Three-dimensional graphene-like homogeneous carbon architecture loaded with gold-platinum for the electrochemical detection of circulating tumor DNA

The analysis of circulating tumor DNA (ctDNA) turns out to be increasingly significant considering its potential value in the clinical diagnosis of cancer. Herein, a ctDNA electrochemical biosensor was developed with a low detection limit and high selectivity by using three-dimensional graphene-like homogeneous carbon architecture (3D-GHC600) loaded with gold-platinum (AuPt). The 3D-GHC600 was derived from the annealing process of copper-based metal-organic framework (denoted as Cu-BTC) at the optimal temperature (600 °C), which includes the merits of large area, rich mesopores, homogeneous size and morphology, and 3D structure. AuPt was formed on the 3D-GHC600 surface via an in-situ reduction reaction. Characterizations demonstrated that the resultant composite catalyst (AuPt/3D-GHC600) was prepared successfully and exhibited remarkable electrochemical properties. Further, the catalyst was used as a label of signal probes (SPs) to form SPs-label. The hybridization reactions were completed by layer-by-layer recognition of capture probes (CPs), target DNA (tDNA), and SPs-label on the electrode, thus forming a sandwich-like structure. The current signals of the SPs-label toward the electrocatalytic reduction of H2O2 were recorded in all tests for tDNA analysis. Accordingly, this recommended biosensor of tDNA showed good performance including a wide linear range of 10−8 M − 10−17 M with a detection limit of 2.25 × 10−18 M (S/N = 3), excellent selectivity for the recognition of different interferences, satisfying reproducibility, good stability, and outstanding recovery. These results demonstrated the promising application of the biosensor in the detection of ctDNA.