A novel bubble rupture sensing methodology for sweat-driven disease diagnostics.

Area of Science:

• Biomedical Engineering
• Materials Science
• Physical Chemistry

Background:

• Sweat analysis offers a promising avenue for non-invasive disease diagnostics due to its rich biofluid composition.
• Current sweat diagnostic tools often require complex instrumentation, limiting their practical application.
• There is a need for simple, low-cost sensing technologies for sweat-based disease detection.

Purpose of the Study:

• To develop a novel, reagent-free bubble sensing methodology for analyzing electrolyte concentrations in sweat.
• To establish bubble rupture dynamics as a viable sensing mechanism for biosensor development.
• To correlate bubble film stability with electrolyte concentration for diagnostic purposes.

Main Methods:

• A reagent-free bubble sensing approach was developed using a sodium dodecyl sulphate-glycerol solution.
• Bubble stability was tested by introducing potassium chloride (KCl) solutions simulating varying sweat electrolyte concentrations.
• Bubble dynamics, including time to burst and film retraction time, were measured using visual observation and high-speed imaging.

Main Results:

• A strong exponential decay in bubble time to burst was observed with increasing KCl concentration (R² = 0.934).
• The sensing method showed high sensitivity within the healthy resting sweat electrolyte range (0.01-0.1 mol L⁻¹).
• High-speed imaging revealed distinct changes in bubble rupture and retraction dynamics correlated with ionic strength, with retraction time increasing significantly.

Conclusions:

• Bubble rupture dynamics can serve as a functional sensing mechanism for electrolyte concentration.
• This novel bubble sensing methodology provides a foundation for developing low-cost, simple surfactant bubble-based biosensors.
• The findings demonstrate the potential for a new class of non-invasive diagnostic tools leveraging fluid dynamics and surface chemistry.