Researchers have developed a wearable patch that detects plant stress early by monitoring hydrogen peroxide levels and transmitting real-time data to growers.
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Environmental conditions can put significant stress on plants, creating challenges for both home gardeners and large-scale farmers. Detecting this stress early—before visible signs like discoloration, wilting, or withering appear—is crucial for maintaining plant health.
Now, researchers reporting in ACS Sensors have developed a wearable patch that quickly identifies plant stress and sends real-time data to growers. This electrochemical sensor attaches directly to plant leaves and monitors hydrogen peroxide, a key distress signal.
Pests, drought, extreme temperatures, and infections all contribute to plant stress. When this happens, a plant's biochemistry shifts, leading to the production of hydrogen peroxide, which serves as both a distress marker and a signal for defense mechanisms. Detecting this early warning sign allows growers to take timely action, preventing further damage and optimizing crop yields.
However, most current detection methods involve removing plant tissue for analysis or using external detectors that rely on fluorescence—a process that can be complicated by chlorophyll interference.
Researchers have previously explored plant-wearable devices to monitor leaf water content as an indicator of plant health, but Liang Dong and his team sought to create a self-contained patch that directly and accurately measures hydrogen peroxide levels in living plants.
To develop this innovative patch, the researchers designed a flexible base covered with microscopic plastic needles, allowing it to adhere to the underside of leaves.
They then coated the surface with a chitosan-based hydrogel mixture that reacts to hydrogen peroxide, converting small chemical changes into measurable electrical signals. This mixture includes an enzyme that interacts with hydrogen peroxide to generate electrons, while reduced graphene oxide ensures efficient electron conduction through the sensor.
Testing the patch on live soybean and tobacco plants, the researchers found:
- When plants were infected with the bacterial pathogen Pseudomonas syringae pv. tomato DC3000, the sensor registered higher electrical currents in stressed leaves compared to healthy ones, with current levels correlating directly to hydrogen peroxide concentrations.
- The sensor’s readings were confirmed by conventional laboratory methods, demonstrating its accuracy.
- The patches detected hydrogen peroxide levels within one minute—significantly faster than previous needle-based sensors used on live plants.
- Each patch could be reused up to nine times before the microscopic needles began to degrade.
This technology could give growers a practical and cost-effective way to monitor plant health in real time.
We can achieve direct measurements in under a minute for less than a dollar per test. This breakthrough will significantly streamline analysis, making it practical for farmers to use our patch sensor for real-time disease crop monitoring.
Liang Dong, Department of Electrical and Computer Engineering, Iowa State University
Looking ahead, the researchers aim to refine the technology and improve its reusability. “Our next step is to refine the technology and enhance its reusability,” concludes Dong.
The study received funding from Iowa State University, the U.S. Department of Agriculture’s National Institute of Food and Agriculture, and the National Science Foundation.
Journal Reference:
Singh, N., et al. (2025). A Biohydrogel-Enabled Microneedle Sensor for In Situ Monitoring of Reactive Oxygen Species in Plants. ACS Sensors. doi.org/10.1021/acssensors.4c02645.