Antimicrobial resistance (AMR) is a growing global health crisis because of microbes, such as bacteria, becoming resistant to antibiotics. A leading factor in this rise is the improper use and disposal of antibiotics in the environment. Effluents from wastewater treatment plants often contain various antibiotics including trimethoprim (TMP), which can harm ecosystems by disrupting microbial communities essential for nutrient cycling. In addition to contributing to AMR, TMP poses various health risks to humans through indirect exposure.
Traditional methods for TMP detection such as capillary electrophoresis and liquid chromatography with mass spectrometry, are often labor-intensive and time-consuming. Electrochemical (EC) methods can provide respite from these issues by offering exceptional sensitivity, real-time analytical capabilities and the potential for miniaturization.
Professor Tae Yoon Lee and Dr. Natarajan Karikalan of Chungnam National University, Korea, have made a pioneering advancement in EC detection methods, that shows promise to revolutionize on-site testing for TMP in contaminated wastewater. They developed a disposable microfluidic lab-on-a-chip (LOC) EC sensor, μTMP-chip, designed for real-time TMP detection. “Efficient TMP monitoring in effluents is critical for effective control protocols. Hence, we aimed to enable in situ testing of water samples,” explains Prof. Lee. Their paper was made available online on September 21, 2024 and was published in Volume 499 of Chemical Engineering Journal on November 1, 2024.
The researchers designed the disposable chip by combining a special electrode made with lanthanum hydroxide and selenite, with a polyimide (PI) filter in a microfluidic channel. The analyses showed that the addition of selenite improved the electrode’s ability to detect chemicals by allowing better charge flow. Additionally, the PI filter improved the μTMP-chip’s real-time performance, while the efficiency dropped by 15 to 45% when the filter was removed. Additionally, the filter helped trap and isolate unwanted materials and prevented the risk of microbial growth, which could interfere with the sensor's function.
The μTMP-chip sensor demonstrated impressive results in real-world testing, showing recovery rates of 94.3 % to 97.6 % in soil and water samples. These results, obtained through wireless testing, highlight the chip’s potential for practical use in monitoring environmental samples.
“Our current design may face challenges in detecting TMP in highly polluted environments with significant matrix interferences. However, we hope our research will inspire further exploration into developing affordable and efficient TMP detection chips,” said Prof. Lee.
The researchers believe that their innovative lab-on-a-chip design has the potential to improve the feasibility of on-site, real-time tracking of environmental contaminants leading to improved conservation of ecosystems and human health.
