An Integrated Microfluidic SELEX Approach Using Combined Electrokinetic and Hydrodynamic Manipulation

Area of Science:

• Biotechnology
• Molecular Biology
• Microfluidics

Background:

• Systematic evolution of ligands by exponential enrichment (SELEX) is crucial for aptamer discovery.
• Traditional SELEX involves multiple offline steps, increasing complexity and time.
• Integrating SELEX steps on-chip offers a more efficient approach.

Purpose of the Study:

• To develop and demonstrate a microfluidic system for integrated, closed-loop aptamer selection.
• To simplify SELEX procedures by combining affinity selection and amplification on a single chip.
• To achieve rapid, high-affinity aptamer enrichment without offline manipulations.

Main Methods:

• A microfluidic device utilizing bead-based reactions for aptamer selection and amplification.
• Electrokinetic transfer for moving selected aptamers to amplification.
• Pressure-driven flow for transferring amplified aptamers back to selection.
• On-chip coupling of affinity selection and amplification for closed-loop enrichment.

Main Results:

• Demonstrated successful closed-loop, multiround aptamer enrichment on a microfluidic chip.
• Selected DNA aptamers against immunoglobulin E with high affinity (K_D = 12 nM).
• Achieved rapid aptamer selection in approximately 10 hours over 4 rounds.

Conclusions:

• The microfluidic approach effectively integrates SELEX, simplifying device operation and reducing processing time.
• This method enables efficient, on-chip aptamer discovery and enrichment.
• The developed system offers a rapid and streamlined platform for generating high-affinity aptamers.