A new fabrication technique to form complex polymethylmethacrylate microchannel for bioseparation

Area of Science:

• Microfluidics
• Bioseparations
• Analytical Chemistry

Background:

• Reduction in cross-sectional area improves concentration factors in microscale bioseparations.
• Step reductions in microchips cause band dispersion and distortion.
• Gradual reductions offer a potential solution to mitigate these issues.

Purpose of the Study:

• To develop a novel fabrication technique for gradual cross-sectional area reductions in polymethylmethacrylate (PMMA) microchannels.
• To enable high-fidelity fabrication of both 1D and 2D gradual reduction microchannels.
• To evaluate the performance of these microchannels in isotachophoresis (ITP) for preconcentration.

Main Methods:

• Fabrication using hot embossing and surface modification assisted bonding.
• Creation of gradual, one-dimensional (1D) and two-dimensional (2D) cross-sectional area reductions.
• Application in anionic and cationic isotachophoresis (ITP) for fluorescent protein separation and preconcentration.

Main Results:

• Successfully fabricated PMMA microchannels with gradual cross-sectional area reductions with high fidelity.
• Achieved significant preconcentration of fluorescent proteins using the developed microchannels.
• Obtained thousand-fold and ten-thousand-fold concentration increases with 10x and 100x gradual reductions, respectively.

Conclusions:

• The novel fabrication technique effectively creates gradual cross-sectional area reductions in PMMA microchannels.
• Gradual reductions significantly enhance concentration factors in isotachophoresis (ITP) compared to step reductions.
• This method offers a promising approach for advanced microscale bioseparation and preconcentration applications.