Microscale isoelectric fractionation using photopolymerized membranes

Area of Science:

• Biochemistry
• Analytical Chemistry
• Microfluidics

Background:

• Proteomics research requires efficient methods for isolating specific molecules from complex biological samples.
• Existing techniques often face challenges with throughput, sensitivity, and integration into microfluidic systems.

Purpose of the Study:

• To introduce and validate microscale isoelectric fractionation (μIF) for on-chip isolation and enrichment of molecular species.
• To demonstrate the customizable fabrication and versatile application of μIF in microfluidic devices.

Main Methods:

• Photopatterning of narrow pH-specific polyacrylamide membranes in situ within microfluidic channels.
• Electrophoretic separation of charged species based on their isoelectric points (pI) without carrier ampholytes.
• Development of single and serial membrane fractionator designs for diverse applications.

Main Results:

• Efficient and reproducible fractionation of fluorescent pI markers and proteins from buffer and cell lysate.
• Successful isolation of target analytes from high-abundance serum components using a 3-membrane μIF system.
• Demonstrated rapid and non-dispersive transfer of focused proteins between chip locations.

Conclusions:

• Microscale isoelectric fractionation (μIF) offers a rapid, versatile platform for integrated sample preparation and multidimensional analysis.
• μIF addresses the critical need for isolating trace analytes from complex biological matrices in microfluidic formats.
• The technology facilitates precise molecular enrichment and compartmentalization for downstream analytical or preparative operations.