A flexible wearable system for integrated sweat stimulation and chloride analysis in cystic fibrosis diagnosis

Cystic Fibrosis (CF) diagnosis relies on quantitative sweat chloride testing, a process that requires highly trained personnel, bulky instrumentation, and a cumbersome workflow performed at specialized clinical centers with high per-test cost. Recent advances in wearable sweat biomarker sensors offer opportunities for the development of point-of-care CF sweat chloride analysis. This work presents a flexible, wearable platform for sweat chloride testing, based on miniaturized, automated iontophoresis stimulation, microfluidic sweat collection, and colorimetric chloride analysis. This system enables quantitative, visually interpretable chloride measurements without external instrumentation, requires only microliters of sweat to operate, and reduces the per-test cost to around 1 dollar. Clinical evaluation of the device with 55 subjects at a single pediatric CF center demonstrates strong agreement between chloride concentrations from standard-of-care sweat testing and this platform, with reliable operation across physiologically relevant chloride concentrations. This platform provides a practical, scalable alternative for CF diagnosis in a range of clinical settings with potential for use in the home.