Plant-Inspired Flexible Wearable Sensor Enables Trace-Level Ethylene Gas Monitoring

Recently, the science and technology innovation team at Henan Agricultural University published an online research paper in “Nature Communications”, a Nature sub-journal, titled "A  Plant-receptor-inspired Cuprous Complex for Wearable Trace-level Ethylene Gas Sensing." Inspired by the ethylene recognition mechanism in plants, the research team developed a biomimetic ethylene sensing core unit and constructed a flexible wearable sensor based on it. This device requires no noble metal catalysis, achieves a low detection limit, and features fast response, high selectivity, and long-term stability, providing key technical support for trace-level ethylene gas monitoring in smart agriculture and the chemical industry.  

Ethylene (C₂H₄) is not only a key hormone regulating plant growth and development but also one of the most important basic raw materials in the global chemical industry. Real-time and accurate monitoring of ethylene gas is of great significance in scenarios such as post-harvest preservation of agricultural products, plant physiology research, and early warning of chemical pipeline leaks. However, traditional ethylene detection mostly relies on large-scale equipment like gas chromatographs, which suffer from drawbacks such as bulkiness, complex snition active site of the plant ethylene receptor, enabling specific capture of ethylene moample pretreatment, and difficulty in in-situ real-time monitoring. Existing commercial sensors also commonly face core bottlenecks, including reliance on noble metal catalysts like palladium and platinum, the need for high-temperature operating environments, insufficient selectivity, and difficulty in flexible integration—limitations that restrict their large-scale application in wearable and distributed monitoring scenarios.  

Ethylene receptors on the plant endoplasmic reticulum membrane, utilizing a Cu⁺ coordination center bridged by disulfide bonds, achieve specific recognition and signal transduction of trace ethylene in complex environments. This biological mechanism, shaped by long-term evolution, offers new inspiration for sensor design. Based on this, the team synthesized a cuprous ion complex (Cu₂Cyt) with a flower-like hierarchical structure via a one-step mild method. Its sulfur-bridged linkage and Cu⁺ coordination center effectively mimic the biological recoglecules through stable π-coordination with the C=C double bond of ethylene at room temperature without relying on noble metal catalysis.  

To achieve efficient signal transduction, the team combined Cu₂Cyt with the 2D semiconductor material MXene to construct a heterojunction sensing structure. Through multi-scale characterization and theoretical calculations, they systematically elucidated the cascaded electron transfer sensing mechanism: when ethylene molecules are specifically captured by the Cu⁺ active site, electrons are first transferred from the ethylene molecule to Cu₂Cyt, and then further transferred to the p-type semiconductor MXene substrate. This process reduces the hole carrier concentration in MXene, causing regular changes in electrode resistance, ultimately enabling accurate monitoring of ethylene gas concentration.  

The research team further integrated the sensing chip, testing circuit, communication module, and other components to build a wearable sensing system, which was validated in two core scenarios. In agricultural scenarios, the sensor can be directly attached to the surface of plants or fruits, continuously monitoring and revealing ethylene gas release patterns in situ, providing a non-invasive, real-time monitoring method for plant growth, post-harvest preservation of fruits and vegetables, and quality control in cold chain logistics. In industrial scenarios, the sensor can quickly respond to ethylene leaks from chemical pipelines, offering a low-cost solution for flexible, distributed industrial safety monitoring.  

Lu Lu Xu, a 2023 Ph.D. student in Agricultural Engineering at the College of Mechanical and Electrical Engineering, Henan Agricultural University, and Dr. Bohai Zhang from the College of Tobacco Science, are the co-first authors of the paper. Professors Junfeng Wu and Jiandong Hu, distinguished young talents at Henan Agricultural University, along with Professor Zhen Zhou from Zhengzhou University, are the co-corresponding authors. The research was supported by the Henan Provincial Science and Technology Research and Development Plan Joint Fund (No. 242103810027) and the Special Fund for Top-notch Talents at Henan Agricultural University.