Poly(ethylene glycol)-functionalized polymeric microchips for capillary electrophoresis

Area of Science:

• Polymer Chemistry
• Analytical Chemistry
• Microfluidics

Background:

• Polymeric microchips for capillary electrophoresis (CE) often require surface modification to prevent protein adsorption.
• Poly(ethylene glycol) (PEG)-functionalized microchips were previously developed for intrinsic protein adsorption resistance.

Purpose of the Study:

• To investigate the impact of cross-linker purity and methyl methacrylate (MMA) comonomer on the performance of PEG-functionalized microchips in CE.
• To evaluate the optimized microchips for separating various analytes, including dyes, amino acids, peptides, and proteins.

Main Methods:

• Fabrication of PEG-functionalized polymeric microchips with varying cross-linker purity and MMA content.
• Capillary electrophoresis (CE) analysis of fluorescent dyes, amino acids, peptides, and proteins.
• Chiral separation using beta-cyclodextrin as a chiral selector.

Main Results:

• Impure poly(ethylene glycol) diacrylate (PEGDA) induced electroosmotic flow (EOF) and prolonged separation times.
• Addition of MMA significantly decreased separation efficiency (to ~25% of control).
• Optimized microchips achieved high CE efficiency (4.2 x 10^4 plates for aspartic acid) and demonstrated reproducible chiral separations (e.g., D,L-leucine with alpha=1.16, R(s)=1.64).

Conclusions:

• Cross-linker purity and comonomer selection are critical for optimizing PEG-functionalized microchip performance in CE.
• These microchips provide a robust platform for efficient and reproducible separation of diverse biomolecules and chiral compounds without surface modification.