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BSA-stabilized Au clusters as peroxidase mimetics for use in xanthine detection

Author:
Wang, Xian-Xiang, Wu, Qi, Shan, Zhi, Huang, Qian-Ming
Source:
Biosensors & bioelectronics 2011 v.26 no.8 pp. 3614-3619
ISSN:
0956-5663
Subject:
biocompatibility, biosensors, blood serum, bovine serum albumin, colorimetry, detection limit, gold, graphene, humans, hydrogen peroxide, iron oxides, nanoparticles, oxidation, pH, peroxidase, temperature, urine, xanthine, xanthine oxidase
Abstract:
In this paper, we demonstrated that bovine serum albumin (BSA) stabilized Au clusters exhibited highly intrinsic peroxidase-like activity. Unlike nature enzymes, the BSA-Au clusters have strong robustness and can be used over a wide range of pH and temperature. Because of ultra-small size, good stability and high biocompatibility in water solution compare with other kinds of nanoparticles as peroxidase mimetics, such as Fe₃O₄, FeS or graphene oxide, it is more competent for bioanalysis. Furthermore, we make use of the novel properties of BSA-Au clusters as peroxidase mimetics to detect H₂O₂. The as-prepared BSA-Au clusters were used to catalyze the oxidation of a peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) by H₂O₂ to the oxidized colored product, and which provides a colorimetric detection of H₂O₂. As low as 2.0×10⁻⁸M H₂O₂ could be detected with a linear range from 5.0×10⁻⁷ to 2.0×10⁻⁵M via this method. More importantly, a sensitive and selective method for xanthine detection was developed using xanthine oxidase (XOD) and the as-prepared BSA-Au clusters. The detection limit of this assay for xanthine was 5×10⁻⁷M and the proposed method was successfully applied for the determination of xanthine in urine and human serum sample.
Agid:
914930