POLYZWITTERIONIC COATING OF POROUS ADSORBENTS FOR THERAPEUTIC APHERESIS

• Published in: International journal of artificial organs Vol. 46; no. 7; p. 427
• Main Authors: Semak, V, Eichhorn, T, Weiss, R, Weber, V
• Format: Journal Article
• Language: English
• Published: Milan Wichtig Editore s.r.l 01-07-2023
• Subjects: Acrylic resins; Adsorbents; Adsorption; Antithrombin; Apheresis; Beads; Blood; Cell adhesion; Coagulation; Coating effects; Coatings; Compatibility; Divinylbenzene; Fluorescence; Fluorescence microscopy; Free radical polymerization; Hemolysis; Hydrophilicity; Hydrophobicity; Interleukin 6; Irradiation; Leukocytes (neutrophilic); Monomers; Parameters; Polyacrylamide; Polyacrylate; Polymers; Polystyrene; Polystyrene resins; Protein C; Proteins; Prothrombin; Surface chemistry; Synthesis; Terpolymers; Thromboplastin; Tumor necrosis factor-α; Ultraviolet radiation; Zwitterions
• ISSN: 0391-3988; 1724-6040

Methods: We developed blood-compatible matrices by surface modification with polyzwitterionic polysulfobetainic and polycarboxybetainic coatings. Photoreactive zwitterionic terpolymers were synthesized by free-radical polymerization of zwitterionic, photoreactive and fluorescent monomers. Upon UV irradiation, the terpolymers were photo-deposited and mutually crosslinked on the surface of hydrophobic polystyrene-co-divinylbenzene (CG161c, Amberchrom) and hydrophilic polyacrylamide-co-polyacrylate (DALI, Fresenius Medical Care) beads. Blood compatibility was evaluated by assessing polymer-induced hemolysis, coagulation parameters, and cell adhesion to the material surface under batch and flow conditions. The remaining adsorption capacity of coated adsorbents was studied in human whole blood. Results: Fluorescence microscopy revealed coatings with an average thickness of 5 µm, which were limited to the bead surface. The plain synthesized polyzwitterions (1.0 mg/mL), as well as coated adsorbents (10% v/v), did not induce hemolysis (Hb <5 mg/dL). Polyzwitterionic coating of the hydrophobic CG161c adsorbents improved coagulation parameters by significantly shortening prothrombin time (PT), activated partial thromboplastin time (aPTT), and diminishing the adsorption of antithrombin (AT)-III and protein C. In the case of DALI, the coating effect was less pronounced. Coated CG161c maintained an adsorption capacity of 39-67% for IL-6 and 25-35% for TNF-α, while the coated DALI beads preserved 80% of the adsorption capacity for low-density lipoprotein. Conclusions: Coating enhanced the blood compatibility of hydrophobic, but not of hydrophilic adsorbents. The most pronounced effect was observed on coagulation parameters (PT, aPTT, AT-III, protein C) and neutrophil count. Polycarboxybetaine with a charge spacer of 5 carbons was the most promising polyzwitterion for the coating of adsorbents for whole blood apheresis.