Syntheses And Characterization Of N-Containing Compounds And Electrochemical Studies On Interaction Mechanism With DNA

In this article, series of N-containing compounds were synthesized andcoordinated with transitional metals, whose structures were characterized by IR, EAand X-ray crystallography methods. Cyclic voltammetry (CV) coupled with ultraviolet(UV) spectroscopy and fluorescence spectroscopy techniques were used to study theinteraction between these compounds and salmon sperm DNA to optimize conditions.These sensors were prepared by immobilizing single-stranded DNA probes ondifferent electrodes and using electroactive indicators to measure the hybridizationevents between the DNA probes and their complementary DNA fragments. Theelectrochemical DNA biosensor developed might have potential application indesigning of novel anti-AIDS drugs and diagnosis disease.(1) Three benzimidazole derivatives and the coordination complex weresynthesized by the condensation of o-diaminobenzene and characterized by elementalanalysis and IR spectra. Two single crystals of them were obtained and their structureswere determined by X-ray crystallography method. Compound 4a crystallizes in theorthorhombic system and compound 4b belongs to monoclinic system. The process of[Cd(C₇H₆N₂)₂]²⁺ on glassy carbon electrode might be a quasi-reversible reactioncontrolled neither by adsorption nor by diffusion. Cyclic voltammetry (CV) anddifferential pulse voltammetry (DPV) were used to investigate the interaction between[Cd(C₇H₆N₂)₂]²⁺ and salmon sperm DNA. The results show that the mode of theinteraction of DNA with [Cd(C₇H₆N₂)₂]²⁺ is interealative.(2) The Cu metal complex, [Cu(C₁₆H₁₄N₂O₂)], was synthesized and characterizedby elemental analysis (EA) and infrared spectrometry (IR). Cyclic voltammetry (CV)and differential pulse voltammetry (DPV) were used to investigate the interaction between [Cu(C₁₆H₁₄N₂O₂)] and salmon sperm DNA. When DNA was added, the peakcurrent of [Cu(C₁₆H₁₄N₂O₂)] was decreased and the peak potential was not changed. In0.2 mol·L^-1 B-R buffer solution, the binding ratio between [Cu(C₁₆H₁₄N₂O₂)] andsalmon sperm DNA was calculated to be 2:1 and the binding constant was 6.63x10⁵L².mol^-2.(3) A surface-based method for the study of the interaction of DNA withredox-active 2-aminophenoxazin-3-one is described. The study was carried out usingglassy carbon electrode (GCE) modified with 21-met single stranded oligonucleotidesrelated to hepatitis B virus sequence via covalent immobilization and2-aminophenoxazin-3-one as an electrochemical indicator. Electochemical detectionwas performed by cyclic voltammetry and differential pulse voltammetry over thepotential range where the AP was redox active. Numerous factors affecting the probeimmobilization, target hybridization, and indicator binding reactions were optimized tomaximize the sensitivity and speed the assay time. With this approach, a sequence ofthe hepatitis B virus from human blood could be quantified over the ranges from3.53×10^-7 to 1.08×10^-6 mol·L^-1 with a linear correlation of r=0.9963 and a detectionlimit of 7.0x10^-8 mol·L^-1 (S/N=3). The AP signal observed from probe sequencebefore and after hybridization with four bases mismatch containing sequence is lowerthan that observed after hybridization with complementary sequence.(4) The electrochemical behavior of aquabis(1,10-phenanthroline)copper(â…¡)perchlorate [Cu(H₂O)(phen)₂] 2CIO₄, where phen=1,10-phenanthroline, on binding toDNA at a glassy carbon electrode (GCE) and in solution, was described. Cyclicvoltammetry (CV) coupled with ultraviolet (UV) spectroscopy and fluorescencespectroscopy techniques were used to study the interaction between[Cu(H₂O)(phen)₂]²⁺ and salmon sperm DNA. Results showed that [Cu(H₂O)(phen)₂]²⁺had excellent electrochemical activity on the GCE with a couple quasi-reversible redoxpeaks. The interaction mode between [Cu(H₂O)(phen)₂]²⁺ and double-strand DNA(dsDNA) was identified to be intercalative binding. In 0.2 mol·L^-1 B-R buffer solution,the binding ratio between [Cu(H₂O)(phen)₂]²⁺ and salmon sperm DNA was calculatedto be 1:1 and the binding constant was 1.34x10⁵ L.mol^-1. An electrochemical DNAbiosensor was developed with covalent immobilization of human immunodeficiencyvirus (HIV) probe single-strand DNA (ssDNA) on the modified GCE. Numerousfactors affecting the probe immobilization, target hybridization, and indicator bindingreactions were optimized to maximize the sensitivity and speed the assay time. Withthis approach, a sequence of the HIV could be quantified over the ranges from 3.1×10^-9to 7.8x10^-11 mol with a linear correlation of r=0.9987 and a detection limit of1.3×10^-11 mol·L^-1. The electrochemical DNA sensor developed might have the potential application in diagnosis of diseases.(5) In this study, an electrochemical DNA biosensor was developed based on therecognition of target DNA by hybridization detection. The study was carried out usingglassy carbon electrode (GCE) modified with lable-free 21-mer single strandedoligonucleotides related to hepatitis B virus sequence via covalent immobilization and[Cu(dmp)(H₂O)Cl₂] (dmp = 2,9-dimethy1-1,10-phenanthroline) as an electrochemicalindicator, whose sizes are comparable to those of the small groove of nativedouble-duplex DNA. The method, which is simple and low cost, allows theaccumulation of copper complex within the DNA layer. Electochemical detection wasperformed by cyclic voltammetry and differential pulse voltammetry over the potentialrange where the [Cu(dmp)(H₂O)Cl₂] was active. Numerous factors affecting the probeimmobilization, target hybridization, and indicator binding reactions were optimized tomaximize the sensitivity and speed the assay time. With this approach, a sequence ofthe hepatitis B virus could be quantified over the ranges from 8.82x10^-8 to 8.82x10^-7mol.L^-1 with a linear correlation ofr=0.9937 and a detection limit of 7.0x10^-8 mol·L^-1.The [Cu(dmp)(H₂O)Cl₂] signal observed from probe sequence before and afterhybridization with four bases mismatch containing sequence is lower than thatobserved after hybridization with complementary sequence.(6) The complex [Co(phen)₂IP].2C1O₄·3H₂O, where phen=1,10-phenanthrolineand IP=imidazo[f][1,10]phenanthroline, was synthesized and characterized byinfrared spectrometry (IR). Cyclic voltammetry (CV) was used to investigate theinteraction between [Co(phen)₂IP]²⁺ and salmon sperm DNA. [Co(phen)₂IP]²⁺ hadexcellent electrochemical activity on the glassy carbon electrode (GCE) with a couplequasi-reversible redox peaks. In 0.2 mol·L^-1 B-R buffer solution, the binding ratiobetween [Co(phen)₂IP]²⁺ and salmon sperm DNA was calculated to be 1:1 and thebinding constant was 3.74x10⁵ L.mol^-1. A human immunodeficiency virus (HIV) DNAbiosensor was developed .by immobilizing covalently single-stranded HIV DNAfragments to a modified glassy carbon electrode (GCE). The surface hybridization ofthe immobilized single-stranded HIV DNA fragment with its complementary DNAfragment was evidenced by electrochemical methods using [Co(phen)₂IP]²⁺ as a novelelectrochemical indicator, with a detection limit of 27 pmol and a linear range from1.6×10^-10 to6.2×10^-9 mol.