Researchers have developed a new type of membrane that could improve the ability to detect environmental DNA (eDNA) in marine environments, offering a better way to study the diversity of inshore fish. Environmental DNA refers to genetic material that organisms naturally release into their surroundings, such as through skin cells, mucus, or waste. By collecting and analyzing eDNA from water samples, scientists can identify the species present in an area without needing to physically capture or observe them. This method is especially useful for monitoring marine ecosystems and helping to conserve biodiversity. In marine environments, the concentration of DNA in seawater is extremely low, making it difficult for traditional methods to capture and detect it effectively. To address this challenge, a team of researchers from the City University of Hong Kong (CityUHK), along with collaborators from other universities, developed a functionalized membrane. This membrane is designed to more efficiently collect and detect eDNA from marine organisms. The study, titled "A tailored MoS₂ membrane with strong DNA-binding capability enhances aquatic biota detection through environmental DNA metabarcoding," was published in the journal National Science Review. The researchers coated a common membrane with an ultrathin layer of molybdenum disulfide (MoS₂), a two-dimensional material known for its unique properties. This modification allowed the membrane to bind to DNA more effectively, greatly improving its ability to capture eDNA from water. In both laboratory and field tests, the membrane showed significant improvements in detecting fish eDNA. In controlled experiments, it successfully identified several species of tropical coral reef fish, such as Acanthurus dussumieri and Chrysiptera cyanea. In field tests conducted at Hoi Ha Wan Marine Park, the membrane detected a broader range of fish species, including anchovies and carangid fish, without compromising the overall assessment of the fish community. These results highlight the membrane's potential for use in real-world marine monitoring efforts. The membrane is easy to produce and cost-effective, making it compatible with existing water sampling filtration systems. Its simplicity and efficiency suggest that it could be widely used in marine conservation, ecological surveys, and long-term environmental monitoring. It is especially valuable in areas with rich biodiversity that are difficult to survey directly. In China, the Ministry of Ecology and Environment is actively promoting the use of eDNA technology for biodiversity assessments, and this new membrane technology is expected to play a key role in advancing these efforts.