L-Cysteine functionalized magnetite nanoparticle adorned Ti₃C₂-MXene nanohybrid based screen printed immunosensor for...

Nanohybrid based non-invasive biosensing platforms are emerging as promising alternatives to detect biomarkers in complex and diverse bio-fluids toward ultrasensitive point-of-care diagnostics. Herein, we report the development of a highly sensitive, facile, non-invasive, label free, affordable, and innovative electrochemical screen printed immunosensor for identifying CYFRA 21-1, an established and crucial biomarker for oral cancer. Until now, no work has been reported utilizing a titanium carbide Ti₃C₂ MXene nanosheet and L-cysteine (L-Cyst) functionalized magnetite nanoparticle (MNPs) nanohybrid based immunosensor for electrochemical detection of CYFRA 21-1. The L-Cyst@MNPs/Ti₃C₂-MXene nanohybrid was synthesized via the co-precipitation method and later deposited on a gold screen printed electrode (GSPE) offering enhanced surface area and electrochemical properties. The nanohybrid modified GSPE was then surface immobilized with monoclonal antibodies (anti-CYFRA-21-1) to fabricate an anti-CYFRA-21-1/L-Cyst@MNPs/Ti₃C₂-MXene/GSPE immunoelectrode and the non-specific locations of the immunoelectrode were covered with bovine serum albumin (BSA). The spectroscopic, morphological, and structural analyses of the synthesized nanohybrid and the fabricated electrodes were performed using different analytical techniques. The electrochemical studies of modified electrodes were evaluated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The fabricated BSA/anti-CYFRA-21-1/L-Cyst@MNPs/Ti₃C₂-MXene/GSPE immunosensor has shown an excellent limit of detection of 0.023 ng mL^-1, a linear detection range of (0.5-30) ng mL^-1, a sensitivity of 277.28 μA (ng mL^-1)^-1 cm^-2 and a lower limit of quantification of 0.618 ng mL^-1 for electrochemical CYFRA 21-1 determination. Hence, this L-Cyst@MNPs/Ti₃C₂-MXene nanohybrid could also be explored as a potential candidate for determining other cancer biomarkers.