3,4‐Dihydroxy‐L‐phenylalanine for Preparation of Gold Nanoparticles and as Electron Transfer Promoter in H2O2 Biosensor |
| |
Authors: | Cong‐Cong Lu Min Zhang An‐Jun Li Xi‐Wen He Xue‐Bo Yin |
| |
Affiliation: | Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin, 300071, P.?R. China |
| |
Abstract: | 3,4‐Dihydroxy‐L ‐phenylalanine (dopa) and 2‐(3,4‐dihydroxyphenyl)ethylamine (dopamine) were investigated as reducing agent and stabilizer for synthesis of gold nanoparticles (AuNPs) by one‐pot heating of a solution of HAuCl4/dopa or dopamine. AuNPs with different sizes were obtained by controlling the mass ratios of HAuCl4/dopa or dopamine. The formation mechanism for AuNPs was also proposed. Immobilization of horseradish peroxidase (HRP) and promotion of its electron transfer by polydopa film were investigated for preparation of H2O2 biosensor. Alkaline dopa solution was dropped onto a gold electrode for the formation of polydopa film. HRP was immobilized on the polydopa film through interactions between heme centre of HRP and the amine and carboxyl groups in polydopa. The AuNPs embedded in the polydopa film improved the electron transfer efficiency. These two factors allowed successful development of a H2O2 sensor with HRP@polydopa‐AuNPs electrode. Due to its biocompatibility, the polydopa‐AuNPs film provided good retention of enzyme activity and long‐term stability of the sensor. A rapid catalytic response (3 s) and a linear range from 0.006 to 5.0 mmol L?1 were obtained for H2O2. This facile preparation strategy can be extended to other enzyme‐based biosensors. |
| |
Keywords: | Dopamine Polydopamine Gold nanoparticle Horseradish peroxidase H2O2 biosensor |
|
|