Researchers demonstrate sensitive lead detection with wood-based microfluidic chips
About Optica
20 May 2025
Researchers demonstrate sensitive lead detection with wood-based microfluidic chips
New device offers sustainable, low-cost method for detecting lead in water
WASHINGTON — Researchers have developed a wood-based microfluidic chip that can detect lead in water using two different methods. The new chip could provide an economical and environmentally friendly way to monitor lead and other heavy metal pollution in water.
Caption: Researchers developed a wood-based microfluidic chip that can detect lead in water. Pictured is a version of the microfluidic chip used for the filtration test. The lower left image shows the solution before filtration and the lower right image, after filtration.
Credit: Yicheng Lyu, Shaanxi University of Science and Technology“Heavy metal pollution, especially lead pollution, poses a serious threat to the environment and human health,” said research team leader Chen Li from Shaanxi University of Science and Technology in China. “While traditional detection equipment is expensive and relies on toxic reagents, wood is inexpensive and biodegradable with built-in fluid-handling advantages. Our wood-based microfluidic chips demonstrate that renewable materials can be used for high-precision detection, which could lead to new advances in environmental monitoring technologies.”
In the Optica Publishing Group journal Applied Optics, the researchers describe their new chip, which uses both microwave and colorimetric spectroscopy to detect lead concentration in water. Their experimental results showed that the microfluidic chip is sensitive enough to allow early warnings of lead contamination and enable effective monitoring.
“In the future, portable wood chips could be used to quickly detect the water quality at home, avoiding the risk of lead poisoning,” said Yicheng Lyu, a member of the research team. “They could also be used by environmental protection departments to monitor pollution sources more efficiently or by factories to monitor the lead content of discharged water in real-time.”
Wood chips that work
Traditional biofluidic chips are typically made of plastics or glass, which are which are not readily accessible in nature and do not decompose easily. “Wood offers advantages such as low cost and natural microstructures that include both hydrophilic and hydrophobic regions, which can help control fluid flow,” said Li. “However, it has rarely been used in microfluidic chips before.”
Caption: The new chip uses both microwave and colorimetric spectroscopy to detect lead with high sensitivity.
Credit: Yicheng Lyu, Shaanxi University of Science and TechnologyTo find out if wood could be a good alternative for this application, the researchers fabricated microfluidic chips by using a laser to carve fluidic channels into the wood. These channels enabled functions such as filtration and chemical reactions. By carefully optimizing the laser parameters, such as power and engraving speed, they precisely carved the microchannels without charring or deforming the wood.
When water flows through the chip, lead ions from the water react with a chemical reagent in the microfluidic channel, causing a color change from yellow to pink that can be read by a camera or spectrometer. For microwave detection, the chip also has a miniature antenna circuit that exhibits a different signal when lead ions are attached.
Lead detection goes natural
To test the device, the researchers prepared lead solutions with concentrations ranging from 1 to 10,000 micrograms per liter. Using spectral color detection, the chip could detect lead concentrations as low as 1 microgram per liter. With microwave detection, the researchers observed that higher lead concentrations were linked with a more obvious change in the circuit signal, with a minimum detectable concentration of 10 micrograms per liter.
Caption: The chip is shown during testing with a spectrometer probe and light source for colormetric spectroscopic detection.
Credit: Hao Li, Shaanxi University of Science and Technology“Using both spectral and microwave detection allows us to make a preliminary judgment with the naked eye and also conduct precise measurements with instruments, ensuring the reliability of the results,” said Lyu. “The device is sensitive enough to, for example, confirm whether lead levels in drinking water are below the World Health Organization’s guideline of 10 micrograms per liter.”
Next, the researchers plan to expand the chip’s ability to detect more heavy metals in water, such as mercury and cadmium, make it more portable, and link it to a smartphone app for real-time analysis. They also aim to improve the device’s stability in wet environments and refine the manufacturing process to reduce costs and prepare for real-world water testing.
Paper: C. Li, Y. Lyu, H. Li, T. Zhao, S. Ding “Laser-Fabricated Wood-Based Microfluidic Chip
Integrating Dual Detection for Lead Ion Detection,” Appl. Opt, 64, 4447-4452 (2025).
DOI: 10.1364/AO.560953
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Optica Publishing Group is a division of the society, Optica, Advancing Optics and Photonics Worldwide. It publishes the largest collection of peer-reviewed and most-cited content in optics and photonics, including 18 prestigious journals, the society’s flagship member magazine, and papers and videos from more than 835 conferences. With over 400,000 journal articles, conference papers and videos to search, discover and access, our publications portfolio represents the full range of research in the field from around the globe.
About Applied Optics
Applied Optics publishes in-depth peer-reviewed content about applications-centered research in optics. These articles cover research in optical technology, photonics, lasers, information processing, sensing, and environmental optics. Optica Publishing Group publishes Applied Optics three times per month and oversees Editor-in-Chief Gisele Bennett, MEPSS LLC. For more information, visit Applied Optics.
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