Surface Modification of Nanofibers by Physical Adsorption of Fiber-Homologous Amphiphilic Copolymers and Nanofiber-Reinforced Hydrogels with Excellent Tissue Adhesion.

Herein, we report a simple approach to modify hydrophobic PCL nanofibers by adsorption of a fiber-homologous amphiphilic triblock copolymer (PCL-b-PEG-b-PCL, PCEC). The modified PCL nanofibers were then utilized to reinforce a physical hydrogel, which was formed by micellar crosslinking of the same PCEC triblock copolymer. Therefore, the copolymer played a dual role in not only dispersing and stabilizing nanofibers but also additionally providing a framework for the hydrogel matrix. The mechanical strength of the hydrogel was significantly enhanced by addition of the modified PCL nanofibers, and the gel modulus can be tuned by varying the concentration of the copolymer and nanofibers. The effect of nanofiber size and content on the mechanical properties of the hydrogel matrices was studied. Different from hydrogel composites that were reinforced by 2D fiber meshes or 3D woven fiber networks, this free fiber-reinforced hydrogel can be readily injected to adapt to the environmental shape and self-heal. The hydrogel composites showed superior tissue adhesion properties compared to the commercially available fibrin glue, especially in muscle adhesion. Due to its injectable and self-healing properties, this nanofiber-reinforced hydrogel may have great potential as a new type of tissue sealant.