Thermochromic Hydrogel-Functionalized Textiles for Synchronous Visual Monitoring of On-Demand In Vitro Drug Release.

In vitro drug release systems have recently received tremendous attention because they allow noninvasive, convenient, and prolonged administration of pharmacological agents. On-demand epidermal drug release systems can improve treatment efficiency, prevent multidrug resistance, and minimize drug toxicity to healthy cells. In addition, real-time monitoring of drug content is also essential for guiding the determination of drug dosage and replacing drug carriers in time. Therefore, it is important to integrate the above properties in one ideal epidermal patch. Herein, photonic crystals (PCs) based on Fe3O4@C nanoparticles were introduced into drug-loaded poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-AAc)) hydrogel-functionalized textiles. Drug loading and release depended on the expansion and contraction of the hydrogels. The lower critical solution temperature (LCST) of the hydrogels was adjusted to 40 °C, which is higher than the skin temperature, by varying the content of hydrophilic comonomer acrylic acid (AAc) to store the drug at room temperature, and on-demand release was achieved by mild thermal stimulation. Moreover, the lattice spacing (d) of PCs varied with the expansion and contraction of the hydrogels, which can cause the color of P(NIPAM-AAc) hydrogel-functionalized textiles to change. These synchronous thermoresponsive chromic drug uptake and release behaviors provided an effective method for visual and real-time monitoring of drug content. Furthermore, in view of the poor mechanical properties of hydrogel wound dressings, textile matrices were composited to prevent holistic breaking during the stretching process. Biological experiments proved that the drug-loaded P(NIPAM-AAc) hydrogel-functionalized textiles had good antibacterial properties and wound-healing effects.