Fabrication of ultrafast temperature‐responsive nanofibrous hydrogel with superelasticity and its 'on–off' switchable drug releasing capacity

Abstract The temperature‐responsive bulky hydrogel with fast response rate and satisfactory mechanical property has fascinating application potential in many aspects, such as the implantable macroscale controlled drug release carrier for post‐surgical therapy; however, creating such a smart hydrogel was proven extremely challenging. Here a novel type of temperature‐responsive bulky hydrogel with ultrafast response rate and super compressible elasticity was fabricated by the fibrous freeze‐shaping technique using shortened temperature‐responsive polymer based electrospun hollow nanofibers as building blocks, followed by heat treatment for endowing the hydrogel with high stability in water. Because the hydrogel has hierarchical porous structure and its constituent nanofibers have hollow structure, which are beneficial to diffusion of its embodied water during temperature‐induced volume phase transition, its temperature‐response time is less than 30 s. In addition, the hierarchical porous structure benefits dissipation of the compression stress exerted on the hydrogel. Fluorescein isothiocyanate (FITC)‐dextran as a model biomacromolecular drug, was loaded into the shells of the hollow nanofibers during coaxial electrospinning, and the ultimately obtained nanofibrous hydrogel can release its loaded FITC‐dextran in a 'on–off' switchable fashion in response to temperature alternation between 15 and 47°C. Cell cytotoxicity test results demonstrate that the temperature‐responsive nanofibrous hydrogel is biocompatible.