Capture and Protection of Environmental DNA in a Metal-Organic Framework

Environmental DNA (eDNA) is released by organisms into their surroundings, enabling non-invasive species detection and biodiversity assessments without the need for direct observation. However, collection poses challenges due to the generally low abundance of eDNA and the presence of degradation agents, including enzymes, UV radiation, and microorganisms, rendering samples unstable. Active filtration, which is frequently used to capture eDNA in water, can be time-consuming and cumbersome in field conditions. Herein, a filter-free one-pot procedure for capturing eDNA with the metal-organic framework (MOF), zeolitic imidazolate framework 8 (ZIF-8), is examined. The method is evaluated on 15 mL water samples from diverse sources (aquarium, river, and sea). ZIF-8 forms in all with high capture efficiency (>98%) using spiked salmon DNA to represent eDNA. The DNA is resistant to degradation by endonucleases and UV light. In addition, it remains stable over time as a species-specific salmon quantitative polymerase chain reaction detected genomic DNA in all samples captured with the MOF to a maximum of 28 days at 37 °C while the untreated control samples were below the assay detection limit by day 6. These results highlight the efficacy of ZIF-8 capture in overcoming challenges associated with the preservation of eDNA obtained from aquatic environments.