A modular potentiometric sensor platform with detachable microfluidics for multiplexed analysis of low-volume biofluids.

Simultaneous detection of ionic biomarkers in human biofluids such as sweat, saliva, and blood is of great significance for disease screening, exercise physiology monitoring, and personalized health management. However, current analytical methods are often constrained by fixed functionality, limited scalability, and high sample consumption. Inspired by traditional Chinese movable-type printing, this study proposes a modular potentiometric sensing platform integrating detachable microfluidics. The platform allows flexible configuration and replacement of sensing modules according to specific analytical requirements while reducing sample consumption to microliter levels. A representative microfluidic platform incorporating four sensing modules was constructed for the detection of pH, K+, Na+, and Ca2+ in biofluids. This platform enables simultaneous detection of all four analytes within approximately 20 min, requiring only about 380 µL of total sample per test. Each sensing module exhibited a near-Nernstian response across the tested concentration ranges, along with excellent linearity and reproducibility. Validation using simulated sweat further demonstrates the platform’s analytical reliability and practical applicability. This modular sensing strategy provides a customizable and efficient solution for rapid on-site biochemical analysis of biofluids with minimum analyte consumption.