Preparation and characterization of enzymes-modified surfaces for their use in bioelectrochemical measurement systems

A novel immobilization material for enzyme immobilization based on cetyltrimethylammonium bromide modified dellit (CTAB-Del) was successfully synthesized and utilized in the preparation of pyranose oxidase (PyOx) biosensors (CTAB-Del/PyOx).The intercalation of CTAB into Del was confirmed by FT-IR, XRD and TGA techniques. PyOx was immobilized onto the glassy carbon electrode using CTAB-Del as a support via glutaraldehyde crosslinking. Porous structures of clays are important for the diffusion of glucose and oxygen as a co-substrate through the immobilized layer. To test the analytical performance of CTAB-Del/PyOx biosensors, chronoamperometric measurements were carried out using three electrode configurations at a constant potential of -0.7V in working buffer. The linear response for CTAB-Del/PyOx biosensor ranged from 0.01 to 0.50 mM with an equation of y=4.42x+0.004 (R2=0.998), and the limit of detection for glucose was calculated to be 0.081 μM (S/N=3).In order to confirm its practical use the CTAB-Del/PyOx biosensor was also applied for glucose analysis in various beverages. In addition, the antimicrobial activities of Del and CTAB-Del were screened in vitro by means of the disc diffusion susceptibility test, selecting a yeast, three different Gram-positive, andfive different Gram-negative bacteria. The obtained results showed a moderate antibacterial activity of CTAB-Del against Gram-positive bacteria.