基于光纤式动态光散射的人血清白蛋白研究

A Study on Human Serum Albumin Gene Based On Fiber Dynamic Light Scattering

人体尿液中血清白蛋白急剧增加会导致肾脏病发生几率增大,利用动态光散射技术(dynamic light scattering,DLS)研究人血清白蛋白有助于推动诊断肾脏病的早期发现。分析了人血清白蛋白的物理模型;利用单模光纤搭建了动态光散射实验系统,并配制了实验所需的人血清白蛋白水溶液;最后使用该系统研究了人血清白蛋白分子的扩散系数在不同蛋白浓度和pH值条件下的扩散系数。实验和分析结果表明库仑力对蛋白质的扩散起主要作用,在等电位点下(pH=5.2)库仑力的影响消失,蛋白质的扩散系数最小;在等电位点测量出扩散系数随浓度的增加而线性减小;在浓度5 mg/mL～40 mg/mL内互扩散系数Dm=D0[1-(0.00194±0.00008)],D0=(6.74±0.01)×10-7cm2/s为外推至零浓度下23℃时蛋白质的扩散系数。这里C为蛋白质浓度,实验测得人血清白蛋白的半径为(3.44±0.01)nm。

The quick augment of serum albumin gene in human urine may induce renal diseases. The study on human serum albumin by dynamic light scattering technique is helpful to the discovery of inchoate renal diseases. In this paper, the physical model of human serum albumin gene is analyzed firstly. And then the dynamic light scattering experiment setup based on single-mode fibers is constructed, and the water solutions of human serum albumin required in experiments are prepared. The diffusion coefficient of human serum album was measured at different concentrations and pH by means of the above-mentioned setup. Experimental and analytic results indicate that coulomb interactions between the charged proteins acted as main contribution to the diffusion coefficient; the effect of coulomb vanished at the isoelectric （5.2） , and the diffusion coefficient of protein is close to minimal. At the isoelectric, the diffusion coefficient decreased linearly with concentration increase. In the concentration range of 5 mg/mL - 40 mg/mL, when 532 nm light was used, it was found that Dm = Do [ 1-（0. 00194 ± 0. 00008 ） ] , where Do = （ 6.74 ± 0.01 ） × 10^-7 cm^2/s extrapolated to zero concentration at 23 ℃ and C is in units of mg/mL. The measured diameter of human serum albumin is （3.44 ± 0.01 ）nm.