Abstract:

Porous silicon has attracted considerable attention for sensor application due to its remarkable optical properties and the easy fabrication. In this study, an optical immunoassay was developed by the optic reflectance spectroscopy of the porous silicon Bragg reflectors. The artificial immunogen of hydroxysafflor yellow A(HSYA-BSA) and the polyclonal anti-HSYA antibodies were employed as the target and probe, respectively. HSYA is the main chemical component of the flower of the safflower, which is widely used in traditional Chinese medicine for treatment of cerebrovascular and cardiovascular diseases. First, porous silicon Bragg reflector was functionalized using oxidation and silanization. Then, the polyclonal anti-HSYA antibodies were immobilized to the porous silicon Bragg reflector surface used a crosslink method. After the antigen-antibody reaction, the reflection spectrum red shifts and the red shift of spectrum increases with the increase of HSYA-BSA concentration. It is showing the red shifts of the reflectance spectrum as function of HSYA-BSA concentrations. Control experiments were also presented with negative serum and the result suggests that the reflection spectrum red shift is due to selective antigen-antibody binding and this porous silicon Bragg reflector immunosensor possess high specificity. Compared to conventional ELISA, the procedures are label-free and detection time is reduced. Thus, this research lays a foundation of exploiting label-free porous silicon Bragg reflector immunosensor and could be further developed for component detection of safflower of a quick and accurate determination.

Key words: Porous silicon Bragg reflector; Optical detection; Hydroxysafflor yellow A; Reflectances pectrum