Aptamer- and Fab’- functionalized microring resonators for Aflatoxin M1 detection

Silicon oxynitride (SiON) microring resonators areused to develop a biosensor device to detect Aflatoxin M1 (AFM1),a carcinogenic mycotoxin present in milk. Two different surfacefunctionalization strategies are tested to realize an affinity biosens-ing device. Both strategies are based on the formation of a silanesurface layer able to bind either specific DNA-aptamers or anti-gen binding fragments (Fab’). The sensing device consists of anarray of four SiON microring resonators, fiber-coupled to a verti-cal cavity surface emitting laser operating at 850 nm. Detection isrealized with off-chip silicon photodetectors. With both function-alizations, we demonstrate a specific detection of AFM1 in buffer,while the nonspecific detection of Ochratoxin is not occurring. Re-peatability and reproducibility of both functionalization strategiesare discussed.