Spectroscopic analysis on the binding interaction of biologically active pyrimidine derivative with bovine serum albumin

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.

CdS nanocrystals as fluorescent probe for detection of dolasetron mesylate in aqueous solution:Application to biomedical analysis

A simple and straightforward method for the determination of dolasetron mesylate(DM) in aqueous solution was developed based on the fluorescence quenching of 3-Mercaptopropionic acid(MPA) capped Cd S quantum dots(QDs).The structure,morphology,and optical properties of synthesized QDs were characterized by using UV-Vis absorption spectroscopy,fluorescence spectroscopy,transmission electron microscopy(TEM) and dynamic light scattering(DLS) measurements.Under the optimum conditions,the MPA-Cd S QDs fluorescence probe offered good sensitivity and selectivity for detecting DM.The probe provided a highly specific selectivity and a linear detection of DM in the range of 2–40 μg/m L with detection limit(LOD) 1.512 μg/m L.The common excipients did not interfere in the proposed method.The fluorescence quenching mechanism of Cd S QDs is also discussed.The developed sensor was applied to the quantification of DM in urine and human serum sample with satisfactory results.

Fluorimetric study of the interaction between ATP and ciprofloxacin-Y^(3+) complex and its application

A simple spectrofluorimetric method was developed for determination of trace amount of adenosine disodium triphosphate(ATP).Under the optimum conditions,we studied the interaction between CIP-Y3+-ATP complex by using absorption and fluorescence spectra.It was observed that ATP remarkably enhanced the fluorescence intensity of the CIP-Y3+ complex at λem=415 nm and the enhanced fluorescence intensity of Y3+ ion remained proportional to the concentration of ATP.The developed method was successfully applied for...