Login In
2018 Volume 34 Issue 2
2018, 34(2):
Abstract:
2018, 34(2): 113-114
doi: 10.3866/PKU.WHXB201707101
Abstract:
2018, 34(2): 115-116
doi: 10.3866/PKU.WHXB201707102
Abstract:
2018, 34(2): 117-118
doi: 10.3866/PKU.WHXB201707191
Abstract:
2018, 34(2): 119-120
doi: 10.3866/PKU.WHXB201707192
Abstract:
2018, 34(2): 121-122
doi: 10.3866/PKU.WHXB201707261
Abstract:
2018, 34(2): 123-139
doi: 10.3866/PKU.WHXB201707042
Abstract:
Multifunctional theranostic agents that are responsive to external physical stimuli such as light,magnetic field,ultrasound,radiofrequency,and X-rays have been widely explored for their use in physical stimulus-responsive therapies for cancer.Encouraging results in many preclinical animal experiments have been obtained;thus,this innovative strategy has gained great attention.Owing to the nontoxicity of physical stimulus-responsive agents and treatment specificity under particular external stimuli,physical stimulus-responsive cancer therapies provide greatly reduced toxicity and enhanced therapeutic efficiency compared with conventional chemotherapeutic agents.When combining physical stimulus-responsive therapies with other traditional therapeutics,synergistic antitumor effects via various mechanisms can be achieved.In this review,we will summarize the recent developments in physical stimulus-responsive therapies and discuss the important roles of nanoscale theranostic agents in these novel treatment modalities.
Multifunctional theranostic agents that are responsive to external physical stimuli such as light,magnetic field,ultrasound,radiofrequency,and X-rays have been widely explored for their use in physical stimulus-responsive therapies for cancer.Encouraging results in many preclinical animal experiments have been obtained;thus,this innovative strategy has gained great attention.Owing to the nontoxicity of physical stimulus-responsive agents and treatment specificity under particular external stimuli,physical stimulus-responsive cancer therapies provide greatly reduced toxicity and enhanced therapeutic efficiency compared with conventional chemotherapeutic agents.When combining physical stimulus-responsive therapies with other traditional therapeutics,synergistic antitumor effects via various mechanisms can be achieved.In this review,we will summarize the recent developments in physical stimulus-responsive therapies and discuss the important roles of nanoscale theranostic agents in these novel treatment modalities.
2018, 34(2): 140-167
doi: 10.3866/PKU.WHXB201707174
Abstract:
Radiation therapy kills tumor cells via focused high energy radiation, and has become one of the most common and effective clinical treatments for malignant tumors. However, some limitations restrict its clinical efficacy, including a requirement for elevated doses of radiation, side effects due to exposure of healthy tissue, and especially radioresistance of tumor cells. With the development of nanomedicine, multifunctional nanoradiosensitizers offer a new route to improve the efficiency of radiation therapy. In this paper, we summarize the main types of nanoradiosensitizers and their applications in radiation therapy, especially those that have currently entered clinical trials. We also summarize the main approaches to nanomaterials-based radiosensitization, and discuss the factors influencing their application. Finally, the challenges and prospects of multifunctional nanoradiosensitizers are presented.
Radiation therapy kills tumor cells via focused high energy radiation, and has become one of the most common and effective clinical treatments for malignant tumors. However, some limitations restrict its clinical efficacy, including a requirement for elevated doses of radiation, side effects due to exposure of healthy tissue, and especially radioresistance of tumor cells. With the development of nanomedicine, multifunctional nanoradiosensitizers offer a new route to improve the efficiency of radiation therapy. In this paper, we summarize the main types of nanoradiosensitizers and their applications in radiation therapy, especially those that have currently entered clinical trials. We also summarize the main approaches to nanomaterials-based radiosensitization, and discuss the factors influencing their application. Finally, the challenges and prospects of multifunctional nanoradiosensitizers are presented.
Thermodynamics of the Hydrothermal Decomposition Reaction of Potassic Syenite with Zeolite Formation
2018, 34(2): 168-176
doi: 10.3866/PKU.WHXB201707111
Abstract:
The thermodynamics of hydrothermal decomposition reaction of potassic syenite,collected from Anhui province,China,with the formation of zeolites was studied in this work.The phase equilibrium model of the potassic syenite-NaOH-H2O hydrothermal system was constructed by the combination of "mixed solvent electrolyte model" and thermodynamic data of mineral end-members,as well as zeolites species,which was calculated from the"polymer model".According to the Gibbs free energy of reaction,the decomposition of potassic syenite into hydroxycancrinite,analcime,zeolite P,and zeolite A occurs spontaneously within the temperature range of 160-300℃.The formation conditions of hydroxycancrinite and analcime were predicted from the simulation of phase equilibrium by OLI Analyzer 9.3 software.After experimental verification,analcime (regular tetragonal trisoctahedron,~50 μm) and hydroxycancrinite (columnar crystals,~20 μm in length,500 nm-1 μm in diameters) were respectively obtained with >97% K2O leaching.
The thermodynamics of hydrothermal decomposition reaction of potassic syenite,collected from Anhui province,China,with the formation of zeolites was studied in this work.The phase equilibrium model of the potassic syenite-NaOH-H2O hydrothermal system was constructed by the combination of "mixed solvent electrolyte model" and thermodynamic data of mineral end-members,as well as zeolites species,which was calculated from the"polymer model".According to the Gibbs free energy of reaction,the decomposition of potassic syenite into hydroxycancrinite,analcime,zeolite P,and zeolite A occurs spontaneously within the temperature range of 160-300℃.The formation conditions of hydroxycancrinite and analcime were predicted from the simulation of phase equilibrium by OLI Analyzer 9.3 software.After experimental verification,analcime (regular tetragonal trisoctahedron,~50 μm) and hydroxycancrinite (columnar crystals,~20 μm in length,500 nm-1 μm in diameters) were respectively obtained with >97% K2O leaching.
2018, 34(2): 177-184
doi: 10.3866/PKU.WHXB201707121
Abstract:
Control over the ligand surface density provides an accurate molecular basis for the quantitative study of biomolecular interactions. However, the classic hybrid self-assembly method lacks general applicability toward different self-assembly systems. In this paper, we report a new method based on the reaction kinetics of vinyl sulfone groups presented on surface to control the surface ligand density. Nα,Nα-bis(carboxymethyl)-L-lysine (ab-NTA) was selected as the model biological ligand and the catalyst for surface reaction was screened. The surface reaction was characterized by X-ray photoelectron spectroscopy (XPS) and the surface membrane potential. Static water contact angle was used to quantify the kinetics of the surface reaction, and calculations showed that the rate constant was 0.0012 min-1. The ability of the biological functional surface to bind a histidine labeling protein (SA-6His) was investigated by surface plasmon resonance (SPR). The results show that such a surface has a higher protein binding quantity and binding strength than the traditional NHS-NTA surface. Four biological functional surfaces with different ligand densities were prepared by controlling the reaction time and catalyst, and the protein static adsorption of these surfaces was analyzed by SPR. The results show that ligand density and multivalence of the biological functional surface can be controlled by modulating the reaction time and catalyst.
Control over the ligand surface density provides an accurate molecular basis for the quantitative study of biomolecular interactions. However, the classic hybrid self-assembly method lacks general applicability toward different self-assembly systems. In this paper, we report a new method based on the reaction kinetics of vinyl sulfone groups presented on surface to control the surface ligand density. Nα,Nα-bis(carboxymethyl)-L-lysine (ab-NTA) was selected as the model biological ligand and the catalyst for surface reaction was screened. The surface reaction was characterized by X-ray photoelectron spectroscopy (XPS) and the surface membrane potential. Static water contact angle was used to quantify the kinetics of the surface reaction, and calculations showed that the rate constant was 0.0012 min-1. The ability of the biological functional surface to bind a histidine labeling protein (SA-6His) was investigated by surface plasmon resonance (SPR). The results show that such a surface has a higher protein binding quantity and binding strength than the traditional NHS-NTA surface. Four biological functional surfaces with different ligand densities were prepared by controlling the reaction time and catalyst, and the protein static adsorption of these surfaces was analyzed by SPR. The results show that ligand density and multivalence of the biological functional surface can be controlled by modulating the reaction time and catalyst.
2018, 34(2): 185-193
doi: 10.3866/PKU.WHXB201707175
Abstract:
For a better understanding of the cytotoxicity of polyethyleneimine (PEI), which has long been considered as the "golden standard" for polymeric gene delivery carriers, on the molecular basis, UV-Vis absorption, fluorescence, circular dichroism, dynamic light scattering and zeta-potential measurements were conducted to reveal the interaction between the PEI of average molecular weight 1.8 and 25 kDa (denoted as PEI1.8k and PEI25k, respectively) and human serum albumin (HSA). The effects of interactions on the conformation of HSA and its binding capability to the model compounds, 8-anilino-1-naphthalenesulfonic acid (ANS) and quercetin, were also evaluated. PEI was found to bind to HSA and induce an alteration in the secondary and tertiary structures of the protein and its binding capability toward small compounds. The complex formation with PEI resulted in a more compact and hydrophobic conformation of HSA, accompanying an increase in α-helix content in the case of PEI1.8k and PEI25k at low concentrations. The binding efficacy of ANS and quercetin to HSA was reduced by competitive binding with PEI, however increased by the conformational change of the protein. Higher-molecular-weight PEI was found to interact with HSA more favorably. It was also more efficient in perturbing the conformation and the binding capability of the protein.
For a better understanding of the cytotoxicity of polyethyleneimine (PEI), which has long been considered as the "golden standard" for polymeric gene delivery carriers, on the molecular basis, UV-Vis absorption, fluorescence, circular dichroism, dynamic light scattering and zeta-potential measurements were conducted to reveal the interaction between the PEI of average molecular weight 1.8 and 25 kDa (denoted as PEI1.8k and PEI25k, respectively) and human serum albumin (HSA). The effects of interactions on the conformation of HSA and its binding capability to the model compounds, 8-anilino-1-naphthalenesulfonic acid (ANS) and quercetin, were also evaluated. PEI was found to bind to HSA and induce an alteration in the secondary and tertiary structures of the protein and its binding capability toward small compounds. The complex formation with PEI resulted in a more compact and hydrophobic conformation of HSA, accompanying an increase in α-helix content in the case of PEI1.8k and PEI25k at low concentrations. The binding efficacy of ANS and quercetin to HSA was reduced by competitive binding with PEI, however increased by the conformational change of the protein. Higher-molecular-weight PEI was found to interact with HSA more favorably. It was also more efficient in perturbing the conformation and the binding capability of the protein.
2018, 34(2): 194-200
doi: 10.3866/PKU.WHXB201707262
Abstract:
The amino acid ionic liquid (AAIL) 1-hexyl-3-methylimidazolium threonine salt,[C6mim] [Thr], was prepared by the neutralization method and its structure was confirmed by 1H and 13C NMR spectroscopy. Using benzoic acid as the reference material, the vapor pressure and evaporation enthalpy △glHmθ (Tav) of[C6mim] [Thr] were determined by isothermogravimetric analysis at the average temperature (Tav=438.15 K) and △glHmθ (Tav) was found to be (128.5 ±6.0) kJ·mol-1. Using Verevkin's method, the difference between the heat capacities of the vapor and liquid phases, △glCpmθ, was calculated to be -70.8 J·K-1·mol-1. Subsequently, the enthalpy of vaporization for AAIL[C6mim] [Thr] at different temperatures was determined based on the reference enthalpy of vaporization at 298.15 K, △glHmθ (298.15 K)=138.4 kJ·mol-1. This value is 1.6 kJ·mol-1 higher than that predicted by our theoretical model and less than the experimental error (±3.0 kJ·mol-1) of the isothermogravimetric method. These results show that our theoretical model for determining the evaporation enthalpy of ILs is reasonable. In terms of the Clausius-Clapeyron equation, the hypothetical normal boiling point, Tb, was estimated to be 522.07 K. Thus, the evaporation entropy, △glSmθ (T), and the evaporation Gibbs free energy, △glGmθ (T), of[C6mim] [Thr] could be determined for different temperatures. These results showed that △glGmθ (T) decreases as the temperature increases, the evaporation entropy increases with increaseing temperature. Furthermore, the latter is the driving force in the evaporation process of the AAIL[C6mim] [Thr].
The amino acid ionic liquid (AAIL) 1-hexyl-3-methylimidazolium threonine salt,[C6mim] [Thr], was prepared by the neutralization method and its structure was confirmed by 1H and 13C NMR spectroscopy. Using benzoic acid as the reference material, the vapor pressure and evaporation enthalpy △glHmθ (Tav) of[C6mim] [Thr] were determined by isothermogravimetric analysis at the average temperature (Tav=438.15 K) and △glHmθ (Tav) was found to be (128.5 ±6.0) kJ·mol-1. Using Verevkin's method, the difference between the heat capacities of the vapor and liquid phases, △glCpmθ, was calculated to be -70.8 J·K-1·mol-1. Subsequently, the enthalpy of vaporization for AAIL[C6mim] [Thr] at different temperatures was determined based on the reference enthalpy of vaporization at 298.15 K, △glHmθ (298.15 K)=138.4 kJ·mol-1. This value is 1.6 kJ·mol-1 higher than that predicted by our theoretical model and less than the experimental error (±3.0 kJ·mol-1) of the isothermogravimetric method. These results show that our theoretical model for determining the evaporation enthalpy of ILs is reasonable. In terms of the Clausius-Clapeyron equation, the hypothetical normal boiling point, Tb, was estimated to be 522.07 K. Thus, the evaporation entropy, △glSmθ (T), and the evaporation Gibbs free energy, △glGmθ (T), of[C6mim] [Thr] could be determined for different temperatures. These results showed that △glGmθ (T) decreases as the temperature increases, the evaporation entropy increases with increaseing temperature. Furthermore, the latter is the driving force in the evaporation process of the AAIL[C6mim] [Thr].
2018, 34(2): 201-207
doi: 10.3866/PKU.WHXB201707131
Abstract:
Density functional theory-based calculations have been carried out to study the bonding and reactivity in RB-AsR (R=H, F, OH, CH3, CMe3, CF3, SiF3, BO) systems. Our calculations demonstrated that all the studied systems adopted bent geometry (∠R-B-As ≈ 180° and ∠B-As-R ≈ 90° or less). The reason for this bending was explained with the help of a valence-orbital model. The potential energy surfaces for three possible isomers of RB-AsR systems were also generated, indicating that the RB-AsR isomer was more stable than R2B-AsR when R=SiF3, CMe3, and H. The B-As bond character was analyzed using natural bond orbital (NBO) and Wiberg bond index (WBI) calculations. The WBI values for B-As bonds in F3SiB-AsSiF3 and HB-AsH were 2.254 and 2.209, respectively, indicating that this bond has some triple-bond character in these systems. While the B centers prefer nucleophilic attack, the As centers prefer electrophilic attack.
Density functional theory-based calculations have been carried out to study the bonding and reactivity in RB-AsR (R=H, F, OH, CH3, CMe3, CF3, SiF3, BO) systems. Our calculations demonstrated that all the studied systems adopted bent geometry (∠R-B-As ≈ 180° and ∠B-As-R ≈ 90° or less). The reason for this bending was explained with the help of a valence-orbital model. The potential energy surfaces for three possible isomers of RB-AsR systems were also generated, indicating that the RB-AsR isomer was more stable than R2B-AsR when R=SiF3, CMe3, and H. The B-As bond character was analyzed using natural bond orbital (NBO) and Wiberg bond index (WBI) calculations. The WBI values for B-As bonds in F3SiB-AsSiF3 and HB-AsH were 2.254 and 2.209, respectively, indicating that this bond has some triple-bond character in these systems. While the B centers prefer nucleophilic attack, the As centers prefer electrophilic attack.
2018, 34(2): 208-212
doi: 10.3866/PKU.WHXB201707031
Abstract:
The evolution of cesium iodide band gap as a function of pressure is studied in the range from 0 to 60 GPa. Within this range, two structural phase transitions occurred, and the band gap was affected by the compression pressure and structural rearrangement. The band gap estimation under pressure, as obtained by the density functional theory methods, successfully reproduced the experimental trend of the optical gap and electrical resistivity, namely, a general decreasing tendency, an early maximum, and a discontinuous peak around 40 GPa.
The evolution of cesium iodide band gap as a function of pressure is studied in the range from 0 to 60 GPa. Within this range, two structural phase transitions occurred, and the band gap was affected by the compression pressure and structural rearrangement. The band gap estimation under pressure, as obtained by the density functional theory methods, successfully reproduced the experimental trend of the optical gap and electrical resistivity, namely, a general decreasing tendency, an early maximum, and a discontinuous peak around 40 GPa.
2018, 34(2): 213-218
doi: 10.3866/PKU.WHXB201707172
Abstract:
A solid polymer electrolyte (SPE), composed of sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) and poly(ethylene oxide) (PEO), is prepared by a simple solution-casting method. The physicochemical and electrochemical properties of the NaTFSI/PEO ([EO]/[Na+]=15) SPE in terms of its phase transitions, crystallization, thermal stability, ionic conductivity, and anodic electrochemical stability are systematically investigated. We demonstrate that the NaTFSI/PEO SPE has a relatively high ionic conductivity (σ ≈ 10-3 S·cm-1) at 80℃, excellent electrochemical stability (4.86 V vs. Na+/Na), and thermal stability up to 350℃. More importantly, the NaTFSI-based SPE delivers not only excellent chemical and electrochemical stability with sodium metal, but also good cycling and rate performances in an Na|SPE|NaCu1/9Ni2/9Fe1/3Mn1/3O2 cell.
A solid polymer electrolyte (SPE), composed of sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) and poly(ethylene oxide) (PEO), is prepared by a simple solution-casting method. The physicochemical and electrochemical properties of the NaTFSI/PEO ([EO]/[Na+]=15) SPE in terms of its phase transitions, crystallization, thermal stability, ionic conductivity, and anodic electrochemical stability are systematically investigated. We demonstrate that the NaTFSI/PEO SPE has a relatively high ionic conductivity (σ ≈ 10-3 S·cm-1) at 80℃, excellent electrochemical stability (4.86 V vs. Na+/Na), and thermal stability up to 350℃. More importantly, the NaTFSI-based SPE delivers not only excellent chemical and electrochemical stability with sodium metal, but also good cycling and rate performances in an Na|SPE|NaCu1/9Ni2/9Fe1/3Mn1/3O2 cell.
2018, 34(2): 219-226
doi: 10.3866/PKU.WHXB201707173
Abstract:
Sodium ion batteries (SIBs), a promising substitute for lithium ion batteries (LIBs), have attracted extensive attention due to the abundance and low cost of sodium resources. In addition, flexible sodium-ion batteries may be able to satisfy the demands of large-scale energy storage applications for portable, wearable, and flexible electronics. Compared to the development of cathode materials, the progress on anode materials has been relatively slow. Therefore, the exploration of low-cost anode materials with high Na+ storage capacity is very important. Herein, we present oxygen-deficient Na2Ti3O7 nanobelts grown on carbon cloth (CC) as a promising novel flexible anode material for SIBs. Free-standing Na2Ti3O7 nanobelts with oxygen vacancies were directly grown on CC through a simple hydrothermal and thermal reduction process. Benefiting from the improved conductivity and increased active sites after the introduction of oxygen vacancies, the new material exhibits a high reversible capacity of 100 mAh·cm-2 at 200 mA·cm-2, with almost 80% capacitance retention after 200 cycles. When the current density was increased to 400 mA·cm-2, a high capacity of 69.7 mAh·cm-2 was achieved, which is three times that of bare Na2Ti3O7 nanobelts on CC. This 3D oxygen-deficient electrode can significantly promote the transport of Na+ ions and electrons, leading to remarkably improved electrochemical properties. Furthermore, this work constitutes a promising strategy to rationally design and fabricate novel Na2Ti3O7-based anodes with enhanced capacitive behavior, which hold great promise for energy storage/conversion devices, facilitating the large-scale implementation of high-performance flexible SIBs.
Sodium ion batteries (SIBs), a promising substitute for lithium ion batteries (LIBs), have attracted extensive attention due to the abundance and low cost of sodium resources. In addition, flexible sodium-ion batteries may be able to satisfy the demands of large-scale energy storage applications for portable, wearable, and flexible electronics. Compared to the development of cathode materials, the progress on anode materials has been relatively slow. Therefore, the exploration of low-cost anode materials with high Na+ storage capacity is very important. Herein, we present oxygen-deficient Na2Ti3O7 nanobelts grown on carbon cloth (CC) as a promising novel flexible anode material for SIBs. Free-standing Na2Ti3O7 nanobelts with oxygen vacancies were directly grown on CC through a simple hydrothermal and thermal reduction process. Benefiting from the improved conductivity and increased active sites after the introduction of oxygen vacancies, the new material exhibits a high reversible capacity of 100 mAh·cm-2 at 200 mA·cm-2, with almost 80% capacitance retention after 200 cycles. When the current density was increased to 400 mA·cm-2, a high capacity of 69.7 mAh·cm-2 was achieved, which is three times that of bare Na2Ti3O7 nanobelts on CC. This 3D oxygen-deficient electrode can significantly promote the transport of Na+ ions and electrons, leading to remarkably improved electrochemical properties. Furthermore, this work constitutes a promising strategy to rationally design and fabricate novel Na2Ti3O7-based anodes with enhanced capacitive behavior, which hold great promise for energy storage/conversion devices, facilitating the large-scale implementation of high-performance flexible SIBs.
