Highly Specific Binding on Antifouling Zwitterionic Polymer-Coated Microbeads as Measured by Flow Cytometry

Area of Science:

• Biomaterials Science
• Nanotechnology
• Surface Chemistry

Background:

• Micro- and nanoparticles are crucial in biomedical applications but suffer from biofouling due to nonspecific biomolecule adsorption.
• Biofouling leads to inaccurate diagnostic tests, causing false positives/negatives, particularly in clinical settings.
• Antifouling coatings are established for flat surfaces but underexplored for micro- and nanoparticles.

Purpose of the Study:

• To develop and demonstrate effective antifouling coatings for micro- and nanoparticles.
• To create magnetic beads with zwitterionic polymer brushes for enhanced biosensing performance.
• To enable specific molecular binding while minimizing nonspecific adsorption.

Main Methods:

• Preparation of magnetic micron-sized beads coated with zwitterionic sulfobetaine polymer brushes.
• Functionalization of coated beads with recognition elements (biotin and mannose moieties).
• Utilizing flow cytometry to assess specific binding and quantify nonspecific protein adsorption.

Main Results:

• The zwitterionic polymer brushes provided strong antifouling characteristics to the magnetic beads.
• Biotin-functionalized beads specifically bound streptavidin from serum protein mixtures.
• Mannose-functionalized beads specifically bound concanavalin A, demonstrating method versatility.
• Flow cytometry confirmed minimal nonspecific protein adsorption, showing high specificity.

Conclusions:

• Zwitterionic polymer-coated magnetic beads offer significant advancements for bead-based diagnostics and biosensing.
• These antifouling coatings address critical uncertainties caused by biofouling in experimental and clinical applications.
• The developed beads provide a robust platform for specific molecular capture under stringent antifouling conditions.