Study Of Electrochemical Biosensors Based On Ni Nanostructure/Boron Doped Diamond Electrodes

Detecting biological substance accurately and fast,such as amino acids or glucose,is important to medical diagnosis and food production.Biosensors,based on nanomaterials modified boron-doped diamond(BDD)electrodes,exhibit some merits in detection,such as high sensitivity,fast response and good anti-interference performance,so get wide application prospect.In this work,preparation of BDD electrodes,modification of nanomaterials and analytical test of the biosensors were carried out.Self-standing BDD films were deposited by electron assistant chemical vapor deposition(EACVD)system.The process and dynamic model of diamond growth were studied,and the influence of the concentrations of carbon source on crystal quality and deposition mechanism was discussed.That morphology,defect,conductivity and electrochemical properties of BDD were affected by the concentration of boron was studied,and mechanism of boron atom diffusion was discussed.The fabricated BDD electrodes exhibited wide potential window,low background current,fine stability and reversibility in electrochemical property test.Nanoporous nickel(NP-Ni)modified on the surface of BDD electrodes by cyclic voltammetry(CV)deposition got large specific surface area and effective catalytic property.The electrochemical behavior of L-alanine on the surface of NP-Ni/BDD electrodes was studied.The result showed that the biosensors based on NP-Ni/BDD electrodes,with a high sensitivity of 50?Am M-1cm-2,exhibited a linear range from 0.5 to 4.5 ?M in response current as a function of L-alanine concentration,and a detection limit of 0.01 ?M.The electrodes also showed good anti-interference performance and stability for alanine injection detection.Ni-NiO half nanotubes(Ni-NiO HNTs)were prepared on BDD surface by a novel and versatile template-based electrochemical imprinting method for the first time.The Ni-NiO HNTs/BDD electrodes for biosensors were tested in L-serine detection.The study showed that HNTs with its open profile possessed some better properties on favourable permeability,high charge transfer velocity channel and high effective catalytic oxidation.In L-serine detection,the electrodes got a sensitivity accessing to 330?AmM-1 cm-2,and the linear range for response current to L-serine concentration found to be from 0.199 to 6.542?M,with a detection limit of 0.10?M.The electrodes had special selectivity to L-serine with coexisting of other amino acids.The biosensors based on Ni-NiO HNTs/BDD electrodes exhibited accurate and fast capability in serine additive detection.Nanodiamond(ND)powder of high purity was prepared by heating oxidation treatment.The compound film of Ni nanosheets and ND was deposited on BDD by electrochemical deposition,and property of Ni-ND/BDD electrodes was tested in detection of glucose.The study showed that ND deposited on BDD surface improved modification rate of Ni nanosheets,and increased potential window of electrodes.Ni-ND/BDD electrodes exhibited high catalytic oxidation property in glucose detection.The response of the electrodes to glucose concentration exhibited a linear range in three different concentration regions of 0.1-1?M,1-7?M and1000-9000?M,and their sensitivities were 1140?AmM-1cm-2,132?AmM-1cm-2 and 2.3?AmM-1cm-2,with a detection limit of 0.05?M.Packaging technique of glucose sensors based on Ni-ND/BDD electrodes was improved,and the sensors showed some good properties in blood glucose detection,such as high sensitivity,fast response,low cost and easy to use.