3D-printed solid-contact chloride sensor for sweat-based cystic fibrosis screening

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Materials Science

Background:

• Cystic fibrosis (CF) diagnosis relies on elevated sweat chloride levels.
• Current diagnostic methods can be invasive or require specialized equipment.
• There is a need for accessible and accurate sweat chloride monitoring.

Purpose of the Study:

• To develop and validate a 3D-printed chloride-selective ion-selective electrode (3Dp-Cl^--ISE) for sweat analysis.
• To enable accurate and reliable detection of chloride concentrations relevant to CF screening.
• To explore the potential of additive manufacturing for low-cost, point-of-care diagnostic devices.

Main Methods:

• Fabrication of a solvent-free, 3D-printed solid-contact chloride ISE using stereolithography (SLA).
• Integration of a photocurable selective membrane with a carbon-cloth transducer for efficient ion-to-electron transduction.
• Evaluation of sensor performance, including Nernstian response, selectivity against common sweat anions, and accuracy in human sweat samples.

Main Results:

• The 3Dp-Cl^--ISE demonstrated a Nernstian response (-55.3 mV/decade) across a physiologically relevant chloride concentration range (15.6–250 mM).
• The sensor exhibited minimal interference from bicarbonate and lactate, common sweat anions.
• Accurate quantification of spiked chloride concentrations in human sweat samples, including levels above 60 mM Cl^- relevant for CF screening.

Conclusions:

• The developed 3D-printed sensor is a durable, low-drift, and sweat-compatible platform for chloride sensing.
• Additive manufacturing enables customizable, low-cost, and scalable production of these sensors.
• The 3Dp-Cl^--ISE shows significant potential for point-of-care implementation and noninvasive monitoring of cystic fibrosis.