Polydopamine functionalized Ti₃AlC₂ MAX based electrochemical biosensor for early and sensitive detection of Mycobacterium tuberculosis

MAX phase materials have attracted considerable attention for a variety of applications, including high temperature structures and coatings, electric contacts, heat exchangers, concentrated solar power, catalysis, owing to their versatile properties that include high corrosion-resistance and mechanical strength, tunable surface kinetics, excellent thermal and radiation stability, etc. However, chemically engineered MAX phase materials are yet to be explored in development of biosensing devices. Here, for the first time, we report the development of MAX-based electrochemical platform, functionalized with polydopamine (PDA), for the reliable detection of Mycobacterium tuberculosis (MTB), a high-risk infectious pathogen that is spreading at an alarming rate regardless of age. The probe DNA immobilizes onto the surface of MAX/PDA via avidin-biotin coupling to construct ssDNA/avidin/MAX/PDA modified biosensing electrode. Cyclic voltammetry and differential pulse voltammetry results confirm the high charge transfer kinetics, good redox behavior, and excellent stability in modified electrode. Moreover, modified biosensing electrode attains extremely low detection limit of 0.1 attomolar, excellent sensitivity of 1.67 x 10(-4) mA mu M-1, and high selectivity with low response time towards MTB. The applicability of developed PDA functionalized MAX bio-electrodes may be extended for the detection of other infectious diseases, thus signifying how crucial is the present discovery from the perspective of controlling conventional and emerging infectious diseases and probing critical biomarkers.