Dual functionalization of poly(ε-caprolactone) film surface through supramolecular assembly with the aim of promoting in situ endothelial progenitor cell attachment on vascular grafts.

In this study, we developed a method for the dual functionalization of a poly(epsilon-caprolactone) (PCL) surface by means of the supramolecular assembly technology. Polyethylene glycol (PEG), with resistance to protein adsorption, and TPSLEQRT-VYAK (TPS) peptide, which can specifically bind endothelial progenitor cells (EPCs), were immobilized on the PCL surface through host-guest inclusion complexation. The chemical composition as well as the hydrophilic/hydrophobic property of the functionalized surface was characterized by X-ray photoelectron spectroscopy and water contact angle measurements. The relative composition of two functional molecules on the dually functionalized surface was further analyzed by fluorescence quantification. Finally, the fibrinogen adsorption, platelet adhesion and activation, and selective attachment of cells were systematically evaluated on the functionalized surface. The results show that the presence of PEG evidently inhibited the adsorption of plasma protein and platelet adhesion, thus reducing the possibility of thrombus formation on the functionalized surface. At the same time, the TPS-functionalized surface demonstrated enhanced attachment toward EPC compared with the surfaces in the absence of TPS functionalization. For the surface functionalized by both PEG and TPS, the functions provided by each component have been well demonstrated. The relative composition of the PEG and TPS could be further fine-tuned by adjusting the feeding ratio. All these results indicate that the dually functionalized surface developed in this study is a suitable candidate for vascular graft to induce and promote in situ endothelialization.