In Situ Ag-Seeded Lamellar Ti₃C₂ Nanosheets: An Electroactive Interface for Noninvasive Diagnosis of Oral Carcinoma via Salivary TNF-α Sensing

In the fast-paced quest for early cancer detection, noninvasive screening techniques have emerged as game-changers, offering simple and accessible avenues for precession diagnostics. In line with this, our study highlights the potential of silver nanoparticle-decorated titanium carbide MXene nanosheets (Ti₃C₂_AgNPs) as an electroactive interface for the noninvasive diagnosis of oral carcinoma based on the prevalence of the salivary biomarker, tumor necrosis factor-α (TNF-α). An in situ reduction was utilized to synthesize the Ti₃C₂_AgNPs nanohybrid, wherein Ti₃C₂ acts as the reducing agent, and the resulting nanohybrid was subjected to various characterization techniques to examine the optical, structural, and morphological attributes. The results revealed that spherical AgNPs formed on the surface of Ti₃C₂ MXene nanosheets by virtue of the low-valent Ti species present in Ti₃C₂, which facilitated the reduction of AgNO₃ to AgNPs. Furthermore, the electrochemical characterization of the nanohybrid-modified screen-printed electrode (Ti₃C₂_AgNPs/SPE) indicated enhanced heterogeneous electron transfer kinetics. With these encouraging results, the Ti₃C₂_AgNPs nanohybrid was employed as an immobilization matrix for TNF-α antibodies and applied for electrochemical sensing. Analytical studies of the fabricated immunosensor, conducted by differential pulse voltammetry (DPV), exhibited a broader linear range (1 to 180 pg mL^-1), a low limit of detection (0.97 pg mL^-1), and high sensitivity (1.214 μA mL pg^-1 cm^-2) and specificity, even in artificial saliva, indicating its reliability for oral carcinoma diagnosis. Therefore, the Ti₃C₂_AgNP nanohybrid seems a promising candidate for the effective sensing of TNF-α and could also be explored for other biomarkers.