A label-free electrochemical biosensor for detection of HIV related gene based on interaction between DNA and protein

Non-invasive early diagnosis of HIV is an important and effective means to reduce death from this disease. In this manuscript, we describe a method using a novel label-free electrochemical DNA biosensor for HIV related gene diagnosis with ultrahigh sensitivity and selectivity. The DNA biosensor was based on the interaction of hybrid double-stranded DNA and protein. In the presence of target DNA, the target/probe hybridization encountered the NF-kB protein. Upon addition of HRP, they formed the sandwich-like DNA sensor. The formed sandwich-like ds/NF-κB/HRP complex effectively catalyzed the H2O2-mediated oxidation of TMB, accompanied by a changed color of the reaction solution and an increased electrochemical current signal. However, in the absence of target DNA, no duplex DNA could bind NF-kB protein or HRP to form the DNA sensor. By employing the above strategy, the DNA biosensor was able to gain an amplified electrochemical signal and thus detected as low as 7.05 pM target DNA. Due to the high selectivity of the method, the developed biosensor also exhibited high discrimination ability even against single-base mismatch. Combined with the advantages of electrochemical detection and its ready integration with microelectronics, the proposed electrochemical DNA biosensor might represent a promising path toward direct HIV detection at the point of care.