title: Hybridization biosensor using di(2,2'-bipyridine)osmium (III) as electrochemical indicator for detection of polymerase chain reaction product of hepatitis B virus DNA.
abstract: A novel hepatitis B virus (HBV) DNA biosensor was developed by immobilizing covalently single-stranded HBV DNA fragments to a gold electrode surface via carboxylate ester to link the 3(')-hydroxy end of the DNA with the carboxyl of the thioglycolic acid (TGA) monolayer. A short-stranded HBV DNA fragment (181bp) of known sequence was obtained and amplified by PCR. The surface hybridization of the immobilized single-stranded HBV DNA fragment with its complementary DNA fragment was evidenced by electrochemical methods using [Os(bpy)(2)Cl(2)](+) as a novel electroactive indicator. The formation of double-stranded HBV DNA on the gold electrode resulted in a great increase in the peak currents of [Os(bpy)(2)Cl(2)](+) in comparison with those obtained at a bare or single-stranded HBV DNA-modified electrode. The mismatching experiment indicated that the surface hybridization was specific. The difference between the responses of [Os(bpy)(2)Cl(2)](+) at single-stranded and double-stranded DNA/TGA gold electrodes suggested that the label-free hybridization biosensor could be conveniently used to monitor DNA hybridization with a high sensitivity. X-ray photoelectron spectrometry technique has been employed to characterize the immobilization of single-stranded HBV DNA on a gold surface.
authors.affiliation: Department of Chemistry, Institute of Analytical Science, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, People's Republic of China. hxju@nju.edu.cn
authors.forename: Huang-Xian
authors.initials: HX
authors.lastname: Ju
authors.forename: Yong-Kang
authors.initials: YK
authors.lastname: Ye
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Zhao
authors.forename: Yong-Lin
authors.initials: YL
authors.lastname: Zhu
mesh_terms: D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives* / Q000737:chemistry*; D020137:Base Pair Mismatch; D015374:Biosensing Techniques; D004277:DNA, Single-Stranded / Q000032:analysis; D004279:DNA, Viral / Q000032:analysis* / Q000737:chemistry; D004563:Electrochemistry / Q000379:methods; D006046:Gold / Q000737:chemistry; D006515:Hepatitis B virus / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D009942:Organometallic Compounds / Q000737:chemistry*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000379:methods; D014965:X-Rays
chemical_list: D004277:DNA, Single-Stranded; D004279:DNA, Viral; D009942:Organometallic Compounds; D015082:2,2'-Dipyridyl; D006046:Gold; C085573:osmium bis(2,2'-bipyridine)chloride