Characterization of Off-Stoichiometry Microfluidic Devices for Bioanalytical Applications

Area of Science:

• Polymer Chemistry
• Analytical Chemistry
• Bioanalytical Science

Background:

• Off-stoichiometry thiol-ene polymers (OSTE) are being explored for microfluidic devices.
• Microchip electrophoresis (MCE) requires robust and functional materials for efficient separation and detection.

Purpose of the Study:

• To investigate the properties of OSTE for microchip electrophoresis applications.
• To optimize OSTE formulations for improved performance in bioanalytical tasks.

Main Methods:

• Synthesized OSTE with varying allyl:thiol ratios (1.3:1 and 1:2.5).
• Evaluated polymer sealing, surface homogeneity (Raman imaging), and hydrophobicity (water contact angle).
• Measured electroosmotic flow (EOF) and demonstrated proof-of-concept bioanalytical applications.

Main Results:

• OSTE ratios of 1.3:1 and 1:2.5 exhibited superior sealing and surface homogeneity.
• Water contact angles were measured at 68° ± 6° and 71° ± 5°, indicating suitable surface properties.
• OSTE microchips showed a 1.5x higher EOF compared to polydimethylsiloxane (PDMS) and reduced sorption of nonpolar compounds.
• Successful immobilization of α-amylase and Saccharomyces cerevisiae cell counting were demonstrated.

Conclusions:

• Optimized OSTE formulations provide excellent material properties for MCE devices.
• The enhanced EOF and reduced analyte sorption make OSTE a competitive alternative to PDMS in bioanalysis.
• OSTE microchips are suitable for sensitive bioanalytical applications, including enzyme immobilization and cell counting.