MXene-incorporated CNPs and Au@Pt with dual-electric signal outputs for accurate detection of Mycobacterium tuberculosis ESAT-6 antigen.

Rapid and effective detection of Mycobacterium tuberculosis (MTB) is the crux of minimizing tuberculosis (TB) spread. Consequently, a new electrochemical aptasensor based on dual-signal output for ultrasensitive detection of MTB early secreted antigenic target 6 (ESAT-6) antigen was developed. Especially, a new nanocomposite MXene/CNPs/Au@Pt was synthesized for signal generation and amplification. In this biosensing architecture, dual independent signal outputs were achieved by coupling the electrochemical redox activity of fullerene nanoparticles (CNPs) with the effective electrocatalytic activity of Au@Pt nanoparticles. MXene possesses a large specific surface area, allowing densely loaded of these two electroactive materials, further improved sensing capability. In addition, specific ESAT-6 antigen binding aptamers were attached to Au@Pt to create the tracer label. With a typical sandwich format along with the introduction of the gold nanoparticle-loaded molybdenum disulfide (MoS-Au) as the sensing interface, the limit of detection (LOD) of the proposed aptasensor was 2.88 fg mL (DPV measurement) and 13.50 fg mL (IT measurement), respectively, with a broad linear range of 100 fg mL to 50 ng mL. Significantly, it exhibited better specificity and accuracy with a sensitivity of 97.5% and a specificity of 96.7% to distinguish healthy donors, other lung diseases and TB patients compared to commercial ELISA assay, holding a promising prospect in clinical diagnosis.