A high-performance DNA biosensor based on the assembly of gold nanoparticles on the terminal of hairpin-structured probe DNA

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• 作者：Songling Li^aAuthor Vitae ; Weiwei Qiu^a ; ^bAuthor Vitae ; Xuan Zhang^aAuthor Vitae ; Jiancong Ni^a ; ^bAuthor Vitae ; Feng Gao^aAuthor Vitae ; Qingxiang Wang^a ; ^b ; ^{axiang236@126.com" class="auth_mail" title="E-mail the corresponding author}Author Vitae
• 关键词：Hairpin-like DNA ; Gold nanoparticles ; Electrochemical biosensor ; Electrochemical impedance spectra
• 刊名：Sensors & Actuators: B. Chemical
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：223
• 期：Complete
• 页码：861-867
• 全文大小：1147 K

文摘

An ultrasensitive electrochemical DNA biosensor has been developed based on the assembly of highly conductive gold nanoparticles (AuNPs) on the free terminal of hairpin-structured probe DNA. The hairpin probe DNA was first immobilized on a gold electrode surface through AuS bond. Then the thioglycolic acid (TGA) was grafted on the 3′-end of hairpin DNA via the carboxylic-amino condensation reaction. Followed by, the AuNPs were further attached through reaction with the thiol-group of TGA. Thus, a highly conductive biointerface with ultralow charge-transfer resistance was obtained. Quantitative analysis exhibited that the target DNA could be detected over the range from 1.0 × 10⁻¹⁷ to 1.0 × 10⁻¹¹ M. The detection limit was estimated to be 1.7 × 10⁻¹⁸ M. Also the biosensor showed good hybridization selectivity, stability and regeneration ability.