Amplified detection of femtomolar DNA based on a one-to-few recognition reaction between DNA-Au conjugate and target DNA

Zhijuan Wang, Juan Zhang, Changfeng Zhu, Shixin Wu, Daniel Mandler, Robert S. Marks, Hua Zhang

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

A sensitive electrochemical DNA biosensor based on the amplification of Au nanoparticles (AuNPs) has been developed. The AuNPs were modified with two types of signaling reporter DNAs, i.e. a methylene blue probe (MB-probe 2-SH) and T10 with a methylene blue signaling molecule (MB-T10-SH), forming DNA-AuNP conjugates. The MB-probe 2-SH is complementary to the target DNA, while MB-T10-SH is not. The presence of MB-T10-SH reduces the cross-reaction between target DNA and MB-probe 2-SH on the AuNPs, resulting in increased sensitivity of the biosensor. In our assay, the DNA sensor is fabricated by immobilizing a capture probe on the surface of the Au electrode, which then hybridizes with the corresponding target DNA, and further hybridizes with a DNA-Au conjugate. The signal of MB is measured by differential pulse voltammetry, while the DNA-Au conjugate enables the detection of target DNA in the linear range of 10 -13 to 10-8 M with the detection limit as low as 50 fM.

Original languageEnglish
Pages (from-to)3110-3115
Number of pages6
JournalNanoscale
Volume6
Issue number6
DOIs
StatePublished - 21 Mar 2014

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