Cross-Linker-Based Design of Selective Macroporous Polymer Resins for Uremic Toxin Removal

Area of Science:

• Materials Science
• Biomedical Engineering
• Chemical Engineering

Background:

• Uremic toxins threaten kidney dialysis patients' health and longevity.
• Current adsorption strategies face challenges due to the diverse properties of uremic toxins.
• Developing selective adsorbent materials is crucial for enhancing dialysis efficacy.

Purpose of the Study:

• To synthesize and investigate macroporous polymer resins (MPRs) with varying chemical functionalities.
• To understand how cross-linker molecular structure impacts uremic toxin adsorption.
• To evaluate MPR performance for selective capture of beta2-microglobulin (B2M) and urea.

Main Methods:

• Bulk polymerization was used to synthesize MPRs with five different multifunctional monomers (cross-linkers).
• Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) confirmed network formation.
• Scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) porosimetry characterized resin morphology and surface area.
• Adsorption studies were conducted using beta2-microglobulin (B2M) and urea in dialysis fluid and aqueous solutions.

Main Results:

• MPRs exhibited diverse morphologies and surface areas (183–975 m²/g).
• The ethylene glycol dimethacrylate (EGDMA)-based MPR showed exceptional B2M adsorption (2837 μg/g), 20 times higher than activated carbon.
• This enhanced B2M capture was attributed to amphiphilic chemistry and optimized hierarchical pore architecture.
• Urea adsorption was negligible across all MPRs, with activated carbon showing superior performance for urea removal.

Conclusions:

• Cross-linker selection significantly influences the adsorption selectivity of MPRs.
• The EGDMA-based MPR demonstrates potential for selective capture of larger uremic toxins like B2M.
• These findings provide a foundation for designing tailored adsorbent materials for improved dialysis applications.