title: A sensitive DNA biosensor based on a facile sulfamide coupling reaction for capture probe immobilization.
abstract: A novel DNA biosensor was fabricated through a facile sulfamide coupling reaction. First, the versatile sulfonic dye molecule of 1-amino-2-naphthol-4-sulfonate (AN-SO3(-)) was electrodeposited on the surface of a glassy carbon electrode (GCE) to form a steady and ordered AN-SO3(-) layer. Then the amino-terminated capture probe was covalently grafted to the surface of SO3(-)-AN deposited GCE through the sulfamide coupling reaction between the amino groups in the probe DNA and the sulfonic groups in the AN-SO3(-). The step-by-step modification process was characterized by electrochemistry and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Using Ru(NH3)6(3+) as probe, the probe density and the hybridization efficiency of the biosensor were determined to be 3.18×10(13) strands cm(-2) and 86.5%, respectively. The hybridization performance of the biosensor was examined by differential pulse voltammetry using Co(phen)3(3+/2+) (phen=1,10-phenanthroline) as the indicator. The selectivity experiments showed that the biosensor presented distinguishable response after hybridization with the three-base mismatched, non-complementary and complementary sequences. Under the optimal conditions, the oxidation peak currents of Co(phen)3(3+/2+) increased linearly with the logarithm values of the concentration of the complementary sequences in the range from 1.0×10(-13)M to 1.0×10(-8)M with a regression coefficient of 0.9961. The detection limit was estimated to be 7.2×10(-14)M based on 3σ.
authors.affiliation: Department of Chemistry and Environment Science, Zhangzhou Normal University, Zhangzhou 363000, PR China. axiang236@126.com
authors.forename: Qingxiang
authors.initials: Q
authors.lastname: Wang
authors.forename: Yingtao
authors.initials: Y
authors.lastname: Ding
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Shulian
authors.initials: S
authors.lastname: Jiang
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.forename: Jiancong
authors.initials: J
authors.lastname: Ni
authors.forename: Fei
authors.initials: F
authors.lastname: Gao
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000706:statistics & numerical data*; D004247:DNA / Q000032:analysis*; D015342:DNA Probes / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D057230:Limit of Detection; D009284:Naphthols / Q000737:chemistry; D010618:Phenanthrolines; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017550:Spectroscopy, Fourier Transform Infrared; D013451:Sulfonic Acids / Q000737:chemistry
chemical_list: D015342:DNA Probes; D009284:Naphthols; D010618:Phenanthrolines; D013451:Sulfonic Acids; D004247:DNA; C446900:1-amino-2-naphthol-4-sulfonic acid; C025205:1,10-phenanthroline
keywords: 1-Amino-2-naphthol-4-sulfonic acid; DNA biosensor; Electrodeposition; Sulfamide coupling reaction