Multi-CEM-embedded microfluidic system for simultaneous molecular enrichment and separation by multi-stage ion...

Area of Science:

• Analytical Chemistry
• Microfluidics
• Separation Science

Background:

• Ion concentration polarization (ICP) is effective for preconcentrating low-abundance particles.
• Traditional single-cation-exchange-membrane (CEM) microsystems face challenges in locational molecular separation based on mobility.
• Developing advanced ICP systems is crucial for efficient molecular separation and preconcentration.

Purpose of the Study:

• To develop a multi-CEM-embedded molecular enrichment and separation system utilizing the ICP effect.
• To investigate the mechanism of enrichment and separation within a multi-CEM system.
• To analyze the coupling effects between two cation-exchange membranes in the ICP process.

Main Methods:

• Fabrication of a multi-CEM microsystem integrated with the ICP effect.
• Experimental investigation of analyte enrichment and separation at distinct membrane interfaces.
• Systematic study of the influence of depletion effects on separation efficiency across multiple membranes.
• Demonstration using fluorescein sodium and sulforhodamine B as model analytes.

Main Results:

• Selective enrichment of fluorescein sodium and sulforhodamine B at distinct membrane interfaces was achieved.
• High enrichment factors of 5600 and 6200 were obtained for sodium fluorescein and sulforhodamine B, respectively.
• The depletion effect before the first CEM significantly impacts the efficiency of the second CEM.
• Intensified depletion at the second CEM showed minimal influence on the first CEM's performance.

Conclusions:

• The developed multi-CEM ICP system enables simultaneous enrichment and separation of multiple analytes.
• The study provides a theoretical framework for designing multi-stage ICP systems.
• This approach offers a novel strategy for preconcentrating and separating biomolecules like nucleic acids and proteins.