Microfluidic paper-based biomolecule preconcentrator based on ion concentration polarization.

Area of Science:

• Analytical Chemistry
• Biomedical Engineering
• Materials Science

Background:

• Microfluidic paper-based analytical devices (μPADs) are promising for point-of-care diagnostics.
• Improving detection sensitivity in μPADs remains a critical challenge.
• Existing preconcentration methods for μPADs often involve complex fabrication.

Purpose of the Study:

• To develop a simple and effective paper-based preconcentrator for enhancing molecular detection sensitivity in μPADs.
• To utilize ion concentration polarization (ICP) for biomolecule preconcentration on a lateral-flow paper platform.
• To demonstrate the integration capabilities and performance of the novel preconcentrator.

Main Methods:

• Fabrication of a paper-based preconcentrator by patterning a cation selective membrane (Nafion) on adhesive tape and attaching it to paper channels.
• Application of an electric field across the Nafion membrane to induce ICP and preconcentrate biomolecules.
• Testing preconcentration performance using fluorescent dyes and proteins (FITC-albumin, bovine serum albumin) under steady lateral flow.

Main Results:

• Achieved high preconcentration performance up to 1000-fold for biomolecules.
• Maintained steady lateral fluid flow, enabling continuous delivery to the preconcentration zone.
• Demonstrated integration of the Nafion-patterned tape with various geometries (multiplexed preconcentrators) and platforms (string, polymer microfluidic channels).

Conclusions:

• The developed paper-based ICP preconcentrator offers a simple and effective solution for enhancing detection sensitivity in μPADs.
• This technology facilitates the integration of ICP devices with steady lateral flows in paper-based platforms.
• The approach holds potential for advancing point-of-care diagnostics and other microfluidic applications.