PCR-free electrochemical genosensor for Mycobacterium tuberculosis complex detection based on two-dimensional Ti3C2 Mxene-polypyrrole signal amplification

Abstract

Mycobacterium tuberculosis (M.tb) is a human pathogen due to its slow growth rate and fastidious nature. Tools that can accurately and rapidly track M.tb are vital for the effective treatment of tuberculosis (TB). In present study, a novel genosensor was established for the highly sensitive diagnosis of the specific DNA target inside IS6110 sequence of M.tb genome, using MXene nanosheets and polypyrrole as electrode materials. The multilayer Ti3C2Tx MXene, prepared from the synthesized Ti3AlC2 by delamination process using HCl + LiF solution, presented notable activity in electrocatalysis as an electrode material. Composition information and morphological features of synthesized Ti3C2Tx MXene were studied in detail. Density functional theory (DFT) was applied to explain the structural evolution of Mxene, polypyrrole, nucleotide base, polypyrrole-Mxene hybrid, and nucleotide base-polypyrrole-Mxene intercalation as well as describe their interactions. Under the optimized conditions, the suggested biosensor presented a linear range of 100 fM −25 nM and an excellent coefficient equals 0.9909 and LOD equals 11.24 fM. Experimental results confirmed that this biosensor possessed great sensitivity, stability, and selectivity. This biosensor efficiently determined M.tb in human sputum samples, together with high detection recoveries of 90.52–100.8%.