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A Reagentless Tyrosinase Biosensor Based on 1,6‐Hexanedithiol and Nano‐Au Self‐Assembled Monolayers
Author(s) -
Liu Zhimin,
Liu Jia,
Shen Guoli,
Yu Ruqin
Publication year - 2006
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200603512
Subject(s) - monolayer , tyrosinase , biosensor , nano , self assembled monolayer , nanotechnology , chemistry , materials science , organic chemistry , enzyme , composite material
Abstract An amperometric tyrosinase biosensor was developed via a simple and effective immobilization method using the self‐assembled monolayers (SAMs) technique. The organic monolayer film was first formed by the spontaneous assembly of thiolor sulfur compound (1,6‐hexanedithiol, HDT) from solution onto gold electrode. When these thiol‐rich surfaces were exposed to Au colloid, the sulfurs form strong bonds to gold nanoparticles, anchoring the clusters to the electrode substrate. After the assembly of gold nanoparticles layer, a new nano‐Au surface was obtained. Thus, the tyrosinase could be immobilized onto the electrode. The tyrosinase retained its activity well in such an immobilization matrix. The various experimental variables for the enzyme electrode were optimized. The resulting biosensor can reach 95% of steady‐state current within 10 s, and the trend in the sensitivity of different phenolic compounds was as follows: catechol>phenol> p ‐cresol. In addition, the apparent Michaelis–Menten constant ( K $\rm{ {_{m}^{app}})}$ and the stability of the enzyme electrode were estimated.