Monolayers of natural and recombinant photosystem II on gold electrodes - Potentials for use as biosensors for detection of herbicides

Two methods for monolayer immobilization of photosystem II (PSII) isolated from thermophilic cyanobacteria Synechococcus elongatus and prospects for its use as a biosensor for detection of herbicides are reported: (i) immobilization based on recombinant (HiS)(6)-tagged PSII coupled with nickel-nitrilotriacetic acid (Ni-NTA) chelator monolayer on An electrode. (ii) immobilization based on the natural PSII coupled with the protein A-anti-DI antibody modified Au electrode. Here, Cysteamine (CYS)-self-assembled monolayer (SAM)-(NTA)-PSII monolayers were compared with traditional bovine serum albumin (BSA)-glutaraldehyde (GA)-PSII crosslinked get matrix and better performances of the derived electro-chemical biosensors were pointed out. Better diffusion of inhibitors and mediators resulted in improved sensitivity, velocity of the response, and lower 150 for herbicides.