Fabrication of stacked polymer cluster coatings via an evaporation-assisted grafting strategy for inducing...

The clustered polymer structures formed by grafting polymer brushes greatly enhance biomaterial surface properties. However, their nanoscale thickness and gaps caused by steric hindrance between clusters often lead to instability, limiting their applications. This study exploits the self-assembly of benzophenone-functionalized polymers into clusters in non-aqueous solvents, which are subsequently "frozen" and anchored to the surface through an evaporation-assisted grafting strategy to form stable, stacked polymer cluster coatings. This process is related to the rate of solvent removal and the proportion of benzophenone in the copolymer. This unique structure yields antifouling coatings with superior, sustained resistance to contaminants due to its closely stacked clusters. Moreover, this method can be extended to the preparation of stacked heparin-mimetic polymer cluster coatings that exhibit native binding of endothelial cell growth factors, inducing endothelial network formation, a capability not achievable with traditional methods. In vivo, the coating reduced inflammatory encapsulation and facilitated rapid endothelial organization and vessel-like remodeling at the implant-tissue interface. This strategy highlights the pivotal role of interfacial architectures and molecular interactions in guiding cellular behaviour, providing a distinct perspective on the development of high-performance coatings. STATEMENT OF SIGNIFICANCE: Our study introduces an evaporation-assisted grafting strategy to fabricate stacked polymer cluster coatings, overcoming the instability of traditional polymer brushes. These coatings demonstrate exceptional antifouling performance and support the versatile integration of functional components. Notably, the resulting stacked heparin-mimetic polymer coatings effectively induce endothelial network formation, rivalling commercial Matrigel-based assays. By harnessing precisely engineered interfacial structures and molecular interactions, this scalable, low-cost approach offers a solution for biomaterial surface design in tissue engineering applications.