| In this paper, two benzimidazole compounds were synthesized and coordinated with transitional metals. The structures of those compands and their intermediates were characterized by elemental analysis, IR spectra, 1H NMR and X-ray crystallographic analysis. Cyclic voltammetry (CV) coupled with ultraviolet (UV) spectroscopy and fluorescence spectroscopy techniques were used to study the interaction between metal complex Cu(bzim)(H2O)Cl2 with electrochemical nature and salmon sperm DNA to optimize conditions. A"sandwich-type"sensor and MWNTs modified DNA sensor were prepared by immobilizing single-stranded DNA probe on the electrode and using an electroactive indicator to measure the hybridization events between the DNA probes and their complementary DNA fragments, which can improve the detection limit and sensitivitivy. A"sandwich-type double-enzyme-linked"DNA sensor was prepared by immobilizing two different kinds of enzyme-modified single-stranded DNA probes on the electrode to measure two different kinds of DNA at the same time.In the first chapter, the characters and application of benzimidazole compounds, the research of interaction between benzimidazole compounds and DNA, the design principle and the sorts of biosensor, especially the actuality of research, application, advantages, disadvantages and trends of development of biosensor were introduced.In the second chapter, with o-diaminobenzene as the original material, two series of compounds and one benzimidazole complex were synthesized. The compounds were characterized by elemental analysis, IR spectra and 1H NMR. Two single crystals of intermediates were obtained and their structures were determined by X-ray crystallography method.In the third chapter, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to study the interaction between Cu(bzim)(H2O)Cl2 and salmon sperm DNA. Results showed that the interaction mode between Cu(bzim)(H2O)Cl2 and double-strand DNA (dsDNA) was identified to be intercalative binding. An electrochemical DNA biosensor was developed with covalent immobilization of 21-mer and 27-mer probe single-strand DNA (ssDNA) on the modified GCE with Cu(bzim)(H2O)Cl2 as an electrochemical indicator. With this approach, a sequence of the 21-mer could be quantified over the ranges from 3.51×10-7 to 2.04×10-6 mol·L-1 with a detection limit of 9.52×10-8 mol·L-1. A sequence of the 27-mer could be quantified over the ranges from 1.96×10-7 to 2.23×10-6 mol·L-1 with a detection limit of 5.81×10-8 mol·L-1.In the fourth chapter, A"sandwich-type"sensor was prepared by immobilizing a long probe DNA probe on the electrode and hybirding with the reference DNA and target sequence with Cu(bzim)(H2O)Cl2 and [Co(phen)3(ClO4)3] as indicators. A sequence of the 48-mer could be quantified over the ranges from 1.32×10-7 mol·L-1 to 2.52×10-6 mol·L-1 with a detection limit of 2.32×10-8 mol·L-1. For the"sandwich-type"strategy, the ?I (difference between Cu(bzim)(H2O)Cl2 signal obtained from the presence of S2+S2' and that of S2' only) was linear with the amount of complementary oligonucleotide ranging from 2.63×10-8 to 2.52×10-6 M. The sandwich strategy showed higher sensitivity and wider linear range than those of using 21-mer probe sequence.In the fifth chapter, a MWNTs modified DNA sensor was prepared wih Cu(bzim)(H2O)Cl2 as indicator. With this approach, a sequence of the 21-mer could be quantified over the ranges from 3.94×10-9 to 1.56×10-6 mol·L-1 with a detection limit of 8.22×10-10 mol·L-1. It showed that ssDNA/DCE has a good selectivity via the differences of the DPV among bare GCE, ssDNA/DCE and dsDNA/GCE.In the sixth chapter, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate electrochemical action of enzymatic outcomes AP and phenol. A"sandwich-type double-enzyme-linked"DNA sensor was prepared by immobilizing two different NH2-modified capture probe and hybirding with complementary target DNA, complementary S1-biotin-avidin-HRP and S1-biotin-avidin-ALP, which can detect two different sequences at the same time. A sequence of the T1 could be quantified over the ranges from 3.32×10-7 to 1.59×10-6 mol·L-1 and from 8.53×10-10 to 1.6×10-8 mol·L-1 with a detection limit of 1.01×10-11 mol·L-1, and a sequence of the T2 could be quantified over the ranges from 2.7×10-7 to 1.3×10-6 mol·L-1 and from 6.81×10-10 to 1.3×10-8 mol·L-1 with a detection limit of 3.64×10-11 mol·L-1. Compared to the DPV curves of the enzymatic soultion 1 and 2, it showed that"sandwich-type double-enzyme- linked"DNA sensor has good sectivity.At last, it was summarized for the whole thesis. |
PDF Full Text Request