Nanofiber reinforced alginate hydrogel for leak-proof delivery and higher stress loading in nucleus pulposus

Injectable hydrogels effectively remodel degenerative nucleus pulposus (NP) with a resemblance to the in vivo microenvironment. However, the pressure within the intervertebral disc requires load-bearing implants. The hydrogel must undergo a rapid phase transition upon injection to avoid leakage. In this study, an injectable sodium alginate hydrogel was reinforced with silk fibroin nanofibers with core-shell structures. The nanofiber-embedded hydrogel provided support to adjacent tissues and facilitated cell proliferation. Platelet-rich plasma (PRP) was incorporated into the core-shell nanofibers for sustained release and enhanced NP regeneration. The composite hydrogel exhibited excellent compressive strength and enabled leak-proof delivery of PRP. In rat intervertebral disc degeneration models, radiography and MRI signal intensities were significantly reduced after 8 weeks of injections with the nanofiber-reinforced hydrogel. The biomimetic fiber gel-like structure was con-structed in situ, providing mechanical support for NP repair, promoting the reconstruction of the tissue micro -environment, and finally realizing the regeneration of NP.

Automated summary

Injectable hydrogels reinforced with silk fibroin nanofibers were used to remodel degenerative nucleus pulposus. The composite hydrogel showed excellent compressive strength and leak-proof delivery, and the nanofibers provided support and facilitated cell proliferation. In a rat model, the nanofiber-reinforced hydrogel significantly reduced intervertebral disc degeneration.