基于表面等离子体子共振的白蛋白免疫传感器的研究

采用自行组装的全波长表面等离子体子共振(SPR)传感装置,以对金和蛋白抗体均有较强吸附作用的A蛋白作为基底膜,测试了A蛋白在金膜表面结合的动力学常数,其结果为2.3×10⁵L/(mol·s).研究了在A蛋白基底膜上白蛋白抗体的定向自组装程度和速率.观测了白蛋白抗体与抗原之间免疫反应的动力学过程,并优化了实验条件.结果表明,白蛋白抗原的浓度在0.02～10mg/mL范围内与信号的响应值呈良好的线性关系.将此SPR传感器用于糖尿病肾病患者尿蛋白的检测,结果较好.

Studies on an Immunosensor of Albumin Based on Surface Plasmon Resonance

A practical and simple immunosensor based on surface plasmon resonance(SPR) technique has been developed to determine the albumin antigen. The SPRdevice was different from popular SPR instrument that modulated angle of incident light at fixed excitation wavelength. The device used in the experimental process is designed on the basis of fixing the angle of incident light and measuring the change of resonant wavelength. The protein A was chosen as the substrate membrane because it can not only form a stable complex with gold, but also form complex with ordinary antibodies. The process of combination between gold and protein Awas monitored, and the kinetic adsoption constant is 23×10⁵L·mol^-1·s^-1. The other combination processed, such as protein Aand albumin antibody, and albumin antibody and antigen had also been studied in real time through observing the change of resonant wavelengths in SPR spectra. The kinetic adsoption constants of all process had been obtained. Using the citrate buffer to rinse the sensing surface, the complex of antibody and antigen could be rinsed out from protein A, and protein Acould be recovered. The relationship between concentrations of albumin antigen and changes of resonant wavelength is linear in the range of 0.02-10 mg/mL. The amounts of albumin antigen in the urine of diabetics have been determined with the SPR sensor. The results are in good agreement with those obtained with standard method.