Preparation of Porous Silicon Substrate for Protein Microarray Fabrication by Double-Cell Electrochemical Etching Method

Uniformly porous silicon substrate with large surface area (12 mm × 58 mm) was prepared by double-cell electrochemical etching method. After functionalized with epoxide groups, the porous silicon substrate can be employed to fabricate protein microarray. In proof of principle experiment, well-known biomolecule recognition system (the interaction of mouse IgG with rabbit anti-mouse IgG antibody) was chosen to establish the new microarray format. It was found that the detection sensitivity of the mouse IgG microarray was dependent on preparing conditions of porous silicon substrate including etching current density, etching time, and concentration of HF. Under the optimal conditions (500 mA cm−2 etching current density, 450 s etching time and 25% HF), specific binding could be detected using rabbit anti-mouse IgG antibody at concentrations as low as 10 ng mL−1 with a dynamic range from 316 ng mL−1 to 10 μg mL−1. The results demonstrate that the as-prepared porous silicon substrate could be used to fabricate the protein microarray with high reaction capability.