Disposable interference-free glucose biosensor based on an electropolymerised poly(pyrrole) permselective film Original Research Article

Miniaturised disposable amperometric biosensors for glucose determination in serum are described. A commercially available three-electrode system created on a planar corundum ceramic base was used as biosensor substrate and the working Pt electrode was modified by an electrogenerated overoxidised poly(pyrrole) film (PPYox). After the optimisation of the PPy layer synthesis, two different approaches were investigated for glucose oxidase (GOD) immobilisation: enzyme entrapment into the electropolymerised film by an ‘all-electrochemical’ procedure (PPYox/GOD) and gel-entrapment over the PPYox modified electrode by co-crosslinking with glutaraldehyde/bovine serum albumin (PPYox/GOD-gel). A comparison of the sensitivities to glucose, performed by dropping 50 μl of the sample solutions onto the relevant electrode systems, showed that both sensors have a linearity range extending up to 10 mM, though Pt/PPYox/GOD-gel sensor is more sensitive (168±15 versus 53±7 nAm/M). The two sensors showed remarkable anti-interferent selectivity, moreover the PPYox/GOD-gel sensor had also a good stability and could be used for flow injection analysis of glucose, with a linearity range extending up to 25 mM.