title: Ultrasensitive nucleic acid biosensor based on enzyme-gold nanoparticle dual label and lateral flow strip biosensor.
abstract: In this article, we describe an ultrasensitive nucleic acid biosensor (NAB) based on horseradish peroxidase (HRP)-gold nanoparticle (Au-NP) dual labels and lateral flow strip biosensor (LFSB). The results presented here expand on prior work (Mao et al., 2009a) by optimizing the preparation of HRP-Au-NP-DNA conjugates. It was found that sodium dodecyl sulfate (SDS) and the immobilization sequence of thiolated DNA and HRP on the Au-NP surface played very important roles to improve the sensitivity of the assay. After systematic optimization, the detection limit of current approach is 1000 times lower than that in prior work. Deposition of insoluble enzymatic catalytic product (red colored chromogen) on the captured Au-NPs at the test zone of LFSB offers a dramatic visual enhancement. Combining enzyme catalytic amplification with unique optical properties of Au-NPs, the NAB was capable of detecting of 0.01-pM target DNA without instrumentation. The NAB thus provides a rapid, sensitive, low-cost tool for the detection of nucleic acid samples. It shows great promise for in-field and point-of-care diagnosis of genetic diseases and for the detection of infectious agents.
authors.affiliation: Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou 510095, PR China.
authors.forename: Yuqing
authors.initials: Y
authors.lastname: He
authors.forename: Sanquan
authors.initials: S
authors.lastname: Zhang
authors.forename: Xibao
authors.initials: X
authors.lastname: Zhang
authors.forename: Meenu
authors.initials: M
authors.lastname: Baloda
authors.forename: Anant S
authors.initials: AS
authors.lastname: Gurung
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
authors.forename: Xueji
authors.initials: X
authors.lastname: Zhang
authors.forename: Guodong
authors.initials: G
authors.lastname: Liu
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004247:DNA / Q000032:analysis* / Q000235:genetics*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D008832:Microchemistry / Q000295:instrumentation*; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation*; D011934:Reagent Strips; D013194:Staining and Labeling / Q000379:methods
chemical_list: D011934:Reagent Strips; D006046:Gold; D004247:DNA