水溶性芴与噻吩共聚物的合成及蛋白质对其荧光猝灭的影响

采用Suzuki偶合方法合成了含羧酸基团的新型阴离子型水溶性绿光的9,9’-二丙酸钠芴(DPF)和噻吩(TH)共聚物,聚合物分子量约为9000左右,具有较好的水溶性(5 mg/mL).研究了共聚物在不同pH水溶液中的荧光性质,结果表明当pH ＜4时,羧基以COOH形式存在,造成共聚物溶解度降低并产生聚集,荧光减弱;当p...

SYNTHESIS AND CHARACTERIZATION OF A WATER-SOLUBLE POLY(FLUORENE-co-THIOPHENE)AND ITS FLUORESCENCE QUENCHING BY PROTEINS

An anionic water-soluble polymer was synthesized by Suzuki-coupling between 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9,9-bis(3-(tert-butyl propanoate))]fluorene,2,7-dibromo-9,9-bis(3′-(tert-butylpropanoate))fluorene,and 2,5-dibromothiophene,which was followed by treatment in trifluoroacetic acid and aqueous Na2CO3 to afford the functional carboxylic acid groups,with number-averaged molecular weight about 9000 and polydispersity of 1.37.The polymer emits green fluorescence with a main peak at around 446 nm and a shoulder at about 464 nm.The absorption and fluorescence spectra of the polymer are strongly dependent on pH value owing to the partial protonation of carboxylate groups and the aggregation of the polymer chains.The change in polymer fluorescence upon interaction with different proteins in phosphate buffer solution(PBS) was also studied.The difference between the proteins is that bovine serum albumin(BSA) is negatively charged,histone is positively charged and hemoglobin is neutral.Strong fluorescence quenching of the polymer was observed in the presence of histone,the lowest quenching concentration was observed to be 5×10-8 mol/L.Under similar experimental conditions,whereas weak quenching was observed in the other proteins hemoglobin and BSA.The variation in the fluorescence of the polymer in the presence of different proteins is due to the different electrostatic interactions between the polymer and the proteins.