Porous Cellulose Substrate Study to Improve the Performance of Diffusion-Based Ionic Strength Sensors

Area of Science:

• Analytical Chemistry
• Materials Science
• Biotechnology

Background:

• Microfluidic paper-based analytical devices (µPADs) are crucial for low-cost, quantitative in-situ assays.
• Challenges remain in understanding cellulose-based membrane flow for accurate and rapid µPAD responses.
• Previous research often used commercial filter papers, facing limitations in test duration.

Purpose of the Study:

• To investigate the impact of diverse cellulose substrates on diffusion-based sensor performance.
• To correlate structural characteristics of cellulose fibers with sensor sensitivity and response time.
• To develop a rapid and sensitive µPAD for quantitative analysis in agri-food contexts.

Main Methods:

• Diffusion-based sensors were fabricated using laser cutting on various cellulose substrates (Whatman and lab-made Sisal papers).
• Structural properties including basis weight, density, pore size, fiber diameter, and length were analyzed.
• Sensor performance was evaluated based on sensitivity and response time.

Main Results:

• Cellulose substrates with larger pore sizes and lower basis weights demonstrated enhanced sensitivity and faster response times.
• The developed sensor successfully quantified ionic concentration in commercial wines with a limit of detection of 13.6 mM.
• The assay achieved a rapid response time of just 30 seconds.

Conclusions:

• Optimizing cellulose substrate characteristics is key to improving µPAD performance.
• The developed µPAD offers a promising tool for rapid, quantitative, and equipment-free assays in agri-food applications.
• This technology can empower non-experts in field-based quantitative analysis.