Amorphous Silicon Based Biosensor for Food Quality Assessment: Feasibility Study on Milk’s Fat Content

This paper presents a study on a Lab-on-Chip system based on the optical interaction between biological material and optical devices for the detection of analyte’s properties inside a solution or mixture. The reported LoC performs both interaction and detection phase in the same chip, taking advantage of a polymer waveguiding structure optically coupled with a thin-film amorphous silicon photodiode fabricated on a single glass substrate. Before its actual implementation in biomolecular recognition applications, we report a feasibility study on the detection of fat content in milk, carried out by interpolating simulated data with the measured electro-optical response of the sensor. The sensing demonstration highlights a limit of detection of 106 ppm and a sensitivity of about 8.7 pA/(g/dL), encouraging further developments and an actual implementation in food quality control.