Hybrid bio/non-bio interfaces for protein-glucose interaction monitoring

Amphiphilic proteins, which self-assemble at solid-liquid interface in nanometric biolayer, such as hydrophobins, can be used as multifunctional film to passivate porous silicon dioxide and also sense glucose. Several porous silicon dioxide optical transducers (rugate filter, Thue-Morse sequence, and microcavity) have been protein-modified and tested in monitoring hydrophobins-glucose binding. A simple, easy-to-integrate technique, such as water contact angle, is able to reveal sugar presence at 1.2 mg/ml, whereas spectroscopic reflectometry fails. Fluorescence measurements confirm protein layer-glucose interaction. This proof-of-concept measurement could be the starting point for small analytes porous silicon based optical sensors.