ENZYME SUPPORT SYSTEMS FOR BIOSENSOR APPLICATIONS BASED ON GOLD-COATED NYLON MESHES

A novel experimental protocol for enzyme immobilization based on the u se of a very permeable support is described and applied to the develop ment of an acetylcholinesterase (AChE) based biosensor. In this system , the enzyme was immobilized onto a gold-coated nylon mesh via a self- assembled monolayer of a bifunctional reagent, cystamine, preadsorbed onto the gold surface. This support has been characterized by optical microscopy and electrochemical measurements of permeability. In the as sembled biosensor, the AChE modified mesh was placed over a glassy car bon electrode and the response to 4-aminophenylacetate, used as substr ate, was monitored via the enzymatic reaction product, 4-aminophenol, by oxidation at +0.25 V vs. SSCE. This approach to biosensor design ha s been extended to the determination of organophosphorus and carbamate pesticides by their inhibition of AChE enzymatic activity. (C) 1996 E lsevier Science Limited