Detection of Salmonella enterica on silicon substrates biofunctionalized with anti-Salmonella IgG, analyzed by FTIR spectroscopy

Foodborne diseases are considered a health problem, Salmonella is part of the main microorganisms that generate this type of diseases, so its detection requires a short period of time, biosensors can be a good option to meet this need. In this work, three substrates (crystalline and amorphous silicon, hydrogenated amorphous silicon carbide) were biofunctionalized applying self-assembled monolayers technique, presence of characteristic functional groups of the assembly was verified by Fourier transform infrared spectroscopy (FTIR). Anti-Salmonella IgG antibodies against whole bacteria were generated. Second derivative of each FTIR detection spectrum was obtained, having modifications in the zone between 1600-1700 cm^-1 given by the secondary structure of proteins, being crystalline silicon and hydrogenated amorphous silicon carbide platforms, which presented the most notorious bands. Detection was performed on flat substrates with a specific area (25 mm²), a detection time of 60 min was stablished and a concentration of 500 CFU/mL was detected. With this, the three silicon and derivatives biofunctionalized may have future applications in food microbial quality monitoring.

Keywords: biosensor, silicon, FTIR, Salmonella, IgG.