New Membrane Makes It Easier to Detect Fish DNA Traces in Seawater

Scientists monitor marine life by analyzing environmental DNA, or eDNA — trace genetic material that organisms naturally release into water through skin cells, mucus and waste — allowing them to identify which species are present in a body of water without capturing or observing them directly. But DNA concentrations in seawater are extremely low, making it difficult for traditional membranes to capture it effectively. A research team from City University of Hong Kong (CityUHK), working with collaborators from several other universities, has developed a functionalized membrane that significantly improves the collection and detection of eDNA from marine organisms.

The team, led by Professor Kenneth Leung Mei-yee, director of the State Key Laboratory of Marine Environmental Health, and Professor Zeng Zhiyuan of the Department of Materials Science and Engineering, coated the surface of a common membrane with an ultrathin layer of the 2D material molybdenum disulfide (MoS2), enabling it to capture DNA in water more effectively. The study was published in the journal National Science Review.

In controlled laboratory experiments, the membrane accurately identified a variety of tropical coral reef fish, including Acanthurus dussumieri, Chrysiptera cyanea and Paracanthurus hepatus. In field testing at Hong Kong's Hoi Ha Wan Marine Park, the membrane detected a greater number of fish species, including anchovies, flathead gray mullet and carangid fish, without affecting the overall assessment of the fish community.

'The membrane is simple to prepare and cost-effective, and can be directly integrated into existing water sampling filtration processes,' Leung said, adding that it is expected to find future applications in marine conservation, ecological surveys and long-term environmental monitoring, particularly in marine areas that are rich in biological resources but difficult to survey.