An L-glutamate amperometric biosensor based on redox polymer wired horseradish peroxidase and glutamate oxidase

A two-electrode configuration has been fabricated by depositing gold film on a polyethylene terephthalate (PET) substrate. The integrated reference electrode was obtained by screen-printing commercial silver and silver chloride paste on the gold electrode. The working electrode was modified by drop-coating a redox polymer formed of poly (4-vinylpyrodine) complexed with osmium (2, 2-bipyrridine)(2). The bienzyme, horseradish peroxidase (HRP and glutamate oxidase (GLOx), were immobilized in the redox matrix by the (poly(ethylene glycol) diglycidyl ether(PEGDGE) crosslinker. The optimized biosensor were characterized by a sensitivity of 37.5 mA(mol/L)(-1) cm(-2), a detection limit of 1.0 x 10(-6) mol/L, a response time of less than 16 s, and a correlation coefficient during a concentration ranged from 1.0 x 10(-6) mol/L to 1.0 x 10(-4) mol/L is 0.9998 (n = 9). The biosensor exhibits excellent reproducibility and stability, retaining more than 90% of its original activity over a period of one month. The simple fabrication of the biosensor can be used to determinate L-glutamate rapidly in food industry and clinical diagnose.