Recently, researchers from the Institute of Intelligent Machines, Hefei Institutes of Physical Science, Chinese Academy of Sciences, including Wang Rujing and Chen Xiangyu, in collaboration with the research group led by Hong Yan from Anhui University of Science and Technology, have developed a novel capacitive-coupled non-contact conductivity detection microfluidic chip integrated with 3D microelectrodes, achieving rapid quantitative detection of a large number of nutrient ions in soil on-site. The relevant research results were recently published in "Computers and Electronics in Agriculture".
Abundant elements in soil such as nitrogen, phosphorus, and potassium play crucial roles in crop growth and agricultural production processes. Rapid and quantitative on-site detection of their content is of great significance for guiding precise fertilization. Traditional C4D microfluidic devices often suffer from insufficient sensitivity due to the configuration of planar sensing electrodes. However, 3D microelectrodes, by coupling with the microfluidic channel in a multi-faceted manner, increase the wall capacitance, enhance signal response, and have advantages such as low cost and simple fabrication.
The research team designed a novel capacitive-coupled non-contact conductivity detection microfluidic chip integrated with 3D microelectrodes, which includes a cross-shaped electrophoresis channel and a C4D microelectrode system composed of 3D channels manufactured integrally by microelectromechanical systems. The 3D microelectrode system consists of side wall electrodes and bottom electrodes, with the side wall electrodes realized by injecting liquid gallium indium into the electrode channel.
The developed novel microfluidic chip can detect the most important potassium ions, ammonium ions, nitrate ions, and phosphate ions in soil. Even when the concentrations of these ions are low, the new microfluidic chip demonstrates high sensitivity and good repeatability for multiple detections of the same soil sample. Overall, the performance of this device surpasses that of similar devices reported in literature.
The researchers explained that this research achievement introduces a novel and superior 3D microelectrode configuration scheme and low-cost fabrication process into C4D microfluidics. The integrated 3D microelectrode C4D microfluidic chip achieves stable, multi-index, and high-sensitivity on-site detection of a large number of nutrient ions in soil, effectively addressing the demand for rapid on-site testing of soil nutrients in farmland.
Related paper information: https://doi.org/10.1016/j.compag.2024.108829
