An efficient electrochemical nano-biosensor based on hydrothermally engineered ultrathin nanostructures of hexagonal boron nitride nanosheets for label-free detection of carcinoembryonic antigen

Abstract

Advancements in nanostructure engineering have evolved ultrathin geometry and controlled morphology in inorganic layered materials consequently endowing ultrahigh specific surface area, highly permeable mass transport channels, and bio-compatible, bio-sensitive, bio-selective sites that render them appealing candidate as nano-biosensor. In the present work, engineered nanostructures of hexagonal boron nitride nanosheets (h-BNNS) were harnessed as electroanalytical sensing platform for label-free detection of carcinoembryonic antigen (CEA). The cytotoxicity analysis carried using MTT assay on the HEK 293 human cell line revealed the bio-compatible nature of ultrathin h-BNNS. Structural and morphological studies of h-BNNS nanostructures were investigated by XRD, SEM, TEM, Raman, and UV–visible spectroscopic techniques. Further, electrophoretic deposition (EPD) technique was employed at low DC potential (20 V) to fabricate micro-electrodes of h-BNNS onto hydrolysed indium tin oxide (ITO) glass substrates. Hydrothermally exfoliated ultrathin h-BNNS terminated with –OH, –NH, and –BH groups specifically crosslinks as well as anchors monoclonal antibodies of CEA by utilising synergy of EDC-NHS and BSA corroborated by FT-IR and diffusivity measurement. Under optimised working condition, nano-biosensor exhibited highly sensitive response (24.84 μA mL/ng/cm²) and remarkable lower limit of detection (LOD) of 22.5 pg/mL with correlation coefficient of 0.99988 in a wide physiological range from 0 to 50 ng/mL. As-fabricated nano-biosensor displayed negligible cross-reactivity, excellent shelf life, and great clinical performance for detection of CEA in human serum samples.