Adenine/Au complex-dependent versatile electrochemical platform for ultrasensitive DNA-related enzyme activity assay

We present a novel and simple versatile electrochemical platform for investigating some DNA-related enzymes activity based on Au(III)-coordinated adenine complex (noted as Adenine/Au complex). The synthesized Adenine/Au complex, which possesses good biocompatibility, active electrochemical performance and strong bio-affinity, enables the construction of electrochemical biosensor and further concurrently being exploited for probing DNA-related enzyme activity. The significant strategy is based on three favorable properties: the dazzling polymeric ability of terminal deoxynucleotidyl transferase (TdT); the strong adsorption interaction between TdT-yielded T-rich DNA with Adenine/Au complex; the unique electro-catalytic property of Adenine/Au complex. Here, the change in electrochemical response depends on the concentration of TdT or alkaline phosphatase (ALP), so the same novel electrochemical sensor for detecting TdT or ALP can be established with a lower detection limit. Nay, the two developed biosensors display high selectivity, good reproducibility, stability and applicability in inhibitor or real sample investigations. These results prove that the presented Adenine/Au complex gives new insight in multiple-functionally biosensing, further promoting the potential application of Adenine/Au complex-relevant nano-materials in clinical diagnosis.