QuickConc: A Rapid, Efficient, and Power-Free eDNA Concentration Method With Cationic-Assisted Capture.

Environmental DNA (eDNA) analysis is effective for non-invasive biodiversity monitoring, as it reveals species distribution and abundance without ecosystem disruption. Four key steps in eDNA analysis include water preservation, DNA capture, DNA extraction, and detection. Among these, the capture of eDNA has attracted significant research interest due to the variability of water samples. Although various methods for eDNA concentration have been developed, including filtration using disc or cartridge filters and passive samplers, no single method is universally applicable because of the variabilities of eDNA distribution and water characteristics, including turbidity levels. Therefore, the development of alternative eDNA concentration methods is important for advancing eDNA research. This study introduces QuickConc, a novel nucleic acid capture method that combines an enhancer of benzalkonium chloride with dispersed silica glass fibers, allowing better binding between nucleic acids and glass fibers. Our results indicate that this approach enhances eDNA capture and extraction efficiency by likely improving the interaction between glass fibers and eDNA. We tested QuickConc in three environments using qPCR and metabarcoding. QuickConc yielded 1.3-3 times more total eDNA compared to glass fiber filtration and Sterivex methods under our experimental settings. Species-specific qPCR results showed that QuickConc detected 2-10 times higher copy numbers compared to the other two methods. Metabarcoding analyses using the MiFish method revealed that the number of fish species detected in river water was higher with QuickConc compared to other methods, while in sea water, the number of fish species detected was similar to the glass fiber filtration and Sterivex methods. QuickConc offers new options for eDNA analysis for biodiversity monitoring and conservation strategies.