Research On HIV Electrochemical Biosensing Based On Cascade Strand Displacement Along With Non-enzymatic Recycling Amplification

Objective:Human Immunodeficiency Virus(HIV)can cause human acquired immunodeficiency syndrome(AIDS).According to the World Health Organization,early diagnosis of HIV is of crucial importance in controlling its spread.In this study,cascade amplification of the toehold-mediated strand displacement reaction(TMSDR)and non-enzymatic target recycling amplification(TRA)were used to amplify the signal.The constructed dual-signal electrochemical biosensor can achieve high sensitivity and specificity of HIV-related genes detection for early diagnosis.Methods:1.Construction and characterization of the electrochemical biosensor: target promotes cascaded toehold-mediated strand displacement reactions,while simultaneously initiating non-enzymatic target cycling for signal amplification.2.Condition optimization of the electrochemical biosensors: the reaction conditions that influence the detection were optimized,including the concentration and the fixed time of the detection probe,the proportion of the reactants,the reaction equilibrium time and the temperature.3.Performance evaluation of the electrochemical biosensor: the square wave voltammetry(SWV)was used as the electrochemical detection method to evaluate the linear detection range,sensitivity,specificity,accuracy and repeatability of the sensor.Results:1.Different methods were used to prove that the designed method was feasible and the sensor was successfully constructed.2.The electrochemical biosensor based on TMSDR and non-enzyme TRA possessed a linear detection range of 1 pM to 10 nM and a detection limit of 0.88 pM(S/N=3).The sensor exhibited good specificity that can identify single-base mismatch.In addition,it also showed excellent accuracy and reproducibility.Conclusion:This study constructed an electrochemical biosensor for highly sensitive and specific detection of HIV-1 related gene.The sensor constructed in this study possessed dual signal,non-enzymatic amplification and mild experimental conditions.The cascaded strand displacement reaction and dual signal recognition ensure that the specificity of the method can identify single base mismatch.It also showed good detection ability in diluted human serum,indicating that it has the ability of detection in complex samples.Furthermore,by changing the sequence of the detection probe,other nucleic acids can be detected,so it has a good potential and value in nucleic acid detection.