A handheld isothermal fluorescence detector for duplex visualization of aquatic pathogens via enhanced one-pot LAMP-PfAgo assay

Abstract

The expansion of large-scale aquaculture has exacerbated the challenge of aquatic diseases, resulting in substantial economic losses annually. Currently, traditional laboratory-based diagnostic methods are time-consuming and costly, hindering on-site testing for individual farmers. We address this issue by developing a state-of-the-art handheld isothermal nucleic acid amplification device (WeD-1) capable of fluorescence tracking of reactions and integrating it with an enhanced one-pot Prokaryotic Argonaute based nucleic acid detection method, enabling duplex visual detection of aquatic pathogens. WeD-1 is portable, reusable, user-friendly, and cost-effective, offering real-time smartphone interaction and enabling real-time fluorescence observation during the reaction. The enhanced one-pot Loop-Mediated Isothermal Amplification (LAMP)-PfAgo method, incorporating paraffin-encapsulated lyophilized PfAgo protein, achieves precise target-specific cleavage, significantly enhancing multiplex nucleic acid detection. This innovation streamlines on-site testing, negating the need for specialized laboratory conditions while ensuring an aerosol-free system. With newly developed and highly sensitive LAMP primer sets, our compact WeD-1/LAMP-PfAgo nucleic acid rapid testing system exhibits remarkable sensitivity, readily detecting aquatic pathogens with naked eyes from rapidly prepared fish and shrimp samples within 40 min, even when the Ct values are as high as 34.