Analytical Sciences

Gold Nanoparticles-Enhanced Amperometric Tyrosinase Biosensor Based on Three-Dimensional Sol-Gel Film-Modified Gold Electrodes

Xianrui LI,* Tiankun REN,** Na WANG,* and Xueping JI*

*Department of Medical Chemistry, Hebei Medical University, Shijiazhuang 050017, P. R. China
**School of Pharmaceutical Sciences, Hebei Medical University, Shijiazhuang 050017, P. R. China

An amperometric biosensor for the determination of catechol was developed by immobilizing tyrosinase (tyr) on gold nanoparticles (AuNPs) and a (3-mercaptopropyl)-trimethoxysilane (MPTS) sol-gel three-dimensional network film-modified gold electrode. The AuNPs self-assembled in a sol-gel network provided an excellent microenvironment for an enzymatic reaction between tyrosinase and the substrate. It was found that the AuNPs could significantly affect the electron-transfer kinetics of the enzyme reaction, and remarkably enhance the electrochemical reduction of the corresponding o-quinones at the electrode surface. The nanostructured electrode showed high sensitivity (306.7 mA M⁻¹ cm⁻²) toward catechol, with an amperometric detection limit of 0.56 μM. The catalytic current of the biosensor was linear with the catechol concentration ranging from 1.7 to 96 μM with a correlation coefficient of 0.9992. The proposed biosensor exhibited a short response time, good anti-interferent ability, and excellent operational and storage stability.

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