A biologically active antibacterial reagent, 2-amino-6-hydroxy-4-（4-N, N-dimethylaminophenyl）-pyr- imidine-5-carbonitrile （AHDMAPPC）, was synthesized. It was employed to investigate the binding in- teraction with ...A biologically active antibacterial reagent, 2-amino-6-hydroxy-4-（4-N, N-dimethylaminophenyl）-pyr- imidine-5-carbonitrile （AHDMAPPC）, was synthesized. It was employed to investigate the binding in- teraction with the bovine serum albumin （BSA） in detail using different spectroscopic methods. It ex- hibited antibacterial activity against Escherichia cali and Staphylococcus aureus which are common food poisoning bacteria. The experimental results showed that the fluorescence quenching of model carrier protein BSA by AHDMAPPC was due to static quenching. The site binding constants and number of binding sites （n ≈ 1） were determined at three different temperatures based on fluorescence quenching results. The thermodynamic parameters, enthalpy change （AH）, free energy （AG） and entropy change （AS） for the reaction were calculated to be 15.15 kJ/mol, -36.11 kJ/mol and 51.26J/mol K according to van＇t Hoff equation, respectively. The results indicated that the reaction was an endothermic and spontaneous process, and hydrophobic interactions played a major role in the binding between drug and BSA. The distance between donor and acceptor is 2.79 nm according to Forster＇s theory. The alterations of the BSA secondary structure in the presence of AHDMAPPC were confirmed by UV-visible, synchronous fluorescence, circular dichroism （CD） and three-dimensional fluorescence spectra. All these results in- dicated that AHDMAPPC can bind to BSA and be effectively transported and eliminated in the body. It can be a useful guideline for further drug design.展开更多
在有机相中合成了不同尺寸的CdS和CdSe量子点,并利用Langmuir-Blodgett(LB)技术将相同尺寸的CdS和CdSe量子点组装成多层复合纳米有序结构.采用荧光光谱研究了CdS和CdSe量子点在混合体系和多层复合纳米有序结构状态下的荧光共振能量转移(...在有机相中合成了不同尺寸的CdS和CdSe量子点,并利用Langmuir-Blodgett(LB)技术将相同尺寸的CdS和CdSe量子点组装成多层复合纳米有序结构.采用荧光光谱研究了CdS和CdSe量子点在混合体系和多层复合纳米有序结构状态下的荧光共振能量转移(Fluorescence resonance energy transfer,FRET).我们观察到CdS和CdSe量子点混合溶液与当溶剂挥发形成固态膜中,CdS量子点的荧光强度较溶液状态下强烈猝灭,表明当颗粒间距离减小时CdS和CdSe量子点间产生较高效率的荧光共振能量转移.在多层复合纳米有序结构中,随着给体CdS量子点层数的增加,单层受体CdSe量子点的荧光逐步增强,这表明层间纵向能量转移率随给体层数的增加而提高.展开更多
Quantum dots (QDs) have the potential to be used in the multiplexed bioanalysis for their unique property:multi-color QDs can be excited at the same single wavelength light. In this work,high quan-tum yield multi-colo...Quantum dots (QDs) have the potential to be used in the multiplexed bioanalysis for their unique property:multi-color QDs can be excited at the same single wavelength light. In this work,high quan-tum yield multi-color core/shell QDs were prepared. After being water-solubilized by amphiphilic polymer based on self-assembling,the QDs would be labeled by two different IgGs and used in the multiplexed biodetection. Fluorescence resonance energy transfer (FRET) should be avoided in the multiplexed biodetection. In this work,spectral analysis showed that no FRET appeared in water-soluble QDs modified by amphiphilic polymer. The immunofluorescence in vitro indicated that the QDs-IgGs bioconjugates had excellent species-specific detection ability with nearly non-specific binding. The setting of this model will help to support the application of multi-color QDs in the multiplexed bioanalysis communities.展开更多
基金receiving a fellowship from UGCNew Delhi[University Grant Commission,the XIth plan(Faculty Improvement Programme)]DST and UGC for providing funds to the department under FIST and SAP programme
文摘A biologically active antibacterial reagent, 2-amino-6-hydroxy-4-（4-N, N-dimethylaminophenyl）-pyr- imidine-5-carbonitrile （AHDMAPPC）, was synthesized. It was employed to investigate the binding in- teraction with the bovine serum albumin （BSA） in detail using different spectroscopic methods. It ex- hibited antibacterial activity against Escherichia cali and Staphylococcus aureus which are common food poisoning bacteria. The experimental results showed that the fluorescence quenching of model carrier protein BSA by AHDMAPPC was due to static quenching. The site binding constants and number of binding sites （n ≈ 1） were determined at three different temperatures based on fluorescence quenching results. The thermodynamic parameters, enthalpy change （AH）, free energy （AG） and entropy change （AS） for the reaction were calculated to be 15.15 kJ/mol, -36.11 kJ/mol and 51.26J/mol K according to van＇t Hoff equation, respectively. The results indicated that the reaction was an endothermic and spontaneous process, and hydrophobic interactions played a major role in the binding between drug and BSA. The distance between donor and acceptor is 2.79 nm according to Forster＇s theory. The alterations of the BSA secondary structure in the presence of AHDMAPPC were confirmed by UV-visible, synchronous fluorescence, circular dichroism （CD） and three-dimensional fluorescence spectra. All these results in- dicated that AHDMAPPC can bind to BSA and be effectively transported and eliminated in the body. It can be a useful guideline for further drug design.
文摘在有机相中合成了不同尺寸的CdS和CdSe量子点,并利用Langmuir-Blodgett(LB)技术将相同尺寸的CdS和CdSe量子点组装成多层复合纳米有序结构.采用荧光光谱研究了CdS和CdSe量子点在混合体系和多层复合纳米有序结构状态下的荧光共振能量转移(Fluorescence resonance energy transfer,FRET).我们观察到CdS和CdSe量子点混合溶液与当溶剂挥发形成固态膜中,CdS量子点的荧光强度较溶液状态下强烈猝灭,表明当颗粒间距离减小时CdS和CdSe量子点间产生较高效率的荧光共振能量转移.在多层复合纳米有序结构中,随着给体CdS量子点层数的增加,单层受体CdSe量子点的荧光逐步增强,这表明层间纵向能量转移率随给体层数的增加而提高.
基金the National Science and Technology Program for Key Projects (Grant No.2004BA519A56-04)the 863 Program (Grant No.2007AA021808)
文摘Quantum dots (QDs) have the potential to be used in the multiplexed bioanalysis for their unique property:multi-color QDs can be excited at the same single wavelength light. In this work,high quan-tum yield multi-color core/shell QDs were prepared. After being water-solubilized by amphiphilic polymer based on self-assembling,the QDs would be labeled by two different IgGs and used in the multiplexed biodetection. Fluorescence resonance energy transfer (FRET) should be avoided in the multiplexed biodetection. In this work,spectral analysis showed that no FRET appeared in water-soluble QDs modified by amphiphilic polymer. The immunofluorescence in vitro indicated that the QDs-IgGs bioconjugates had excellent species-specific detection ability with nearly non-specific binding. The setting of this model will help to support the application of multi-color QDs in the multiplexed bioanalysis communities.
