| Jun 24, 2026 |
Tiny water fleas reveal early warning signs of nanomaterial toxicity
Automated system analyzes heart rates of about 150 Daphnia magna per hour, enabling more sensitive detection of toxic effects at low concentrations in aquatic ecosystems.
(Nanowerk News) The Korea Research Institute of Standards and Science (KRISS) has developed a toxicity assessment system that automatically measures and analyzes the heart rate of the Daphnia magna. Capable of processing heart rate data from approximately 150 individuals per hour, the system can assess the toxic effects of pollutants at low concentrations more sensitively than conventional methods that rely on average values from a small number of specimens (Journal of Hazardous Materials, "High-throughput heart rate monitoring in Daphnia magna for sublethal ecotoxicological assessment").
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The technology is expected to help detect early warning signs of hazardous nanomaterials and environmental pollutants before more visible effects appear.
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Daphnia magna is easy to culture, offers high reproducibility, and has a transparent body, making it well suited for observing internal organs. For these reasons, it is widely used in aquatic toxicity assessment. The current international standard toxicity test, OECD Test No. 202: Daphnia sp. Acute Immobilisation Test, evaluates toxicity by visually determining whether the organism’s swimming ability has been impaired.
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However, this approach has limitations, as measurement results can vary depending on the observer’s subjective judgment. Heart rate measurement has gained attention as a quantitative indicator that can complement these limitations, but it has been difficult to accurately measure the rapid heartbeat of Daphnia magna, which beats approximately six to eight times per second, with the naked eye.
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To address this challenge, the KRISS research team developed a system that automatically measures and analyzes the heart rate of Daphnia magna. The system captures high-speed images of the heart region of Daphnia magna immobilized on cotton fabric and records repeated changes in light intensity to automatically calculate heart rate. Measurement data are generated in real time by the system and can then be analyzed to detect toxic responses.
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Using this system, the research team collected and analyzed heart rate changes in Daphnia magna exposed to toxic substances at a high-throughput scale of approximately 150 individuals per hour. This large-scale analysis enabled the team to examine the distribution of individual responses, further improving analytical precision.
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By analyzing data distributions, the system can capture not only subtle differences among individuals but also sublethal toxic effects at low concentrations that are difficult to detect using conventional methods. Its intuitive and simple equipment design also makes it highly scalable, allowing flexible application across various research environments and test substances. The system is expected to be used in the future to assess the risks of chemicals and nanomaterials found in aquatic ecosystems such as rivers and lakes.
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This achievement is the result of joint research between KRISS and KIST Europe. The system, developed under the leadership of KRISS, was installed at KIST Europe, where researchers conducted nanomaterial toxicity assessment experiments and data validation using the platform.
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Dr. Kwon Ik Hwan, Senior Research Scientist at the Nanobio Measurement Group of KRISS, said, “This system enhances the precision of aquatic ecotoxicity assessment. We will continue to advance the technology so that it can be applied not only to nanomaterial toxicity assessment, but also to human-like models such as cardiac organoids.”
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Dr. Lee Tae Geol, Principal Research Scientist at KRISS, added, “The system developed by KRISS has been installed at a local laboratory of KIST Europe and is currently being used for CHIASMA, a Horizon Europe project. Going forward, we plan to expand its use among cardiotoxicity research teams around the world through technology transfer to Korean equipment developers.”
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