Multifunctional inverse opal film as a responsive drug carrier for spinal cord injury repair

An excellent drug delivery system is particularly important in trauma repair, especially for chronic hard-healing trauma, such as spinal cord injury (SCI). The SCI is difficult to repair as it is heavily influenced by inflammatory cell infiltration, neuronal axon rupture, and signal transmission interruption. Here, we present a stretched inverse opal film (SIOF) as a responsive drug carrier to deliver fibroblast growth factor 10 (FGF10) and chloroquine phosphate (CQ) for SCI repair. The SIOF was prepared by negatively replicating the silica nanospheres crystal array and was stretched to six times its original length. Benefiting from the elaborate interconnected nanopores of the SIOF, the temperature-sensitive hydrogel can host the black phosphorous quantum dots (BPQDs), and the two drugs (CQ and FGF 10) (Drugs-Gel@SIOF) for SCI repair. The excellent photothermal effect of BPQDs under the near-infrared (NIR) irradiation serves to regulate the release of drugs from the Drugs-Gel@SIOF. Furthermore, the SIOF has high biocompatibility and a special surface topology that orientates cell growth and promotes cytoskeleton elongation. The Drugs-Gel@SIOF showed an excellent effect of inhibiting inflammation and promoting axon growth. The practical performance of the Drugs-Gel@SIOF in promoting the recovery of motor function had been demonstrated by treating the spinal cord trauma rat model. These results indicate that this SIOF is an ideal intelligent delivery system with great potentials in nerve repair.