Detection of Human Ig G Using Photoluminescent Porous Silicon Interferometer.

Photoluminescent porous silicon (PSi) interferometers having dual optical properties, both Fabry-Pérot fringe and photolumincence (PL), have been developed and used as biosensors for detection of Human Immunoglobin G (Ig G). PSi samples were prepared by electrochemical etching of p-type silicon under white light exposure. The surface of PSi was characterized using a cold field emission scanning electron microscope. The sensor system studied consisted of a single layer of porous silicon modified with Protein A. The system was probed with various fragments of aqueous human immunoglobin G (Ig G) analyte. Both reflectivity and PL were simultaneously measured under the exposure of human Ig G. An increase of optical thickness and decrease of PL were obtained under the exposure of human Ig G. Detection limit of 500 fM was observed for the human Ig G.