Precise antibiotic resistance gene degradation measurement via hydrogel digital loop-mediated isothermal amplification

Abstract The global overuse of antibiotics has accelerated the spread of antibiotic resistance genes (ARGs) in water and food systems. While quantitative PCR is widely used to monitor ARG degradation, its limitations in quantifying fragmented and unculturable ARGs hinder accurate comparisons. To address this, we implemented hydrogel digital loop-mediated isothermal amplification (LAMP)—a novel visual quantification platform enabling single-molecule detection by spatially confining LAMP reactions in hydrogel microchambers. This method was applied to evaluate the degradation kinetics of two critical ARGs (blaNDM from carbapenem-resistant Escherichia coli and mecA from methicillin-resistant Staphylococcus aureus) under food-relevant treatments: heat, ultrasound, UV254, TiO₂ photocatalysis, and light exposure (red/blue/white). Results revealed that mecA exhibited higher thermal sensitivity than blaNDM, with degradation rates escalating at elevated temperatures. Ultrasound degraded most of both ARGs within 20 min, while UV254 achieved near-complete inactivation in 2 min. TiO₂ photocatalysis showed moderate efficacy, with mecA being more susceptible. Red light induced degradation via thermal radiation, whereas blue/white light had negligible effects within 60 min. Our hydrogel digital LAMP system provides rapid, visual, and precise ARG quantification, offering significant potential for on-site monitoring in food safety control.