Use of chitosan membrane from the carapace of the soldier crab Mictyris brevidactylus for biosensor construction.

Glucose oxidase (EC 1.3.4.3) was immobilized on chitosan membrane (<0.1 mm in thickness) prepared from the carapace of the soldier crab Mictyris brevidactylus. A glucose electrode was constructed by covering a platinum electrode (2.0 mm in diameter) with the enzyme membrane. The enzyme electrode sensed glucose amperometrically (1.0 micro A/mM, with linear range up to 0.5 mM, r = 0.999) when positively imposed with 0.6 V against an Ag/AgCl reference electrode. The glucose biosensor was sensitive (<0.1 micro M, S/N > 3), reproducible (CV for 55 micro M glucose <3%, n = 5), reagentless, and durable for months.