. Absence of water and fluorinated alcohol resulted in Wolff rearrangement product.
2021, 32(5): 1701-1704
doi: 10.1016/j.cclet.2020.12.047
Abstract:
Since the discovery of left-handed G-quadruplex (L-G4) structure formed by natural DNA, there has been a growing interest in its potential functions. This study utilised it to catalyse enantioselective Diels-Alder reactions, considering its different optical rotation compared to an ordinary G4. It was determined that when L-G4 was used with a combination of copper(Ⅱ) ions, there was a good enantioselectivity (-52% ee) without further addition of ligands. When further consideration was given by adding G4 ligands, G4 was further stabilised, even obtaining a better enantioselectivity (up to -80% ee). Moreover, when using ligands that have regulatory effects on G4, the ee value can be adjusted. In this work, a minimal left-handed G4 was reported. A follow-up study was also conducted, which recovers that the minimal left-handed G4 remains its catalytic effect and enantioselectivity, but is not so effective as the former case. This indicates that a complete G4 structure is relatively conducive to chiral catalysis.
Since the discovery of left-handed G-quadruplex (L-G4) structure formed by natural DNA, there has been a growing interest in its potential functions. This study utilised it to catalyse enantioselective Diels-Alder reactions, considering its different optical rotation compared to an ordinary G4. It was determined that when L-G4 was used with a combination of copper(Ⅱ) ions, there was a good enantioselectivity (-52% ee) without further addition of ligands. When further consideration was given by adding G4 ligands, G4 was further stabilised, even obtaining a better enantioselectivity (up to -80% ee). Moreover, when using ligands that have regulatory effects on G4, the ee value can be adjusted. In this work, a minimal left-handed G4 was reported. A follow-up study was also conducted, which recovers that the minimal left-handed G4 remains its catalytic effect and enantioselectivity, but is not so effective as the former case. This indicates that a complete G4 structure is relatively conducive to chiral catalysis.
2021, 32(5): 1705-1708
doi: 10.1016/j.cclet.2020.12.046
Abstract:
An efficient approach to sulfur-bridged imidazopyridines has been developed under metal-free conditions using inexpensive sulfur powder as the sulfur source. Most appealingly, the reaction can proceed smoothly without addition of any additives, ultimately decreasing the production of chemical waste. The inexpensive and green method should provide a useful strategy for constructing a library of novel and biological interesting heteroaromatic sulfides.
An efficient approach to sulfur-bridged imidazopyridines has been developed under metal-free conditions using inexpensive sulfur powder as the sulfur source. Most appealingly, the reaction can proceed smoothly without addition of any additives, ultimately decreasing the production of chemical waste. The inexpensive and green method should provide a useful strategy for constructing a library of novel and biological interesting heteroaromatic sulfides.
2021, 32(5): 1709-1712
doi: 10.1016/j.cclet.2020.12.027
Abstract:
Rhodium(Ⅲ)-catalyzed [4 + 1] cyclization of azobenzenes with α-Cl ketones has been developed. 3-Acyl-2H-indazoles could be easily afforded in up to 97% yields for more than 30 examples. The obtained products are potentially valuable in organic synthesis and drug discovery. This protocol featured with high efficiency, extensive functional group tolerance and mild reaction conditions. The one-step efficient construction of an anti-inflammatory agent confirms the practicability of this procedure.
Rhodium(Ⅲ)-catalyzed [4 + 1] cyclization of azobenzenes with α-Cl ketones has been developed. 3-Acyl-2H-indazoles could be easily afforded in up to 97% yields for more than 30 examples. The obtained products are potentially valuable in organic synthesis and drug discovery. This protocol featured with high efficiency, extensive functional group tolerance and mild reaction conditions. The one-step efficient construction of an anti-inflammatory agent confirms the practicability of this procedure.
2021, 32(5): 1713-1716
doi: 10.1016/j.cclet.2021.01.018
Abstract:
Fused indolizidines and quinolizidines are important skeletons in a variety of natural products and pharmacologically important compounds. A one-pot tandem route from amide to fused indolizidines and quinolizidines is disclosed. This method is conducted in mild conditions and shows well tolerance of functional groups. It is also easy to be scaled up to gram scale and can be applied smoothly to the total synthesis of alkaloids such as (±)-crispine A, (±)-xylopinine, (±)-desbromoarborescidine A, (±)-harmicine and other bioactive substances.
Fused indolizidines and quinolizidines are important skeletons in a variety of natural products and pharmacologically important compounds. A one-pot tandem route from amide to fused indolizidines and quinolizidines is disclosed. This method is conducted in mild conditions and shows well tolerance of functional groups. It is also easy to be scaled up to gram scale and can be applied smoothly to the total synthesis of alkaloids such as (±)-crispine A, (±)-xylopinine, (±)-desbromoarborescidine A, (±)-harmicine and other bioactive substances.
2021, 32(5): 1717-1720
doi: 10.1016/j.cclet.2021.01.024
Abstract:
An electron-deficient [CpERhCl2]2 catalyzed annulation of N-pentafluorophenylbenzamides with internal alkynes was successfully established under mild reaction conditions, with the assistance of Lewis acid silver salt. Particularly, electron-deficient benzamide substrates were smoothly transformed into the desired products in this catalytic system. The catalytic system showed a broad tolerance for different substituents on the aromatic rings or aryl, alkyl-substituted alkynes.
An electron-deficient [CpERhCl2]2 catalyzed annulation of N-pentafluorophenylbenzamides with internal alkynes was successfully established under mild reaction conditions, with the assistance of Lewis acid silver salt. Particularly, electron-deficient benzamide substrates were smoothly transformed into the desired products in this catalytic system. The catalytic system showed a broad tolerance for different substituents on the aromatic rings or aryl, alkyl-substituted alkynes.
2021, 32(5): 1721-1725
doi: 10.1016/j.cclet.2020.11.028
Abstract:
Three sesquiterpene-based meroterpenoids psiguamers A–C (1–3) with new skeletons were isolated from Psidium guajava leaves. Compounds (±)-1 and (±)-2 were two pairs of humulene-derived meroterpenoids bearing a rare methylated benzoylphloroglucinol unit, while 3 was an unprecedented adduct of bicyclogermacrene and methylated benzoylphloroglucinol. Their structures were determined based on comprehensive analyses of spectroscopic data, calculated electronic circular dichroism (ECD) spectra, total synthesis, and X-ray crystallographic data. The biomimetic synthesis of (±)-1 and (±)-2 was achieved. Compound (+)-1 exhibited cytotoxic activities against five human tumor cell lines (HCT-116, HepG2, BGC-823, A549, and U251), with IC50 values of 2.94, 9.01, 6.45, 5.42, and 5.33 μmol/L, respectively.
Three sesquiterpene-based meroterpenoids psiguamers A–C (1–3) with new skeletons were isolated from Psidium guajava leaves. Compounds (±)-1 and (±)-2 were two pairs of humulene-derived meroterpenoids bearing a rare methylated benzoylphloroglucinol unit, while 3 was an unprecedented adduct of bicyclogermacrene and methylated benzoylphloroglucinol. Their structures were determined based on comprehensive analyses of spectroscopic data, calculated electronic circular dichroism (ECD) spectra, total synthesis, and X-ray crystallographic data. The biomimetic synthesis of (±)-1 and (±)-2 was achieved. Compound (+)-1 exhibited cytotoxic activities against five human tumor cell lines (HCT-116, HepG2, BGC-823, A549, and U251), with IC50 values of 2.94, 9.01, 6.45, 5.42, and 5.33 μmol/L, respectively.
2021, 32(5): 1726-1730
doi: 10.1016/j.cclet.2020.11.072
Abstract:
Pathological detection using immunohistochemistry (IHC) has become an indispensable process in the diagnosis confirmation of various cancers. However, the production of monoclonal antibodies is always very complex, expensive and time-consuming, and the batch differences are significant due to the corporeity and health statuses of animals may be different. In this work, an aptamer-based histochemistry (aptahistochemistry) assay was developed using a DNA aptamer for specific diagnosis of clinical breast cancer tissue sections. This aptahistochemistry assay can specifically distinguish Luminal A breast cancer molecular subtype from Luminal B (HER2+), HER2-enriched, and triple-negative breast cancer molecular subtypes, as well as para-carcinoma tissue, mastitis tissue and normal breast tissue. The accuracy of this aptahistochemistry assay for the diagnosis of Luminal A breast cancer was as high as 80%, which showed a great potential for clinical pathological diagnosis applications.
Pathological detection using immunohistochemistry (IHC) has become an indispensable process in the diagnosis confirmation of various cancers. However, the production of monoclonal antibodies is always very complex, expensive and time-consuming, and the batch differences are significant due to the corporeity and health statuses of animals may be different. In this work, an aptamer-based histochemistry (aptahistochemistry) assay was developed using a DNA aptamer for specific diagnosis of clinical breast cancer tissue sections. This aptahistochemistry assay can specifically distinguish Luminal A breast cancer molecular subtype from Luminal B (HER2+), HER2-enriched, and triple-negative breast cancer molecular subtypes, as well as para-carcinoma tissue, mastitis tissue and normal breast tissue. The accuracy of this aptahistochemistry assay for the diagnosis of Luminal A breast cancer was as high as 80%, which showed a great potential for clinical pathological diagnosis applications.
2021, 32(5): 1731-1736
doi: 10.1016/j.cclet.2020.12.005
Abstract:
Particles administrated intravenously will pass through the pulmonary capillary network before being distributed to the body. Therefore, fabrication of vectors sensitive to blood shear and active with blood components should be a practical approach to develop lung-targeting gene carriers self-regulated by circulatory system. In this work, we designed a series of cationic peptides with the same charge density but varying hydrophobicity and capacity to form hydrogen bonds, and investigated their ability to form complexes with siRNA, the behaviours of peptide/siRNA complexes in the presence of serum under shear, and the lung-targeting efficacy of the complexes regulated by blood. The hydrophobic interaction controls the complexation between peptide and siRNA, while the hydrogen bonds are responsible for the binding of peptides to the serum components in blood. In vivo tests show that all the peptide/siRNA complexes can accumulate in lung. However, only the complexes that exhibit weak interaction with serum components and can be broken down by shear avoid the inflammation and death caused by pulmonary embolism. Moreover, the peptide with strong hydrophobicity can retain siRNA in lung without early release of the cargo. Our study provides a step toward the development of adaptive gene carriers under the regulation of circulatory system.
Particles administrated intravenously will pass through the pulmonary capillary network before being distributed to the body. Therefore, fabrication of vectors sensitive to blood shear and active with blood components should be a practical approach to develop lung-targeting gene carriers self-regulated by circulatory system. In this work, we designed a series of cationic peptides with the same charge density but varying hydrophobicity and capacity to form hydrogen bonds, and investigated their ability to form complexes with siRNA, the behaviours of peptide/siRNA complexes in the presence of serum under shear, and the lung-targeting efficacy of the complexes regulated by blood. The hydrophobic interaction controls the complexation between peptide and siRNA, while the hydrogen bonds are responsible for the binding of peptides to the serum components in blood. In vivo tests show that all the peptide/siRNA complexes can accumulate in lung. However, only the complexes that exhibit weak interaction with serum components and can be broken down by shear avoid the inflammation and death caused by pulmonary embolism. Moreover, the peptide with strong hydrophobicity can retain siRNA in lung without early release of the cargo. Our study provides a step toward the development of adaptive gene carriers under the regulation of circulatory system.
2021, 32(5): 1737-1742
doi: 10.1016/j.cclet.2020.12.006
Abstract:
The last few decades have witnessed the emergence of a very large variety of engineered nanomaterials. However, it is far from to meet the growing clinical demand. Actually, nature itself is an excellent nanotechnologist, and provides us with a range of wonderful materials, from inorganic particles found in non-life bodies to biofilms, like platelets, erythrocyte membranes, produced by many bacteria or cells. These nanomaterials are entirely natural, and not surprisingly, there is a growing interest in the development of natural nanoproducts. Native components-inspired biomaterials have gained considerable attention owing to their safety and functions. In this study, egg white was developed as drug carrier to load PTX by a green and simple one-pot method, and systematic characterization was completed. The results indicated that PTX@EW NPs possess excellent biocompatibility, enhanced tumor targeting capability, effectively reducing the toxic side effects of PTX. The obviously enhanced antitumor effect further confirmed EW was a highly prospective biomaterial in the nano-carrier industry.
The last few decades have witnessed the emergence of a very large variety of engineered nanomaterials. However, it is far from to meet the growing clinical demand. Actually, nature itself is an excellent nanotechnologist, and provides us with a range of wonderful materials, from inorganic particles found in non-life bodies to biofilms, like platelets, erythrocyte membranes, produced by many bacteria or cells. These nanomaterials are entirely natural, and not surprisingly, there is a growing interest in the development of natural nanoproducts. Native components-inspired biomaterials have gained considerable attention owing to their safety and functions. In this study, egg white was developed as drug carrier to load PTX by a green and simple one-pot method, and systematic characterization was completed. The results indicated that PTX@EW NPs possess excellent biocompatibility, enhanced tumor targeting capability, effectively reducing the toxic side effects of PTX. The obviously enhanced antitumor effect further confirmed EW was a highly prospective biomaterial in the nano-carrier industry.
2021, 32(5): 1743-1746
doi: 10.1016/j.cclet.2020.12.034
Abstract:
Quaternary ammonium salts (QASs) are excellent candidates for treating stubborn bacterial infections caused by biofilms due to their high sterilization efficiency and potential inhibition of the development of drug resistance. However, the inherent toxicity of QASs, including cytotoxicity, protein absorption and hemolysis, severely limits their applications in vivo. Herein, a charge-convertible quaternary ammonium salt-based micelle (QAS-SL@CM) was constructed by co-assembly of two amphiphiles with opposite charges and shell cross-linking strategy. The toxicity of the QAS-SL@CM could be greatly reduced towards human cells contrast to the corresponding QASs. By response to the acidic environment at infection sites, the surface charge of QAS-SL@CM could be immediately changed to positive and then target to negatively charged bacteria. Furthermore, β-thiopropionate bonds on QAS-SL@CM could also be disintegrated under acid environment to release QASs to kill bacteria. Importantly, the QAS-SL@CM showed significant therapeutic effect in mice subcutaneous abscesses models without interference with normal cells. Therefore, a surface adaptive micelle constructed by charge-convertible strategy has been developed to overcome the cytotoxicity of QASs, and could intelligently respond to the microenvironment of infected wound for in vivo infection therapy, which shows promising application in clinic.
Quaternary ammonium salts (QASs) are excellent candidates for treating stubborn bacterial infections caused by biofilms due to their high sterilization efficiency and potential inhibition of the development of drug resistance. However, the inherent toxicity of QASs, including cytotoxicity, protein absorption and hemolysis, severely limits their applications in vivo. Herein, a charge-convertible quaternary ammonium salt-based micelle (QAS-SL@CM) was constructed by co-assembly of two amphiphiles with opposite charges and shell cross-linking strategy. The toxicity of the QAS-SL@CM could be greatly reduced towards human cells contrast to the corresponding QASs. By response to the acidic environment at infection sites, the surface charge of QAS-SL@CM could be immediately changed to positive and then target to negatively charged bacteria. Furthermore, β-thiopropionate bonds on QAS-SL@CM could also be disintegrated under acid environment to release QASs to kill bacteria. Importantly, the QAS-SL@CM showed significant therapeutic effect in mice subcutaneous abscesses models without interference with normal cells. Therefore, a surface adaptive micelle constructed by charge-convertible strategy has been developed to overcome the cytotoxicity of QASs, and could intelligently respond to the microenvironment of infected wound for in vivo infection therapy, which shows promising application in clinic.
2021, 32(5): 1747-1750
doi: 10.1016/j.cclet.2021.01.008
Abstract:
The improvement in accuracy of in vitro diagnosis has always been the focus of early screening of thyroid dysfunction. We constructed a microfluidic chip based on a polystyrene polymer substrate. Total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3), free thyroxine (FT4), and thyrotropin (TSH) in human whole blood samples were analysed by fluorescence immunoassay to evaluate thyroid function. The results indicate that the microfluidic chip shows a good linear relationship in the detection of TT3, TT4, FT3, FT4, and TSH standards, and the correlation coefficient (r) is not less than 0.9900. In addition, the chip also has strong anti-interference (RSD% ≤ 5%) and good repeatability (CV ≤ 8%), and its inter-batch differences are small (CV ≤ 15%). The results of practical application in clinical thyroid function measurement indicated its high accuracy (r ≥ 0.9900). It provides a new method for the determination of thyroid function and lays a foundation for subsequent clinical application.
The improvement in accuracy of in vitro diagnosis has always been the focus of early screening of thyroid dysfunction. We constructed a microfluidic chip based on a polystyrene polymer substrate. Total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3), free thyroxine (FT4), and thyrotropin (TSH) in human whole blood samples were analysed by fluorescence immunoassay to evaluate thyroid function. The results indicate that the microfluidic chip shows a good linear relationship in the detection of TT3, TT4, FT3, FT4, and TSH standards, and the correlation coefficient (r) is not less than 0.9900. In addition, the chip also has strong anti-interference (RSD% ≤ 5%) and good repeatability (CV ≤ 8%), and its inter-batch differences are small (CV ≤ 15%). The results of practical application in clinical thyroid function measurement indicated its high accuracy (r ≥ 0.9900). It provides a new method for the determination of thyroid function and lays a foundation for subsequent clinical application.
2021, 32(5): 1751-1754
doi: 10.1016/j.cclet.2020.12.008
Abstract:
Although the antitumor drug cabazitaxel shows great therapeutic potential, its high toxicity and poor water solubility limit its utility. However, the use of stimuli-responsive prodrugs is a promising strategy for overcoming these limitations. Herein, we report the synthesis of two highly water soluble, acid-sensitive PEGylated acyclic-ketal-linked cabazitaxel prodrugs (PKCs) with improved antitumor efficacy. In an acidic tumor microenvironment, the PKCs hydrolyzed rapidly to release the native drug, whereas they were stable in the normal physiological environment. Compared with cabazitaxel injection, the PKCs had much higher maximum tolerated doses; and in an MDA-MB-231 subcutaneous xenograft nude mouse model, the PKCs showed better antitumor efficacy and safety than cabazitaxel injection. The prodrug strategy reported herein could be useful for the development of other water soluble, acid-sensitive prodrugs with improved efficacy.
Although the antitumor drug cabazitaxel shows great therapeutic potential, its high toxicity and poor water solubility limit its utility. However, the use of stimuli-responsive prodrugs is a promising strategy for overcoming these limitations. Herein, we report the synthesis of two highly water soluble, acid-sensitive PEGylated acyclic-ketal-linked cabazitaxel prodrugs (PKCs) with improved antitumor efficacy. In an acidic tumor microenvironment, the PKCs hydrolyzed rapidly to release the native drug, whereas they were stable in the normal physiological environment. Compared with cabazitaxel injection, the PKCs had much higher maximum tolerated doses; and in an MDA-MB-231 subcutaneous xenograft nude mouse model, the PKCs showed better antitumor efficacy and safety than cabazitaxel injection. The prodrug strategy reported herein could be useful for the development of other water soluble, acid-sensitive prodrugs with improved efficacy.
2021, 32(5): 1755-1758
doi: 10.1016/j.cclet.2020.12.033
Abstract:
Fragrances are frequently added to a variety of products, including food, cosmetics and health products. However, the high volatility and instability of essence limit its application in some fields. In this study, mesoporous silica nanoparticles (MSNs) were prepared to encapsulate eugenol, which could reduce the volatilization of the fragrance molecules. A facile approach was presented to synthesize MSNs with three different pore diameters for encapsulating eugenol. In addition, the properties of MSNs including mean particle size, morphology, encapsulating efficiency and release tendency were characterized. Results showed that the larger the pore diameters of MSNs, the more aromatic molecules were adsorbed. Furthermore, the release mechanism was described as the smaller the pore diameters of MSNs, the slower the release of eugenol.
Fragrances are frequently added to a variety of products, including food, cosmetics and health products. However, the high volatility and instability of essence limit its application in some fields. In this study, mesoporous silica nanoparticles (MSNs) were prepared to encapsulate eugenol, which could reduce the volatilization of the fragrance molecules. A facile approach was presented to synthesize MSNs with three different pore diameters for encapsulating eugenol. In addition, the properties of MSNs including mean particle size, morphology, encapsulating efficiency and release tendency were characterized. Results showed that the larger the pore diameters of MSNs, the more aromatic molecules were adsorbed. Furthermore, the release mechanism was described as the smaller the pore diameters of MSNs, the slower the release of eugenol.
2021, 32(5): 1759-1764
doi: 10.1016/j.cclet.2020.12.004
Abstract:
The increasing incidence of osteoarthritis (OA) seriously affects life quality, posing a huge socioeconomic burden. Tissue engineering technology has become a hot topic in articular cartilage repair as one of the key treatment methods to alleviate OA. Hydrogel, one of the most commonly used scaffold materials, can provide a good extracellular matrix microenvironment for seed cells such as bone marrow mesenchymal stem cells (BMSCs), which can promote cartilage regeneration. However, the low homing rate of stem cells severely limits their role in promoting articular cartilage regeneration. Stromal cell-derived factor- 1α (SDF-1α) plays a crucial role in the activation, mobilization, homing, and migration of MSCs. Herein, a novel injectable chemotaxis hydrogel, composed of chitosan-based injectable hydrogel and embedding SDF-1α-loaded nanodroplets (PFP@NDs-PEG-SDF-1α) was designed and fabricated. The ultrasound was then used to augment the injectable chemotaxis hydrogel and promote the homing migration of BMSCs for OA cartilage repair. The effect of ultrasound augmenting injectable PFP@NDs-PEG-SDF-1α/hydrogel on the migration of BMSCs was verified in vitro and in vivo, which remarkably promotes stem cell homing and the repair of cartilage in the OA model. Therefore, the treatment strategy of ultrasound augmenting injectable chemotaxis hydrogel has a bright potential for OA articular cartilage repair.
The increasing incidence of osteoarthritis (OA) seriously affects life quality, posing a huge socioeconomic burden. Tissue engineering technology has become a hot topic in articular cartilage repair as one of the key treatment methods to alleviate OA. Hydrogel, one of the most commonly used scaffold materials, can provide a good extracellular matrix microenvironment for seed cells such as bone marrow mesenchymal stem cells (BMSCs), which can promote cartilage regeneration. However, the low homing rate of stem cells severely limits their role in promoting articular cartilage regeneration. Stromal cell-derived factor- 1α (SDF-1α) plays a crucial role in the activation, mobilization, homing, and migration of MSCs. Herein, a novel injectable chemotaxis hydrogel, composed of chitosan-based injectable hydrogel and embedding SDF-1α-loaded nanodroplets (PFP@NDs-PEG-SDF-1α) was designed and fabricated. The ultrasound was then used to augment the injectable chemotaxis hydrogel and promote the homing migration of BMSCs for OA cartilage repair. The effect of ultrasound augmenting injectable PFP@NDs-PEG-SDF-1α/hydrogel on the migration of BMSCs was verified in vitro and in vivo, which remarkably promotes stem cell homing and the repair of cartilage in the OA model. Therefore, the treatment strategy of ultrasound augmenting injectable chemotaxis hydrogel has a bright potential for OA articular cartilage repair.
2021, 32(5): 1765-1769
doi: 10.1016/j.cclet.2020.11.058
Abstract:
Nanomaterial based drug delivery system have received great attention in clinical application due to their high therapeutic efficacy and lower side effects than classical method, multi-functional nanomaterial also have shown the excellent performance at cancer theranostic and durg tracking in vivo and in vitro. However, most of these works are influenced by the bio-toxicity of applied nanomaterials, which could influence the diagnostic results and treatment effect. Therefore, we have prepared a high biocompatibility porous carbon nanospheres (PCNs) based nano-system (PCN-siRNA-DOX-FA) for targeted drug delivery and theranostic. The surface modifications have increased dispersion and stability of the PCNs, and folic acid (FA) had enhanced the active target ability for FA receptor positive cell lines. Moreover, through the siRNA structure and doxorubicin (DOX) loading, biological and chemical combined multi-therapy was achieved in cancerous cells. This constructed nano-system could positively improve the biotoxicity problem of nanomaterial and provide a potential platform for clinical cancer theranostic applications.
Nanomaterial based drug delivery system have received great attention in clinical application due to their high therapeutic efficacy and lower side effects than classical method, multi-functional nanomaterial also have shown the excellent performance at cancer theranostic and durg tracking in vivo and in vitro. However, most of these works are influenced by the bio-toxicity of applied nanomaterials, which could influence the diagnostic results and treatment effect. Therefore, we have prepared a high biocompatibility porous carbon nanospheres (PCNs) based nano-system (PCN-siRNA-DOX-FA) for targeted drug delivery and theranostic. The surface modifications have increased dispersion and stability of the PCNs, and folic acid (FA) had enhanced the active target ability for FA receptor positive cell lines. Moreover, through the siRNA structure and doxorubicin (DOX) loading, biological and chemical combined multi-therapy was achieved in cancerous cells. This constructed nano-system could positively improve the biotoxicity problem of nanomaterial and provide a potential platform for clinical cancer theranostic applications.
2021, 32(5): 1770-1774
doi: 10.1016/j.cclet.2020.12.055
Abstract:
Despite of the promising achievements of immune checkpoints blockade therapy (ICB) in the clinic, which was often limited by low objective responses and severe side effects. Herein, we explored a synergistic strategy to combine in situ vaccination and gene-mediated anti-PD therapy, which was generated by unmethylated cytosine-phosphate-guanine (CpG) and pshPD-L1 gene co-delivery. PEI worked as the delivery carrier to co-deliver the CpG and pshPD-L1 genes, the formed PDC (PEI/DNA/CpG) nanoparticles were further shielded by aldehyde modified polyethylene glycol (OHC-PEG-CHO) via pH responsive Schiff base reaction for OHC-PEG-CHO-PEI/DNA/CpG nanoparticles (P(PDC) NPs) preparation. All steps could be finished within 30 min. Such simple nanoparticles achieved the synergistic antitumor efficacy in B16F10 tumor-bearing mice, and the amplified T cell responses, together with enhanced NK cells infiltration were observed after the combined treatments. In addition, the pH responsive delivery system reduced the side effects triggered by anti-PD therapy. The facile and effective combination strategy we presented here might provide a novel treatment for tumor inhibition.
Despite of the promising achievements of immune checkpoints blockade therapy (ICB) in the clinic, which was often limited by low objective responses and severe side effects. Herein, we explored a synergistic strategy to combine in situ vaccination and gene-mediated anti-PD therapy, which was generated by unmethylated cytosine-phosphate-guanine (CpG) and pshPD-L1 gene co-delivery. PEI worked as the delivery carrier to co-deliver the CpG and pshPD-L1 genes, the formed PDC (PEI/DNA/CpG) nanoparticles were further shielded by aldehyde modified polyethylene glycol (OHC-PEG-CHO) via pH responsive Schiff base reaction for OHC-PEG-CHO-PEI/DNA/CpG nanoparticles (P(PDC) NPs) preparation. All steps could be finished within 30 min. Such simple nanoparticles achieved the synergistic antitumor efficacy in B16F10 tumor-bearing mice, and the amplified T cell responses, together with enhanced NK cells infiltration were observed after the combined treatments. In addition, the pH responsive delivery system reduced the side effects triggered by anti-PD therapy. The facile and effective combination strategy we presented here might provide a novel treatment for tumor inhibition.
2021, 32(5): 1775-1779
doi: 10.1016/j.cclet.2020.12.058
Abstract:
Recently, stimuli-responsive DNA nanostructure-based nanodevices have been applied for cancer therapy. In this study, pH-responsive i-motif DNA was modified on gold nanoparticles (AuNPs) via a facile, time-saving freeze-thaw method and utilized to construct stimuli-responsive drug nanocarriers. When the environment pH changes from 7.4 to 5.0, the i-motif DNA would be folded into four-stranded (C-quadruplex) that could be characterized by circular dichroism, and the characteristic of acid stimulate was verified by fluorescence resonance energy transfer (FRET). To enhance specifical cellular uptake, MUC1 aptamer was employed as the targeting moiety. Doxorubicin (Dox) is an anticancer drug that can be efficiently intercalated into GC base pairs of DNA nanostructure to form drug-loaded nanovehicles (Dox@AuNP-MUC1). Additionally, owing to the excellent photothermal conversion efficiency of AuNPs, the synergistic effect between chemotherapy and PTT can be readily achieved by 808 nm near-infrared (NIR) irradiation, which exhibits specifically and efficiently anticancer efficiency. Hence, this multifunctional drug carrier shows the potential for synergistic photothermal-chemotherapy.
Recently, stimuli-responsive DNA nanostructure-based nanodevices have been applied for cancer therapy. In this study, pH-responsive i-motif DNA was modified on gold nanoparticles (AuNPs) via a facile, time-saving freeze-thaw method and utilized to construct stimuli-responsive drug nanocarriers. When the environment pH changes from 7.4 to 5.0, the i-motif DNA would be folded into four-stranded (C-quadruplex) that could be characterized by circular dichroism, and the characteristic of acid stimulate was verified by fluorescence resonance energy transfer (FRET). To enhance specifical cellular uptake, MUC1 aptamer was employed as the targeting moiety. Doxorubicin (Dox) is an anticancer drug that can be efficiently intercalated into GC base pairs of DNA nanostructure to form drug-loaded nanovehicles (Dox@AuNP-MUC1). Additionally, owing to the excellent photothermal conversion efficiency of AuNPs, the synergistic effect between chemotherapy and PTT can be readily achieved by 808 nm near-infrared (NIR) irradiation, which exhibits specifically and efficiently anticancer efficiency. Hence, this multifunctional drug carrier shows the potential for synergistic photothermal-chemotherapy.
2021, 32(5): 1780-1784
doi: 10.1016/j.cclet.2020.12.041
Abstract:
Traditional colorimetric glucose biosensor generally involves complex assay procedures. Free labile enzymes and peroxidase substrates are used separately for triggering a chromogenic reaction. These limits result in inferior enzyme stability and defective enzymatic catalytic efficiency, making it hard to routinely utilize them for the direct and fast test of glucose. In this work, we provide an all-inclusive substrates/enzymes nanoparticle employed 3, 3'5, 5'-tetramethylbenzidine (TMB) as chromogenic substrates and glucose oxidase (GOx)/horseradish peroxidase (HRP) as signal amplifier enzymes (TMB-GH NPs) by the molecule self-assembly technique. The "all-inclusive" nanoparticles can realize the tandem colorimetric reactions, and the oxidation product of TMB (ox-TMB) exhibits a strong NIR laser-driven photothermal effect, thus allowing quantitative photothermal detection of glucose. Owing to the restriction of the molecular motion of GOx, HRP, and TMB, the distance of mass transfer between substrates was shortened largely, leading to improved catalytic activity for glucose. Overall, our strategy will simplify the analysis procedure, furthermore, these integrated nanoparticles not only display higher stability and activity than that of the free GOx/HRP system and possesses an excellent performance for colorimetric and photothermal bioassay of glucose simultaneously. We believe that this unique technique will give good inspirations to develop simple and precise methods for bioassay.
Traditional colorimetric glucose biosensor generally involves complex assay procedures. Free labile enzymes and peroxidase substrates are used separately for triggering a chromogenic reaction. These limits result in inferior enzyme stability and defective enzymatic catalytic efficiency, making it hard to routinely utilize them for the direct and fast test of glucose. In this work, we provide an all-inclusive substrates/enzymes nanoparticle employed 3, 3'5, 5'-tetramethylbenzidine (TMB) as chromogenic substrates and glucose oxidase (GOx)/horseradish peroxidase (HRP) as signal amplifier enzymes (TMB-GH NPs) by the molecule self-assembly technique. The "all-inclusive" nanoparticles can realize the tandem colorimetric reactions, and the oxidation product of TMB (ox-TMB) exhibits a strong NIR laser-driven photothermal effect, thus allowing quantitative photothermal detection of glucose. Owing to the restriction of the molecular motion of GOx, HRP, and TMB, the distance of mass transfer between substrates was shortened largely, leading to improved catalytic activity for glucose. Overall, our strategy will simplify the analysis procedure, furthermore, these integrated nanoparticles not only display higher stability and activity than that of the free GOx/HRP system and possesses an excellent performance for colorimetric and photothermal bioassay of glucose simultaneously. We believe that this unique technique will give good inspirations to develop simple and precise methods for bioassay.
2021, 32(5): 1785-1789
doi: 10.1016/j.cclet.2020.12.053
Abstract:
Tyrosinase (TYR) is an important polyphenolic oxidase enzyme and usually regards as a biomarker of melanoma cancer. Highly effective tracking TYR activity in vivo will help to study the mechanism of TYR in living organisms and forecasts related diseases. In this study, we present a novel TYR-activatable fluorescent probe (CHMC-DOPA) for tracking TYR activity in vitro and in vivo. CHMC-DOPA is constructed by incorporating dopamine (DOPA) moiety into a fluorescent chloro-hydroxyl-merocyanine (CHMC) scaffold. Upon exposure to TYR, the dopamine unit in CHMC-DOPA is oxidized to a dopaquinone derivative, and an intramolecular photo-induced electron transfer (PET) process between CHMC fluorophore and o-dopaquinone will take place, the fluorescence of CHMC-DOPA is quenched rapidly. Therefore, the evaluation of TYR activity is established in terms of the relationship between fluorescence quenching efficiency and TYR activity. In our experiments, CHMC-DOPA shows various advantages, such as fast response (8 min), low concentration of TYR activation (0.5 U/mL), good water-solubility, as well as the lowest detection limit (0.003 U/mL) compared with previously reported works. Furthermore, CHMC-DOPA also exhibits excellent cell membrane permeability and low cytotoxicity, which is successfully used to monitor endogenous TYR activity in living cancer cells and zebrafish models. CHMC-DOPA performs well, and we anticipate that this newly designed novel platform will provide an alternative for high effective monitoring TYR activity in biosystems.
Tyrosinase (TYR) is an important polyphenolic oxidase enzyme and usually regards as a biomarker of melanoma cancer. Highly effective tracking TYR activity in vivo will help to study the mechanism of TYR in living organisms and forecasts related diseases. In this study, we present a novel TYR-activatable fluorescent probe (CHMC-DOPA) for tracking TYR activity in vitro and in vivo. CHMC-DOPA is constructed by incorporating dopamine (DOPA) moiety into a fluorescent chloro-hydroxyl-merocyanine (CHMC) scaffold. Upon exposure to TYR, the dopamine unit in CHMC-DOPA is oxidized to a dopaquinone derivative, and an intramolecular photo-induced electron transfer (PET) process between CHMC fluorophore and o-dopaquinone will take place, the fluorescence of CHMC-DOPA is quenched rapidly. Therefore, the evaluation of TYR activity is established in terms of the relationship between fluorescence quenching efficiency and TYR activity. In our experiments, CHMC-DOPA shows various advantages, such as fast response (8 min), low concentration of TYR activation (0.5 U/mL), good water-solubility, as well as the lowest detection limit (0.003 U/mL) compared with previously reported works. Furthermore, CHMC-DOPA also exhibits excellent cell membrane permeability and low cytotoxicity, which is successfully used to monitor endogenous TYR activity in living cancer cells and zebrafish models. CHMC-DOPA performs well, and we anticipate that this newly designed novel platform will provide an alternative for high effective monitoring TYR activity in biosystems.
2021, 32(5): 1790-1794
doi: 10.1016/j.cclet.2020.12.031
Abstract:
Understanding the physical mechanisms governing aggregation-induced-emission (AIE) and aggregation-caused-quenching plays a vital role in developing functional AIE materials. In this work, tetraphenylethene (TPE, a classical AIEgen) and naphthalimide (NI, a popular fluorophore with ACQ characteristics) were connected through non-conjugated linkages and conjugated linkages. We showed that the nonconjugated-linkage of TPE to NI fragments leads to substantial PET in molecular aggregates and ACQ. In contrast, the conjugated connection between TPE and NI moieties results in the AIE phenomenon by suppressing twisted intramolecular charge transfer. This work provides an important guideline for the rational design of AIE materials.
Understanding the physical mechanisms governing aggregation-induced-emission (AIE) and aggregation-caused-quenching plays a vital role in developing functional AIE materials. In this work, tetraphenylethene (TPE, a classical AIEgen) and naphthalimide (NI, a popular fluorophore with ACQ characteristics) were connected through non-conjugated linkages and conjugated linkages. We showed that the nonconjugated-linkage of TPE to NI fragments leads to substantial PET in molecular aggregates and ACQ. In contrast, the conjugated connection between TPE and NI moieties results in the AIE phenomenon by suppressing twisted intramolecular charge transfer. This work provides an important guideline for the rational design of AIE materials.
2021, 32(5): 1795-1798
doi: 10.1016/j.cclet.2020.12.039
Abstract:
The reactive oxygen species (ROS) are tightly associated with endoplasmic reticulum (ER) stress. Thus, the deep and visual insight of aberrant ROS fluctuations in the ER can help us better investigate the ER stress-associated pathology. In this work, a fluorescent probe ERC for HOCl detection in the ER based on phenothiazine-derived coumarin platform was developed. In the presence of HOCl, ERC exhibited an emission change from 609 nm to 503 nm within seconds. It also showed high sensitivity (0.44 μmol/L) and superb photostability. Significantly, ERC displayed low cytotoxicity, good cell membrane permeability, and appreciable ER-targetability. Ultimately, the probe was successfully utilized to image exogenous and endogenous HOCl in living cells and reveal the HOCl burst in cisplatin-treated cancer cells.
The reactive oxygen species (ROS) are tightly associated with endoplasmic reticulum (ER) stress. Thus, the deep and visual insight of aberrant ROS fluctuations in the ER can help us better investigate the ER stress-associated pathology. In this work, a fluorescent probe ERC for HOCl detection in the ER based on phenothiazine-derived coumarin platform was developed. In the presence of HOCl, ERC exhibited an emission change from 609 nm to 503 nm within seconds. It also showed high sensitivity (0.44 μmol/L) and superb photostability. Significantly, ERC displayed low cytotoxicity, good cell membrane permeability, and appreciable ER-targetability. Ultimately, the probe was successfully utilized to image exogenous and endogenous HOCl in living cells and reveal the HOCl burst in cisplatin-treated cancer cells.
2021, 32(5): 1799-1802
doi: 10.1016/j.cclet.2020.12.044
Abstract:
Based on 4-bromo-1, 8-naphthalic anhydride, one novel ratiometric fluorescence H2S-probe (IDNA) was designed and synthesized. Further studies indicate that IDNA can sensitively recognize H2S (detection limit of 7 μmol/L) with good selectivity and anti-interference ability. In addition, IDNA has satisfactory photostability in HeLa cells, ability of mitochondrial co-localization, and can be utilized in fluorescence imaging of H2S.
Based on 4-bromo-1, 8-naphthalic anhydride, one novel ratiometric fluorescence H2S-probe (IDNA) was designed and synthesized. Further studies indicate that IDNA can sensitively recognize H2S (detection limit of 7 μmol/L) with good selectivity and anti-interference ability. In addition, IDNA has satisfactory photostability in HeLa cells, ability of mitochondrial co-localization, and can be utilized in fluorescence imaging of H2S.
2021, 32(5): 1803-1808
doi: 10.1016/j.cclet.2020.12.012
Abstract:
Autophagy plays a vital role in maintaining the balance of normal physiological state of living cells. In this paper, a polarity-specific two-photon fluorescent probe Lyso-NA based on naphthalimide was synthesized for the purpose of monitoring autophagy during biological research. The results of photophysical properties and theoretical calculation confirmed that different polarities of solvents mainly effected fluorescent intensities of probe. Fluorescent intensity, quantum yield and fluorescence lifetime of probe kept a good linear relationship with polarity respectively. In addition, due to its low toxicity and selective accumulation in lysosomes, Lyso-NA is suitable for detecting changes in lysosomal polarity of living cells. Compare with the imaging results of plasmid transfection, a better performed real-time long-term fluorescent visualization of autophagy in living cells was achieved. Probe Lyso-NA can work as an efficient and cost effective imaging tool for visualizing autophagy in living cells.
Autophagy plays a vital role in maintaining the balance of normal physiological state of living cells. In this paper, a polarity-specific two-photon fluorescent probe Lyso-NA based on naphthalimide was synthesized for the purpose of monitoring autophagy during biological research. The results of photophysical properties and theoretical calculation confirmed that different polarities of solvents mainly effected fluorescent intensities of probe. Fluorescent intensity, quantum yield and fluorescence lifetime of probe kept a good linear relationship with polarity respectively. In addition, due to its low toxicity and selective accumulation in lysosomes, Lyso-NA is suitable for detecting changes in lysosomal polarity of living cells. Compare with the imaging results of plasmid transfection, a better performed real-time long-term fluorescent visualization of autophagy in living cells was achieved. Probe Lyso-NA can work as an efficient and cost effective imaging tool for visualizing autophagy in living cells.
2021, 32(5): 1809-1813
doi: 10.1016/j.cclet.2020.12.029
Abstract:
We constructed a reaction-based near-infrared fluorescent probe (Niap) to specifically identify alkaline phosphatase (ALP) with fast red fluorescence enhancement. Based on the positive concentration-dependent manner between the fluorescent intensity of the Niap and ALP, probe Niap was used to study the ALP enrichment and variation in golden apple snails (Pomacea canaliculata) exposed to the molluscicide candidate PPU06. After treatment with different concentrations of PPU06 over various times, three organs of the surviving snails, liver, stomach and plantaris, were frozen and sectioned for fluorescent imaging experiments. With increased PPU06 concentration, red fluorescence substantially increased in the liver and reached a maximum within 24 h when the PPU06 concentration was 0.75 mg/L. No obvious changes in the stomach or foot plantaris were found. It showed PPU06 caused liver injury and stimulated the increase of ALP in the liver of P. canaliculata. This study demonstrates a rapid ALP fluorescent identification method that can be used to study the effects of PPU06 on P. canaliculata. It also provides optical evidence that may aid in the discovery of new chemistry for snail control.
We constructed a reaction-based near-infrared fluorescent probe (Niap) to specifically identify alkaline phosphatase (ALP) with fast red fluorescence enhancement. Based on the positive concentration-dependent manner between the fluorescent intensity of the Niap and ALP, probe Niap was used to study the ALP enrichment and variation in golden apple snails (Pomacea canaliculata) exposed to the molluscicide candidate PPU06. After treatment with different concentrations of PPU06 over various times, three organs of the surviving snails, liver, stomach and plantaris, were frozen and sectioned for fluorescent imaging experiments. With increased PPU06 concentration, red fluorescence substantially increased in the liver and reached a maximum within 24 h when the PPU06 concentration was 0.75 mg/L. No obvious changes in the stomach or foot plantaris were found. It showed PPU06 caused liver injury and stimulated the increase of ALP in the liver of P. canaliculata. This study demonstrates a rapid ALP fluorescent identification method that can be used to study the effects of PPU06 on P. canaliculata. It also provides optical evidence that may aid in the discovery of new chemistry for snail control.
2021, 32(5): 1814-1818
doi: 10.1016/j.cclet.2020.11.026
Abstract:
Acetaminophen (ACE) is commonly used in analgesic and antipyretic drug, which is hardly removed by traditional wastewater treatment processes. Herein, amorphous Co(OH)2 nanocages were explored as peroxymonosulfate (PMS) activator for efficient degradation of ACE. In the presence of amorphous Co(OH)2 nanocages, 100% of ACE removal was reached within 2 min with a reaction rate constant k1 = 3.68 min-1 at optimum pH 5, which was much better than that of crystalline β-Co(OH)2 and Co3O4. Amorphous materials (disorder atom arrangement) with hollow structures possess large specific surface area, more reactive sites, and abundant vacancies structures, which could efficiently facilitate the catalytic redox reactions. The radicals quenching experiment demonstrated that SO4·- radicals dominated the ACE degradation rather than ·OH radicals. The mechanism of ACE degradation was elucidated by the analysis of degradation intermediates and theoretical calculation, indicating that the electrophilic SO4·- and ·OH tend to attack the atoms of ACE with high Fukui index (f-). Our finding highlights the remarkable advantages of amorphous materials as heterogeneous catalysts in sulfate radicals-based AOPs and sheds new lights on water treatment for the degradation of emerging organic contaminants.
Acetaminophen (ACE) is commonly used in analgesic and antipyretic drug, which is hardly removed by traditional wastewater treatment processes. Herein, amorphous Co(OH)2 nanocages were explored as peroxymonosulfate (PMS) activator for efficient degradation of ACE. In the presence of amorphous Co(OH)2 nanocages, 100% of ACE removal was reached within 2 min with a reaction rate constant k1 = 3.68 min-1 at optimum pH 5, which was much better than that of crystalline β-Co(OH)2 and Co3O4. Amorphous materials (disorder atom arrangement) with hollow structures possess large specific surface area, more reactive sites, and abundant vacancies structures, which could efficiently facilitate the catalytic redox reactions. The radicals quenching experiment demonstrated that SO4·- radicals dominated the ACE degradation rather than ·OH radicals. The mechanism of ACE degradation was elucidated by the analysis of degradation intermediates and theoretical calculation, indicating that the electrophilic SO4·- and ·OH tend to attack the atoms of ACE with high Fukui index (f-). Our finding highlights the remarkable advantages of amorphous materials as heterogeneous catalysts in sulfate radicals-based AOPs and sheds new lights on water treatment for the degradation of emerging organic contaminants.
2021, 32(5): 1819-1822
doi: 10.1016/j.cclet.2020.11.023
Abstract:
A Zn-containing graphite carbon (Zn-GC) with uniform Zn metal sites and hierarchical pore structure was obtained by pyrolysis of Zn-based metal organic framework (MOF). Zn-GC exhibited excellent adsorption capacity and reproducibility for formaldehyde. The adsorption capacity of Zn-GC was 736 times that of commercial activated carbon and 5.6 times that of ZSM-5 adsorbents. The characterization and experimental results showed that the surface chemical characteristics of the adsorption material play an important role in the adsorption performance. The superior performance was attributed to Zn metal sites and oxygen-containing functional groups on the MOF derivative as well as hierarchical pore structure. The material showed a great potential in the field of organic pollutant removal.
A Zn-containing graphite carbon (Zn-GC) with uniform Zn metal sites and hierarchical pore structure was obtained by pyrolysis of Zn-based metal organic framework (MOF). Zn-GC exhibited excellent adsorption capacity and reproducibility for formaldehyde. The adsorption capacity of Zn-GC was 736 times that of commercial activated carbon and 5.6 times that of ZSM-5 adsorbents. The characterization and experimental results showed that the surface chemical characteristics of the adsorption material play an important role in the adsorption performance. The superior performance was attributed to Zn metal sites and oxygen-containing functional groups on the MOF derivative as well as hierarchical pore structure. The material showed a great potential in the field of organic pollutant removal.
2021, 32(5): 1823-1826
doi: 10.1016/j.cclet.2020.11.010
Abstract:
Maximizing adsorption and catalytic active sites and promoting the photo-excited charge separation are two key factors to achieve excellent photocatalytic performance. In this study, we report a sol-gel synthesis approach to obtain non-metal doped TiO2 with sponge-like structure and surface-phase junctions all at once. While doping of carbon and nitrogen shifted the activation wavelength to the visible-light region, the innovative use of perchloric acid as a pore-making agent led to the formation of three-dimensional lamellar and porous structure with surface-phase junctions. High surface area with catalytic active sites rendered by the sponge-like structure and surface-phase junctions contributed to the much improved photocatalytic degradation efficiency toward rhodamine B, tetracycline and Disperse Red 60 with excellent reusability and stability. The improved generation and separation efficiency of the photo-induced charge carriers of the as-prepared TiO2 were supported by electrochemical impedance measurements and transient photocurrent responses. This method could also be applied to other photocatalysts to achieve structural alteration and element doping simultaneously.
Maximizing adsorption and catalytic active sites and promoting the photo-excited charge separation are two key factors to achieve excellent photocatalytic performance. In this study, we report a sol-gel synthesis approach to obtain non-metal doped TiO2 with sponge-like structure and surface-phase junctions all at once. While doping of carbon and nitrogen shifted the activation wavelength to the visible-light region, the innovative use of perchloric acid as a pore-making agent led to the formation of three-dimensional lamellar and porous structure with surface-phase junctions. High surface area with catalytic active sites rendered by the sponge-like structure and surface-phase junctions contributed to the much improved photocatalytic degradation efficiency toward rhodamine B, tetracycline and Disperse Red 60 with excellent reusability and stability. The improved generation and separation efficiency of the photo-induced charge carriers of the as-prepared TiO2 were supported by electrochemical impedance measurements and transient photocurrent responses. This method could also be applied to other photocatalysts to achieve structural alteration and element doping simultaneously.
2021, 32(5): 1827-1830
doi: 10.1016/j.cclet.2020.11.031
Abstract:
Exosomes have attracted widespread interest due to their inherent advantages in tumor diagnosis and treatment monitoring. However, it is still a big challenge for highly sensitive and specific detection of exosome in real complexed samples. Herein, a molecular recognition triggered aptazyme cascade strategy was developed for ultrasensitive detection of cancer exosomes in clinical serum samples. In this design, one target exosome could capture a large quantity of aptazymes for the first-step signal amplification. And then the captured aptazyme was activated and recycled to release the fluorophore-abelled substrate strand for a cascaded signal amplification. Notably, the activation of aptazyme only occurs when it has bound with target exosome, ensuring a low background. The experimental results show that the limit of detection (LOD) and the limit of quantification (LOQ) are 3.5×103 particles/μL and 1.7×104 particles/μL, respectively, which is comparable to the results of most existed fluorescence-based exosome probes. Moreover, this assay possesses high specificity to distinguish exosomes derived from other cell lines. Furthermore, this fluorescence probe was utilized in cancer patient and healthy serum samples successfully, suggesting its great potential for clinical diagnosis and biological studies.
Exosomes have attracted widespread interest due to their inherent advantages in tumor diagnosis and treatment monitoring. However, it is still a big challenge for highly sensitive and specific detection of exosome in real complexed samples. Herein, a molecular recognition triggered aptazyme cascade strategy was developed for ultrasensitive detection of cancer exosomes in clinical serum samples. In this design, one target exosome could capture a large quantity of aptazymes for the first-step signal amplification. And then the captured aptazyme was activated and recycled to release the fluorophore-abelled substrate strand for a cascaded signal amplification. Notably, the activation of aptazyme only occurs when it has bound with target exosome, ensuring a low background. The experimental results show that the limit of detection (LOD) and the limit of quantification (LOQ) are 3.5×103 particles/μL and 1.7×104 particles/μL, respectively, which is comparable to the results of most existed fluorescence-based exosome probes. Moreover, this assay possesses high specificity to distinguish exosomes derived from other cell lines. Furthermore, this fluorescence probe was utilized in cancer patient and healthy serum samples successfully, suggesting its great potential for clinical diagnosis and biological studies.
