Encapsulation of Gold Nanoparticles into Functionalized Silica Nanoparticles Stabilized on Triacetyl Cellulose for Gluten Determination

A sensitive, rapid, and portable optical sensor for the determination of gluten is fabricated. The sensing probe is composed of gold nanoparticles encapsulated into hyper branched polycitric acid modified silica nanoparticles Si-g-PCA/AuNPs. Portability is imposed by stabilizing the as-prepared sensing probe on the triacetyl cellulose membrane as a solid substrate. The sensing probe’s synthesis and immobilization were thoroughly investigated by using spectroscopy and microscopy techniques including FT-IR, UV-vis, SEM, EDX, AFM, and BET analysis. The as-prepared sensor showed an increment at 530 nm in the presence of various concentrations of gluten. Effective parameters, including pH and response time on the sensor response, are precisely optimized, and a linear range from 49.50 to 370.37 µgmL-1 is obtained for gluten determination. The present sensor was successfully applied for gluten detection into gluten-free bread as a real sample. Moreover, the sensor showed multi-usage capability in which sensing characteristics could be recovered in the presence of 55% ethanol.