Electrochemical aptasensor for the detection of vascular endothelial growth factor (VEGF) based on DNA-templated Ag/Pt bimetallic nanoclusters

• Published in: Chinese chemical letters 2016-06, Vol.27 (6), p.920-926
• Main Authors: Fu, Xian-Ming, Liu, Zhi-Jing, Cai, Shu-Xian, Zhao, Yan-Ping, Wu, Dong-Zhi, Li, Chun-Yan, Chen, Jing-Hua
• Format: Article
• Language: English
• Subjects: Aptamer; DNA-templated Ag/Pt bimetallic nanoclusters; Electrochemical aptasensor; Enzyme mimics; Protein detection; Vascular endothelial growth factor (VEGF)
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2016.04.014

The as-synthesized DNA-templated Ag/Pt bimetallic nanoclusters have higher peroxidase activity and can effectively catalyze the H2O2-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB), which induces a significant increase of current signal and a blue color change in solution. Therefore, based on this specific property, a label-free and sandwich-type electrochemical aptasensor for the detection of VEGF with high sensitivity and selectivity was developed. [Display omitted] In this paper, the DNA-templated Ag/Pt bimetallic nanoclusters were successfully synthesized using an optimized synthetic scheme. The obtained DNA-Ag/Pt NCs have an ultrasmall particle size and excellent distribution. The DNA-Ag/Pt NCs show intrinsic peroxidase-mimicking activity and can effectively catalyze the H2O2-mediated oxidation of a substrate, 3,3′,5,5′-tetramethylbenzidine (TMB), to produce a blue colored product. Based on this specific property, we employed the aptamer of VEGF to design a label-free electrochemical biosensor for VEGF detection. Under the optimized experimental conditions, a linear range from 6.0pmol/L to 20pmol/L was obtained with a detection limit of 4.6pmol/L. The proposed biosensor demonstrated its high specificity for VEGF and could directly detect the VEGF concentration in human serum samples of breast cancer patients with satisfactory results. This novel electrochemical aptasensor was simple and convenient to use and was cost-effective and label-free in design, and would hold potential applications in medical diagnosis and treatment.