Elevating Postinjection Stability in Silk Nanofibril Hydrogels to Prevent Intervertebral Disc Degeneration

Injectable hydrogels offer a minimally invasive approach to treating intervertebral disc degeneration, a prevalent condition that affects 90% of individuals and often leads to significant pain and disability. Despite being a critical yet often overlooked issue that could lead to suboptimal therapeutic outcomes, the mechanical integrity of these gels frequently diminishes postinjection due to the injection process itself. To address this challenge, our research developed a silk-nanofibril-based hydrogel enhanced through simple <i>in situ</i> polymerization of dopamine. The resulting hydrogel not only effectively preserved its modulus at over 1000 Pa postinjection, matching the mechanical properties of the nucleus pulposus, but also significantly enhanced its antioxidative properties to four times that of the original silk nanofibril-based hydrogel. Furthermore, both cell-based and animal studies substantiated that such a silk nanofibril-based hydrogel integrated with polydopamine exhibited significant therapeutic efficacy in the injectable treatment of intervertebral disc degeneration. Therefore, this work introduced a new perspective on the design of injectable hydrogels that could effectively address both the mechanical and biochemical challenges of degenerative disc diseases, providing a platform for subsequent therapeutic interventions.