Self-assembled nano-hybrid composite based on Cu/CuXO nanoflower decorated onto hBNNS for high-performance and ultra-sensitive electrochemical detection of CEA biomarker

Synergistic combination of metal/metal oxide with semiconductor as nano-hybrid composites (NHC), exhibits unmatched potential for developing nano-biosensors with superior stability, sensitivity, and selectivity. In this study, we report the fabrication of hydrothermally synthesized 3D2D NHC based on self-assembled Cu/Cu_XO-hBNNS for label-free detection of Carcinoembryonic Antigen (CEA). A systematic investigation into the synthesis of Cu_XO-NF, hBNNS, and Cu/Cu_XO-hBNNS NHC was carried out using extensive spectroscopic and advanced nanoscale imaging techniques. Uniform deposition of Cu/Cu_XO-hBNNS films onto pre-hydrolyzed ITO electrodes was achieved at a low DC potential of 15 V using electrophoretic deposition (EPD). Optimum immunoelectrode efficacy was analyzed by monitoring antibody incubation time, electrolyte pH, and control study through FTIR and electrochemical techniques. Electrode study revealed remarkably improved surface chemistry upon Cu/Cu_XO integration with hBNNS, yielding ∼74 % and ∼ 31 % increase in CV and DPV response along with 3-fold increase in diffusion coefficient compared to bare hBNNS. The sensing response of the BSA/Anti-CEA/Cu/Cu_XO-hBNNS/ITO nano-biosensor detected CEA concentrations from 0 to 50 ng/mL utilizing [Fe(CN₆)^3-/4-] as a redox probe and demonstrated an exceptionally low limit of detection of 3.22 pg/mL (R² = 0.99998). Electrochemical clinical evaluation supported by ELISA test established that Cu/Cu_XO-hBNNS-based nano-biosensor demonstrates exceptional shelf life, low cross-reactivity, and superior recovery rates in human serum, highlighting its effectiveness for precise and reliable detection.