Microfluidic systems are being utilized increasingly in the analysis of biomolecules, especially nucleic acids. However, challenges associated with making high-performance capillary electrophoresis (CE) microchips have hindered the widespread application of these systems in bioanalysis. Although simple fabrication is feasible in materials like poly(dimethylsiloxane), the CE performance in this elastomer is less than ideal; on the other hand, glass CE microdevices provide high-quality separations, but microchip construction is more difficult. Hence, we have been developing new and straightforward strategies for making high-performance CE microdevices, to enhance bioanalysis. We recently demonstrated a phase-changing sacrificial layer technique that enables easy solvent bonding of polymer CE microchips.[1] In addition, this sacrificial layer method works for interfacing ionically conductive membranes with microchannels, to allow on-chip analyte preconcentration or electric field gradient focusing.[2] We also reported a thin-film sacrificial layer approach for fabricating glass CE microdevices, without the need for a thermal bonding step.[3] We have utilized the CE microchips, made using these simplified strategies, primarily in the analysis of amino acids, peptides and proteins; however, these CE microdevices also have excellent potential for application in the analysis of nucleic acids. Importantly, these advances in CE microchip fabrication using sacrificial layers should facilitate the rapid characterization of nucleic acids, proteins and peptides.  

References

[1]       Kelly, R.T.; Pan, T.; Woolley, A.T. Phase-Changing Sacrificial Materials for Solvent Bonding of High-Performance Polymeric Capillary Electrophoresis Microchips. Anal. Chem. 77, 3536-3541 (2005).

[2]       Kelly, R.T.; Li, Y.; Woolley, A.T. Phase-Changing Sacrificial Materials for Interfacing Microfluidics with Ion-Permeable Membranes to Create On-Chip Preconcentrators and Electric Field Gradient Focusing Microchips. Anal. Chem. 78, 2565-2570 (2006).

[3]       Peeni, B.A.; Conkey, D.B.; Barber, J.P.; Kelly, R.T.; Lee, M.L.; Woolley, A.T.; Hawkins, A.R. Planar Thin Film Device for Capillary Electrophoresis. Lab. Chip. 5, 501-505 (2005).