title: Visual detection of single-base mismatches in DNA using hairpin oligonucleotide with double-target DNA binding sequences and gold nanoparticles.
abstract: We describe a hairpin oligonucleotide (HO) with double-target DNA binding sequences in the loop and 11-base in the stem for visual detection of single-base mismatches (SBM) in DNA with highly specificity. The thiol-modified HO was immobilized on gold nanoparticle (Au-NP) surface through a self-assembling process. The strategy of detecting SBM depends on the unique molecular recognition properties of HO to the perfect-matched DNA and SBM to generate different quantities of duplex DNA on the Au-NP surface, which are captured on the test zone of lateral flow test strip via the DNA hybridization reaction between the duplex DNA and preimmobilized DNA probe. Accumulation of Au-NPs produces the characteristic red bands, enabling visual detection of SBM. It was found that the ability of HO to differentiate perfect-matched DNA and SBM was increased dramatically by incorporating double-target DNA binding sequences in the loop of HO. The signal ratio between perfect-matched DNA and SBM was up to 28, which is much higher than that of conventional HO or molecular beacon. The approach was applied to detect the mutation sites, Arg142Cys and Gly529Ile, of transglutaminase 1 gene in autosomal recessive congenital ichthyosis. The results presented here show that the new HO is a potential molecular recognition probe for the future development of nucleic acid-based biosensors and bioassays. The approach can be used for point-of-care diagnosis of genetic diseases and detecting infectious agents or warning against bio-warfare agents.
authors.affiliation: Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou, PR China. dr.hyq@hotmail.com
authors.forename: Yuqing
authors.initials: Y
authors.lastname: He
authors.forename: Xibao
authors.initials: X
authors.lastname: Zhang
authors.forename: Sanquan
authors.initials: S
authors.lastname: Zhang
authors.forename: Mak Ka Long
authors.initials: MK
authors.lastname: Kris
authors.forename: Fong Chi
authors.initials: FC
authors.lastname: Man
authors.forename: Abdel-Nasser
authors.initials: AN
authors.lastname: Kawde
authors.forename: Guodong
authors.initials: G
authors.lastname: Liu
mesh_terms: D020137:Base Pair Mismatch; D006046:Gold / Q000737:chemistry; D006801:Humans; D007057:Ichthyosis / Q000175:diagnosis*; D055029:Inverted Repeat Sequences; D053768:Metal Nanoparticles / Q000737:chemistry; D009841:Oligonucleotides / Q000737:chemistry*; D011503:Transglutaminases / Q000032:analysis / Q000235:genetics
chemical_list: D009841:Oligonucleotides; D006046:Gold; D011503:Transglutaminases; C105804:transglutaminase 1