光谱法研究纳米二氧化硅(SiO_2)催化超声波照射对牛血清白蛋白(BSA)的损伤

利用紫外-可见(Uv-Vis)光谱和荧光光谱研究了超声波照射激活纳米二氧化硅(SiO2)粒子对牛血清白蛋白(BSA)分子的损伤,并考查了超声波照射时间、纳米SiO2粉末加入量、溶液酸度和超声波照射功率等因素对BSA分子损伤程度的影响.结果表明,对于体系温度为(37.0±0.2)℃和浓度为1.0×10-5mol·-1的BSA溶液,UV-Vis光谱显示,随着超声波照射时间,纳米SiO2粉末加入量,溶液pH值和照射功率的增大呈现出越来越明显的增色效应.然而,BSA溶液的荧光光谱却随着上述因素的增大呈现出越来越明显的猝灭现象.此外,还初步探讨了超声波照射激活纳米siO2粒子对BSA分子损伤的机理,认为是声致发光或高热激发使纳米siO2粒子产生·OH自由基,进而损伤溶液中的BSA分子.这一研究结果对声催化方法应用于临床治疗肿瘤以及纳米药物的开发具有一定的指导意义.

Investigation on Damage of Bovine Serum Albumin (BSA) Catalyzed by Nano-Sized Silicon Dioxide (SiO_2) under Ultrasonic Irradiation Using Spectral Methods

The damage of bovine serum albumin (BSA) molecules under ultrasonic irradiation in the presence of nano-sized silicon dioxide (SiO2) particles was studied by UV-Vis and fluorescence spectra. In addition, the influences of ultrasonic irradiation time, nano-sized SiO2 addition amount, solution acidity (pH) and ultrasonic irradiation power on the damage of BSA molecules in aqueous solution were also detected. For BSA solution of 1.0 10-5 mol·L-1 at (37.0±0.2) ℃, the UV-Vis spectra of BSA solutions showed that the absorption peaks of BSA displayed obvious hyperchromic effect with the increase in some influence factors such as ultrasonic irradiation time, nano-sized SiO2 addition amount, pH value and ultrasonic irradiation power. However, the fluorescence spectra of BSA solutions showed the phenomenon of fluorescence quenching with the increase in ultrasonic irradiation time, nano-sized SiO2 addition amount, pH value and ultrasonic irradiation power. Moreover, the possible mechanism behind the damage of BSA molecule in the presence of nano-sized SiO2 powders under ultrasonic irradiation was discussed. It was considered that the damage of BSA molecules was attributed to the formation of ·OH radicals resulting from the sonoluminescence and high-heat excitation of ultrasonic cavitation. The research results could be of great significance to using sonocatalytic method to treat tumour in clinic application and for developing nano-sized drug in the future.