In Situ Ag-Seeded Lamellar Ti<sub>3</sub>C<sub>2</sub> Nanosheets: An Electroactive Interface for Noninvasive Diagnosis\nof Oral Carcinoma via Salivary TNF‑α Sensing

In\nthe fast-paced quest for early cancer detection, noninvasive\nscreening techniques have emerged as game-changers, offering simple\nand accessible avenues for precession diagnostics. In line with this,\nour study highlights the potential of silver nanoparticle-decorated\ntitanium carbide MXene nanosheets (Ti<sub>3</sub>C<sub>2</sub>_AgNPs)\nas an electroactive interface for the noninvasive diagnosis of oral\ncarcinoma based on the prevalence of the salivary biomarker, tumor\nnecrosis factor-α (TNF-α). An in situ reduction was utilized\nto synthesize the Ti<sub>3</sub>C<sub>2</sub>_AgNPs nanohybrid, wherein\nTi<sub>3</sub>C<sub>2</sub> acts as the reducing agent, and the resulting\nnanohybrid was subjected to various characterization techniques to\nexamine the optical, structural, and morphological attributes. The\nresults revealed that spherical AgNPs formed on the surface of Ti<sub>3</sub>C<sub>2</sub> MXene nanosheets by virtue of the low-valent\nTi species present in Ti<sub>3</sub>C<sub>2</sub>, which facilitated\nthe reduction of AgNO<sub>3</sub> to AgNPs. Furthermore, the electrochemical\ncharacterization of the nanohybrid-modified screen-printed electrode\n(Ti<sub>3</sub>C<sub>2</sub>_AgNPs/SPE) indicated enhanced heterogeneous\nelectron transfer kinetics. With these encouraging results, the Ti<sub>3</sub>C<sub>2</sub>_AgNPs nanohybrid was employed as an immobilization\nmatrix for TNF-α antibodies and applied for electrochemical\nsensing. Analytical studies of the fabricated immunosensor, conducted\nby differential pulse voltammetry (DPV), exhibited a broader linear\nrange (1 to 180 pg mL<sup>–1</sup>), a low limit of detection\n(0.97 pg mL<sup>–1</sup>), and high sensitivity (1.214 μA\nmL pg<sup>–1</sup> cm<sup>–2</sup>) and specificity,\neven in artificial saliva, indicating its reliability for oral carcinoma\ndiagnosis. Therefore, the Ti<sub>3</sub>C<sub>2</sub>_AgNP nanohybrid\nseems a promising candidate for the effective sensing of TNF-α\nand could also be explored for other biomarkers.