In this work, an enzymatic sensor, based on a bionanocomposite film consisting of a polyelectrolyte complex (PEC) (Chitosan/kappa-carrageenan) doped with gold nanoparticles (AuNPs) encapsulating glucose oxidase (GOD) deposited on a gold electrode (Au) for glucose sensing, is described. Using the electrocatalytic synergy of AuNPs and GOD as a model of enzyme, the variation of the current (µA) as a function of the log of the glucose concentration (log [glucose]), shows three times higher sensitivity for the modified electrode (283.9) compared to that of the PEC/GOD modified electrode (93.7), with a detection limit of about 5 µM and a linearity range between 10 µM and 7 mM. The response of the PEC/AuNPs/GOD based biosensor also presents good reproducibility, stability, and negligible interfering effects from ascorbic acid, uric acid, urea, and creatinine. The applicability of the PEC/AuNPs/GOD based biosensor was tested in glucose-spiked saliva samples and acceptable recovery rates were obtained.
Keywords: bionanocomposite; chitosan; glucose oxidase; gold nanoparticles encapsulation; kappa-carrageenan; polyelectrolyte complex.