A novel tyrosinase biosensor based on biofunctional ZnO nanorod microarrays on the nanocrystalline diamond electrode for detection of phenolic compounds

A novel tyrosinase biosensor based on biofuncational ZnO nanorod microarrays on the boron-doped nanocrystalline diamond (BDND) substrates was developed. The ZnO nanorod microarrays were firstly deposited on BDND thin film surfaces via a low-temperature solution method, and then ZnO nanorods were functionalized with the mixture of 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS) by a co-condensation approach, then tyrosinase was immobilized to amino-modification ZnO nanorod surfaces by the covalent binding. As-prepared tyrosinase biosensors were used for the detection of phenolic compounds. The tyrosinase-modified BDND electrode gave a linear response range of 1-175,1-150 and 1-150 mu M and sensitivity of 576.2, 339.3 and 287.1 mu A mmol(-1) cm(-2) for p-cresol, 4-chlorophenol and phenol, respectively. The low detection limit was estimated to be 0.1, 0.25 and 0.2 mu M (s(b)/m = 3), respectively. Therefore, the biolfunctional ZnO nanorod arrays have potential applications as platforms to immobilize other enzymes and bioactive molecules in biosensors. (c) 2009 Elsevier B.V. All rights reserved.