Detecting Penicillin in Milk with a Wireless Magnetoelastic Biosensor

摘要

A wireless magnetoelastic biosensor for the direct detection of penicillin G in milk has been developed. The sensor was fabricated by applying a magnetoelastic ribbon with a layer of pH-sensitive polymer and upon it a sensing film containing bovine serum albumin (BSA) and penicillinase. The penicillinase-catalyzed hydrolysis of penicillin G decreases the solution pH, resulting in the polymer shrinking and consequently the resonance frequency of the magnetoelastic sensor increasing. Under optimum operating conditions the system provides a wide linear response between 1.9 mM and 5.0 mM with a very low detection limit of 1.3 mM. The immobilized penicillinase on magnetoelastic ribbon was very stable and provided good reproducible signal after regeneration up to 30 times with a relative standard deviation (R.S.D.) lower than 9%. Good recoveries and precisions were obtained when spiked raw milk samples were analyzed.