Microfluidic Sensor for Microplastic Detection in Saline Freshwater: Enhancements by Wheatstone Bridge and MXene-Coated Electrodes

This study presents a novel microfluidic sensor configuration that integrates a Wheatstone bridge and MXene-coated microwires to enhance the electrophoretic accumulation and detection of microplastics in freshwater with varying salinity. Compared to an equivalent setup lacking these enhancements, the proposed design achieves a three-fold improvement in sensor response. This advancement addresses a critical limitation of previous microplastic sensors, which typically exhibit reduced performance in high ionic strength environments. The Wheatstone bridge improves signal stability and precision by enabling the detection of minute resistance changes associated with microplastic accumulation. Simultaneously, the MXene coating increases particle capture efficiency by providing a high-surface-area electrode interface with strong affinity for microplastics. Together, these innovations enable sensitive, stable, and scalable detection of microplastics across a freshwater salinity range of 0–1000 ppm NaCl.