Preparation of a biochip on porous silicon and application for label-free detection of small molecule-protein interactions

A new approach for the preparation of a biochip on porous silicon and the application of the biochip for detection of small molecule-protein interactions with desorption/ionization on porous silicon (DIOS) was demonstrated. The galvanostatically etched porous silicon substrates were chemically modified firstly to yield carboxylic acid terminated surfaces, and then the protein was covalently attached to the surface through amide bonding. By applying a solution of candidate chemicals to the surface and a subsequent wash step, the masses of captured compounds could be analyzed by DIOS. DIOS has advantages of being a direct detection tool compared to the classic fluorescence or chemiluminescence methods, because the process of labeling molecules employed in the fluorescence or chemiluminescence methods can sometimes alert the properties of the labeled molecule. The recognition between proteins and their binding partners is efficient and selective. A good tolerance to disturbance and high enrichment factor of the biochip to the analytes was observed. As an on-chip-based approach, the demonstrated method has a potential to perform in a high-throughput format.