Three-dimensional electrochemical DNA biosensor based on 3D graphene-Ag nanoparticles for sensitive detection of CYFRA21-1 in non-small cell lung cancer

Many studies have confirmed that CYFRA21-1 DNA is a sensitive and specific marker for non-small cell lung cancer (NSCLC). Hence, there is an urgent need to explore new strategies for early diagnosis of CYFRA21-1 DNA in the clinic. Here, we report a three-dimensional electrochemical DNA biosensor based on 3D graphene functionalized with Ag nanoparticles for sensitive DNA detection. The highly conductive nanocomposite layer was characterized by using scanning and transmission electron microscopy, contact angle analysis, and cyclic voltammetry. The 3D GF/AgNPs provide a favorable microenvironment to retain the bioactivity of immobilized probe ssDNA and effectively promote electron transfer owing to their excellent biocompatibility and good conductivity. Under optimal conditions, the biosensor could detect target DNA down to 1.0 x 10(-14) M with high sensitivity, and the peak currents were linear with the logarithm of the concentrations of target DNA from 1.0 x 10(-14) to 1.0 x 10(-7) M. Furthermore, in clinical trials, the three-dimensional biosensing system detected CYFRA21-1 DNA in real lung cancer samples with satisfactory results. Our research suggests that this newly developed 3D electrochemical biosensor is a promising method for potential use in the early diagnosis of lung cancer patients. (C) 2017 Elsevier B.V. All rights reserved.