Enzyme-powered nanomotor probes for enhanced sensitivity in lateral flow immunoassay of aflatoxin B₁

In this study, we report the development of a β-galactosidase-powered Janus nanomotor probe for the active, rapid, and ultrasensitive detection of aflatoxin B₁ (AFB₁) in milk via lateral flow immunoassay (LFIA). The self-driven nanomotor system (PASNMs) was prepared by constructing Au-PAA/mSiO₂ Janus particles through surface tension adjustment, followed by selective gold domain modification with methoxy-poly(ethylene glycol)-thiol (PEG) and immobilization of monoclonal antibodies (Abs) and β-galactosidase on the mSiO₂ surface. The autonomous propulsion of PASNMs, powered by enzymatic hydrolysis of the substrate, significantly enhanced binding kinetics and target accessibility within the LFIA platform. Under optimized assay conditions, the PASNM-based LFIA displayed a broad linear response range (0.12-6.4 ng/mL) with a low detection limit of 0.086 ng/mL for AFB₁, surpassing the sensitivity of conventional AuNPs-based LFIA. Importantly, the assay demonstrated reliable performance for the detection of AFB₁ in spiked milk samples, highlighting its potential for rapid and sensitive mycotoxin screening in complex food matrices.