Objective To construct a novel enzyme-free colorimetric biosensor(T-CHA)based on tri-ple-helix molecular probe(THMP)and catalytic hairpin assembly(CHA)reaction for visual detection and precise quantitative analysis of low-abundance alpha-fetoprotein(AFP).Methods The absorbance produced by AFP induced T-CHA system was recorded by gel electrophoresis and ultraviolet-visible spectrophotometer to evaluate the feasibility of T-CHA strategy.The molar concentration ratio of THMP and CHA,reaction time of CHA,temperature and pH value of buffer solution were optimized respectively.The color reaction of T-CHA was induced by different concentrations of AFP to explore the detection efficiency of T-CHA.Results Under the op-timal experimental conditions,the logarithmic values of AFP at different concentrations showed a linear rela-tionship from 5 μg/mL to 10 ng/mL,and the detection limit was 2.29 μg/mL.The T-CHA system could com-plete accurate quantitative analysis of low abundance AFP and visual free-labeled detection within 105 min,moreover the sensitivity of T-CHA was superior to that of ELISA.Conclusion Utilizing the low background leakage of THMP and the high catalytic efficiency of CHA,the T-CHA system could realize the early accurate diagnosis of hepatocellular carcinoma,moreover which has a certain application prospect in the real time detec-tion.
维普
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