Point-of-care Test Technology Study Based Carbon Nanotube/Gold Nanoparticle Nanocomposite

In this paper,we used carbon nanotube/gold nanoparticles(CNT/GNPs)nanocomposite as probe,combined with cotton thread to establish point-of-care test(POCT)biosensor for detecting of DNA sequence related disease and carcinoembryonic antigen(CEA)which is one of lung cancer biomarkers.The specific contents are as follows:(1)Study of novel nucleic acid analytical method based on carbon nanotube/gold nanoparticles nanocomposite and hairpin structure DNA sequenceThis paper described a novel hairpin structure DNA sequence functionalized carbon nanotube/gold nanoparticles nanocomposite(CNT/GNPs)probe,combined with cotton thread device for rapid,sensitive,visual and quantitative detection of target DNA sequence and discrimination of single base mismatched DNA related to a human genetic disease,hereditary tyrosinemia type I.A novel hairpin structure DNA is formed in presence of coralyne which can react with adenosine at both ends of DNA sequence.The thiol group and biotin group were labeled on 5' end and 3' end of hairpin structure DNA.The hairpin structure DNA is coated onto the surface of CNT/GNPs nanpcomposites by Au-S self-assembling to form CNT/GNPs nanocomposite probe.The streptavidin is dropped on the cotton thread to form test zone.The hairpin structure of DNA of CNT/GNPs nanocomposite reporter probe was opened by specific bind between DNA sequence.The biotin on 3' end of DNA probe was apart from the surface of CNT/GNPs nanocomposite and combined with SA on cotton thread test zone to form color band because of aggravation of CNT/GNPs.The color intensity of color band can realize the quantitative detection of target DNA sequence.CNT/GNPs reporter probe can greatly improve detection sensitivity compared with traditional GNPs reporter probe.According to systematic optimization,the response of the device was linear for the range of 1-100 n M,and the detection limit was estimated to be 0.44 n M(S/N?3).(2)Study of electrochemical detection technology for DNA based on carbon nanotube/gold nanoparticles nanocomposite probeThe paper introduced a novel analytical method based on CNT/GNPs nanocomposite combined electrochemical method for DNA detection.The formed progress of hairpin structure DNA and CNT/GNPs nanocomposite reporter probe and detection principle are similar with the first work.However,quantitative analytical method is electrochemical analytical detection technology,which is different from above.The quantitative detection of target DNA sequence is finished by dissolving GNPs of CNT/GNPs nanocomposite aggregated on cotton thread test zone using HBr-Br2 solution and adsorptive stripping voltammetry(ASV).CNT/GNPs functionalized with a hairpin structure DNA probe was used as a reporter probe instead of traditional gold nanoparticles,which can improve the sensitivity of the assay greatly.After systematic optimization,the novel nucleic acid test on cotton thread device was capable of detecting of 0.15 n M target DNA in less than 40 minutes.(3)Study of immunochromatographic assay device based cotton thread and carbon nanotube/gold nanoparticles nanocomposite probe for carcinoembryonic antigen detectionThis paper describes a low-cost,sensitive,rapid and visual immunochromatographic assay method based on CNT/GNPs nanocomposite combined with cotton thread device for carcinoembryonic antigen(CEA)detection.The CNT/GNPs nanocomposite reporter probe was formed by the combination of detection antibody(d Ab)and CNT/GNPs.A certain concentration of CEA was dropped on cotton thread to form test zone.The rapid,sensitive detection of CEA is based on the competition of a binding event between CEA in sample solution and CEA on cotton thread test zone to the d Ab on the surface of CNT/GNPs nanocomposite.Quantitative detection of CEA was performed using a traditional scanner and Image J software.The performance with respect to sensitivity of the method was greatly improved by 2-3 magnitudes comparing with traditional gold nanoparticles(GNPs)or carbon nanotubes(CNTs)as reporter probe.Under optimal conditions,the analytical device was capable of detecting 2.32 ng/m L(S/N?3)CEA which is sensitive enough for clinical diagnosis.