Inhibitory Effect of Hydrophilic Polymer Brushes on Surface‐Induced Platelet Activation and Adhesion

Abstract

Poly(N,N-dimethylacrylamide) (PDMA) brushes are successfully grown from unplasticized poly(vinyl chloride) (uPVC) by well-controlled surface-initiated atom transfer radical polymerization (SI-ATRP). Molecular weights of the grafted PDMA brushes vary from ≈ 35,000 to 2,170000 Da, while the graft density ranges from 0.08 to 1.13 chains · nm(-2). The polydispersity of the grafted PDMA brushes is controlled within 1.20 to 1.80. Platelet activation (expression of CD62) and adhesion studies reveal that the graft densities of the PDMA brushes play an important role in controlling interfacial properties. PDMA brushes with graft densities between 0.35 and 0.50 chains · nm(-2) induce a significantly reduced platelet activation compared to unmodified uPVC. Moreover, the surface adhesion of platelets on uPVC is significantly reduced by the densely grafted PDMA brushes. PDMA brushes that have high molecular weights lead to a relatively lower platelet activation compared to low-molecular-weight brushes. However, the graft density of the brush is more important than molecular weight in controlling platelet interactions with PVC. PDMA brushes do not produce any significant platelet consumption in platelet rich plasma. Up to a seven-fold decrease in the number of platelets adhered on high graft density brushes is observed compared to the bare PVC surface. Unlike the bare PVC, platelets do not form pseudopodes or change morphology on PDMA brush-coated surfaces.

Recent Progress in Surface Modification of Polyvinyl Chloride

“…Wet chemical means have been widely employed to alter the surface chemistry of PVC [76,77,78,79,80,81,82,83,84,85,86,87,88] due to the flexibility in terms of methodology and inexpensiveness. Nonetheless, they are risky to the living environment since hazardous chemicals are often needed as solvents, catalysts, etc.…”

“…More efficient modifications have been attained using controlled chemistry via precision mechanisms such as ATRP [84,85,86]. Zou et al [85,86] prepared poly(N,N-dimethylacrylamide) brushes on PVC sheets.…”

“…Zou et al [85,86] prepared poly(N,N-dimethylacrylamide) brushes on PVC sheets. To this end, primary amine groups were first introduced onto PVC surface by wet chemical modification with 4-ATP, followed by coupling of hydroxyl groups by a ring opening reaction of amine groups with glycidol.…”

Surface Modification of Polycarbonateurethane by Grafting Phosphorylcholine Glyceraldehydes for Improving Hemocompatibility

“…However, compared with the blank PCU, PCU-HDA and PCU-APEG films, platelets are rarely observed on the PCU-HDA-PCGA and PCU-APEG-PCGA films (Figure 3c and 3e), and the adhered platelets keep a round shape too. Although few platelets adhered to the surface of PC modified PCU films because of the heterogeneity of surface grafting, the results of the platelet adhesion experiment still reveal that PCU films grafted with phosphorylcholine shows high hemocompatibility [12]. …”

Engineering biomaterials surfaces to modulate the host response

“…Poly(N,N-dimethylacrylamide) (PDMA) based coatings were also used to build non-thrombotic surfaces [38,39]. Our group presented a comprehensive analysis of the interaction of PDMA brushes on model PS particles with plasma proteins and blood components [39].…”