The device generates its own voltage from liquid flow, producing light signals to indicate contamination without needing an external power source. This breakthrough makes water quality testing more accessible, enabling real-time, portable monitoring in situations where traditional methods are impractical.
As pollution levels continue to rise, the demand for rapid water quality assessment has grown increasingly critical. Conventional monitoring systems typically depend on costly, bulky instruments that are difficult to operate, limiting their practicality in remote or resource-constrained settings.
The new self-powered device detects toxic amines in water. The technology generates light during a chemical reaction; the brightness of the light indicates the presence of pollutants, allowing for quick, on-the-spot detection of contamination.
The electrochemiluminescence (ECL) process depends on two main molecules: a chromophore, which acts as the light emitter, and a coreactant, which functions as the sacrificial species. Through redox reactions, these molecules excite the chromophore, which then releases light as it returns to its ground state—signaling the presence of the target compound.
Traditionally, ECL systems required an external power supply to drive these reactions. In contrast, the newly developed device operates without an external power source, instead harnessing the voltage generated by liquid flow through the system.
The project was headed by Professor Shinsuke Inagi of the Department of Chemical Science and Engineering at Science Tokyo, together with Dr. Elena Villani (at the time a specially appointed Assistant Professor) and Mr. Rintaro Suzuki (then a graduate student).
Since this ECL technique does not require a power supply, it opens new possibilities for applications such as pollutant detection in rivers or pipelines using natural flow energy. This concept can be extended for the ECL detection of a large pool of analytes, beyond environmental monitoring, such as for food and water testing, and biowarfare agents.
Shinsuke Inagi, Study Lead and Professor, Department of Chemical Science and Engineering, Institute of Science Tokyo
The researchers developed a microfluidic device consisting of two chambers with platinum wire electrodes, linked by a channel filled with porous material. Connected through an ammeter, the setup forms a split bipolar electrode system. When liquid is introduced into the channel—even by a simple hand-operated syringe—it generates a streaming potential of 2–3 volts, sufficient to drive redox reactions at the electrodes.
For the chromophore, benzothiadiazole-triphenylamine (BTD-TPA) was deposited on the anode, while tri-n-propylamine (TPrA) served as the coreactant. Amines were chosen as the target because they are common in industrial use and are recognized as toxic, carcinogenic, and mutagenic.
When a solution containing TPrA was introduced into the device, the streaming potential enabled oxidation of both the amine and the chromophore at the anode, setting off reactions that produced visible light. The resulting electroluminescence was intense enough to be recorded with a digital camera, with signals detectable at voltages as low as 2.3 volts.
Beyond TPrA, the system also identified other amines such as 2-(dibutylamino)ethanol and triethanolamine, though with lower sensitivity. It proved effective in detecting trace levels of amines in both distilled and tap water, achieving a detection limit down to 0.01 millimolar for TPrA. These results hold great promise, as the self-powered design allows real-time pollutant monitoring, which is particularly valuable in emergency situations where external electricity is not available.
We believe that our prototype may represent an innovative class of low-cost and portable analytical electrochemical devices that can be employed by using the electrical power of nature. Our vision for the future is that, once this technology has advanced and become more robust, a continuous natural water flow, for example, in a river, could be exploited to provide the necessary electrical energy to run the device.
Shinsuke Inagi, Study Lead and Professor, Department of Chemical Science and Engineering, Institute of Science Tokyo
Journal Reference:
Suzuki, R., et al. (2025) An electrochemiluminescence device powered by streaming potential for the detection of amines in flowing solution. Nature Communications. doi.org/10.1038/s41467-025-63548-2