Nanomaterial-Based Electrochemical Immunosensors for the Detection of Mycobacterium avium subsp. paratuberculosis: Advancement, Challenges, and Future Perceptions.

Mycobacterium avium subsp. paratuberculosis (MAP) causes Johne's disease, a chronic infectious disease of ruminants associated with substantial economic losses in the livestock and dairy industries. Conventional diagnostic methods, including culture, polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay (ELISA), have limitations related to analysis time, laboratory requirements, infection stage, matrix effects, and diagnostic performance. Nanomaterial-based electrochemical immunosensors have emerged as promising platforms for rapid, sensitive, miniaturized, and potentially field-compatible MAP detection was conducted using PubMed, Scopus, Web of Science, and Google Scholar, primarily covering studies published between 2015 and 2026. The review evaluates metal nanoparticles, carbon-based nanomaterials, magnetic nanoparticles, and hybrid nanomaterials in relation to electrode surface area, biomolecule immobilization, electron transfer, signal generation, analytical performance, and real-sample validation. Key challenges includes matrix interference, nonspecific adsorption, stability, reproducibility, and standardization. Emerging approaches, including microfluidic integration, portable potentiostats, multiplexed sensing, flexible platforms, and artificial intelligence-assisted analysis. Overall, nanomaterial-based electrochemical immunosensors show considerable promise for MAP detection, but standardized validation using diverse field samples and robust manufacturing strategies is required before routine on-farm implementation.