title: Amperometric biosensor based on tyrosinase immobilized on a boron-doped diamond electrode.
abstract: A novel method has been developed to immobilize tyrosinase onto the surface of boron-doped diamond (BDD) electrode. The hydrogen-terminated BDD (HBDD) surface was first functionalized by photochemically linking vinyl groups of allylamine, producing covalently linked amine-terminated active BDD (ABDD) surface. Then the tyrosinase was immobilized onto the ABDD surface by carbodiimide coupling reaction. The amperometric response was measured as a function of concentration of phenolic compounds in 0.1M phosphate buffer solution (pH 6.5). The tyrosinase-modified ABDD electrode gave a linear response range of 1-175, 1-200 and 1-200 microM and sensitivity of 80.0, 181.4 and 110.0 mA M(-1)cm(-2) for phenol, p-cresol, 4-chlorophenol, respectively. Moreover, selective detection of dopamine (DA) in the presence of ascorbic acid (AA) has been demonstrated with the tyrosinase-modified ABDD electrode. Linearity was observed within the range of 5-120 microM. The above enzyme electrode could maintain 90% of its original activity after intermittent use for 1 month when storing in a dry state at 4 degrees C.
authors.affiliation: Laboratory of Photoelectro Chemistry, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Zhong Guan Cun, Haidian District, Beijing 100080, People's Republic of China.
authors.forename: Yan Li
authors.initials: YL
authors.lastname: Zhou
authors.forename: Ru Hai
authors.initials: RH
authors.lastname: Tian
authors.forename: Jin Fang
authors.initials: JF
authors.lastname: Zhi
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D001895:Boron / Q000737:chemistry*; D018130:Diamond / Q000737:chemistry*; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008839:Microelectrodes; D014442:Monophenol Monooxygenase / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure; D019800:Phenol / Q000032:analysis* / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D004800:Enzymes, Immobilized; D019800:Phenol; D018130:Diamond; D014442:Monophenol Monooxygenase; D001895:Boron