hydrogen peroxide sensor based on horseradish peroxidase-凯发网

a novel strategy to construct a sensitive amperometric sensor of h2o2 was described. horseradish peroxidase (hrp) wassuccessfully immobilized on nanometer-sized au colloids, which were supported by thiol-tailed groups of cysteaminemonolayer. the thiol-tailed groups were formed through the covalent binding of glutaraldehyde on a cysteamine-modifedgold electrode. with the aid of the catechol mediator in the solution, hrp-labeled au colloids displayed excellentelectrocatalytical response to the reduction of h2o2, which increased with decreasing size of au colloids. the sensorsresponded to h2o2 in the concentration range of 0.39 mm-0.33 mm, and reached 95% of the steady-state current in less than5 s with the detection limit of 0.15 mm. the response showed a michaelis-menten behavior at larger h2o2 concentrations.the kappm values for the sensors based on different sized hrp-labeled au colloids (colloid a-d) were found to be 0.11, 0.094,0.054 and 0.064 mm, respectively. the low kappm values demonstrated that hrp immobilized on au colloids exhibited a highaf