Integrating MWCNTs-doped MXene with multi-spiral-channel architecture enables field effect transistor biosensor capable of ultrasensitive determination of methotrexate

Previous breakthroughs in biosensor diagnostics stem from engineering and nanocomposites. Accurately detecting low-abundance compounds such as methotrexate in complex biospecimens (e.g. serum) is an important clinical challenge. To address this issue, a MWCNTs-doped MXene-based multi-spiral-channel field-effect transistor (MMSFETs) biosensor was constructed for ultrasensitive quantification of methotrexate. Our integrated biosensor exhibited following merits: a) The synergetic performance of MXene and MWCNTs for enhanced transconductance (0.63 mS) and detection capability (methotrexate, linear range of 0.001–100 μM and LOD down to 0.352 nM); b) Favorable selectivity, stability (one month), reproducibility (RSD = 0.99%, n = 7) for biosensing of methotrexate; c) Acceptable clinical performances on comparisons of MMFETs against commercial Abbott automatic immunoluminescence instrument (ARCHITECT I1000): favorable linearity and correlation coefficient (YMMSFETs = 1.4305 × Xtargeted concentration + 4.3791 with R2 = 0.949), significant p value (7.68E-12 < 0.001) and diagnosis capability of AUC (0.9907). Those advantages are anticipated to pave an avenue to design of the FETs-based biosensor towards the point-of-care diagnostics applications.