Reading Toxicity Through Daphnia Heartbeats... Detecting Even Low-Concentration Pollution [Reading Science]

KRISS Develops System Capable of Analyzing 150 Specimens per Hour

Significantly Enhances Precision of Environmental Safety Assessments

A technology capable of detecting "subtle toxicity signals" from environmental hazardous substances at an early stage has been developed. This method can identify low-concentration toxicity that conventional testing methods often miss.

The Korea Research Institute of Standards and Science (KRISS) announced on April 21 that it has developed a toxicity evaluation system that automatically measures and analyzes the heart rate of Daphnia. The system can simultaneously process data from up to 150 specimens per hour, significantly improving analytical precision compared to previous methods that relied on the average values of a small number of individuals.

This schematic diagram shows the process of fixing water fleas, measuring their heart rate with high-speed imaging, and analyzing the heart rate distribution of multiple specimens to evaluate toxic responses. The heart rate changes according to the concentration of copper oxide nanoparticles, demonstrating the ability to detect low-concentration toxicity that was difficult to identify with conventional testing methods. Provided by the research team

Daphnia, with their transparent bodies and high reproducibility, are widely used as representative organisms for aquatic environmental toxicity evaluation. However, the current internationally standardized test method, the Organisation for Economic Co-operation and Development (OECD) "Daphnia Acute Toxicity Test (202)," relies on visually determining swimming inhibition, which can lead to variations depending on the experimenter and has limitations in detecting low-concentration toxicity.

Overcoming the Limits of "Eyeball Toxicity"... Precision Measurement Using Heart Rate Data

Microscopic image of water flea used by KRISS for toxicity assessment research. Provided by the research team

The research team combined high-speed imaging and signal analysis technology to precisely measure the rapid heartbeats of Daphnia. The system captures the heart region of Daphnia immobilized on a fabric substrate, extracts repeated brightness changes, and automatically calculates heart rate.

This system can analyze heartbeats occurring 6 to 8 times per second in real time and immediately processes the measurement data to quantitatively assess toxic responses. In particular, by simultaneously analyzing the heart rate distributions of multiple individuals, it can capture even subtle differences in response among individuals.

In actual experiments, the research team successfully collected and analyzed large volumes of heart rate data in response to toxicant exposure, enabling the detection of low-concentration and sublethal toxic responses that are difficult to confirm using conventional methods.

Research team developing an environmental toxicity and nanomaterial toxicity assessment system based on the heart rate of multiple water fleas. From the front row clockwise: Senior Researcher Kiwhan Kwon of KRISS, Principal Researcher Taegul Lee, Principal Researcher Sangwon Lee. Provided by KRISS

The researchers expect this technology to be utilized in assessing the risks of chemicals and nanomaterials in aquatic ecosystems such as rivers and lakes. Its relatively simple equipment structure is also cited as a strength, allowing for application in diverse research environments.

Senior Researcher Kwon Ikhwan of the Korea Research Institute of Standards and Science commented, "This system is a technology that enhances the precision of aquatic environmental toxicity evaluations," adding, "We plan to expand its application to not only nanomaterials, but also to human-like models such as cardiac organoids in the future."

This research was conducted jointly by the Korea Research Institute of Standards and Science and the KIST Europe Research Institute, and the results have been published in the environmental journal Journal of Hazardous Materials. Utilization is expected to expand in areas such as responding to environmental regulations and evaluating nanomaterial safety.

This content was produced with the assistance of AI translation services.