SEPARATION AND OPTICAL PROFILING OF PROTEINS USING POROUS SI NANOSTRACTURES

Protein fractionation, separation and profiling are extremely important in all areas of biology and medical research. Despite the progress in protein analysis technologies, currently used methods still rely on polyacrylamide gel electrophoresis processes, which are laborious, lengthy, multistep, and require dyes or other labels. Herein, we report on new label-free and reagentless analytical method for protein profiling by employing a nanostructured porous silicon matrix.

Porous silicon (PSi) chips displaying a smooth gradient of the pore size, in the range of 10 – 100 nm, are fabricated by electrochemical etching of silicon wafers. The resulting nanostructure is thermally oxidized and assembled with polydimethylsiloxane (PDMS) micro-channels via plasma activation to allow processing of small sample volumes. Optical detection based on Reflective Interferometric Fourier Transform Spectroscopy (RIFTS) is used to monitor in real-time the fractionation and separation of model proteins. We demonstrate the ability of the system to separate biomolecules based on their size while allowing qualitative and quantitative optical monitoring of the process in a label-free format.