Surface-Independent Hierarchical Coatings with Superamphiphobic Properties

Facile approaches for the fabrication of substrate independent superamphiphobic surfaces that can repel both water and organic liquids have been limited. The design of such super-repellent surfaces is still a major challenge of surface chemistry and physics. Herein, we describe a simple and efficient dip-coating approach for the fabrication of highly hierarchical surface coatings with superamphiphobic properties for a broad range of materials based on a mussel-inspired dendritic polymer (MI-dPG). The MI-dPG coating process provides a precise roughness control, and the construction of highly hierarchical structures was achieved either directly by pH-controlled aggregation or in combination with nanoparticles (NP). Moreover, the fabrication of coatings with a thickness and roughness gradient was possible via simple adjustment of the depth of the coating solution. Subsequent postmodification of these highly hierarchical structures with fluorinated molecules yielded a surface with superamphiphobic properties that successfully prevented the wetting of liquids with a low surface tension down to about 30 mN/m. The generated superamphiphobic coatings exhibit impressive repellency to water, surfactant containing solutions, and biological liquids, such as human serum, and are flexible on soft substrates

Selective Endothelial Cell Adhesion via Mussel-Inspired Hybrid Microfibrous Scaffold

Endothelialization of the polymer substrate is limited by unspecific cell adhesion. Herein, a biodegradable microfibrous scaffold with a reversibly thermoswitchable property was developed to dynamically regulate endothelial progenitor cell adhesion by exposing or concealing cRGD motif to the surface with a thermosensitive moiety (cRGD-PNIPAM) and antifouling moiety linear polyglycerol (LPG). Owing to a reversible α_vβ₃ integrin–cRGD interaction and ligand presentation, the accelerated endothelial cell adhesion and spreading were achieved. Under the static and dynamic conditions, prestained endothelial cells were quickly attached to the surface at 25 °C via the integrin–cRGD interaction, and the cRGD was the headgroup of the stretched PNIPAM below the LCST of PNIPAM. With the increase of the temperature to 37 °C, a quick detachment of cells from the surface was observed due to the cRGD moiety being shielded by the antifouling LPG layer. As compared to current strategies for endothelialization, for example, loaded drugs or growth factors, such a tunable dynamic system based on “switchable surfaces” may unlock new application in in situ targeted cell recruitment and might become useful in regenerative medicine

High-Antifouling Polymer Brush Coatings on Nonpolar Surfaces via Adsorption-Cross-Linking Strategy

A new “adsorption-cross-linking” technology is presented to generate a highly dense polymer brush coating on various nonpolar substrates, including the most inert and low-energy surfaces of poly­(dimethylsiloxane) and poly­(tetrafluoroethylene). This prospective surface modification strategy is based on a tailored bifunctional amphiphilic block copolymer with benzophenone units as the hydrophobic anchor/chemical cross-linker and terminal azide groups for in situ postmodification. The resulting polymer brushes exhibited long-term and ultralow protein adsorption and cell adhesion benefiting from the high density and high hydration ability of polyglycerol blocks. The presented antifouling brushes provided a highly stable and robust bioinert background for biospecific adsorption of desired proteins and bacteria after secondary modification with bioactive ligands, e.g., mannose for selective ConA and Escherichia coli binding