Promotion of peripheral nerve regeneration of a peptide compound hydrogel scaffold

Abstract

Background: Peripheral nerve injury is a common trauma, but presents a significant challenge to the clinic. Silk-based materials have recently become an important biomaterial for tissue engineering applications due to silk's biocompatibility and impressive mechanical and degradative properties. In the present study, a silk fibroin peptide (SF16) was designed and used as a component of the hydrogel scaffold for the repair of peripheral nerve injury. Methods: The SF16 peptide's structure was characterized using spectrophotometry and atomic force microscopy, and the SF16 hydrogel was analyzed using scanning electron microscopy. The effects of the SF16 hydrogel on the viability and growth of live cells was first assessed in vitro, on PC12 cells. The in vivo test model involved the repair of a nerve gap with tubular nerve guides, through which it was possible to identify if the SF16 hydrogel would have the potential to enhance nerve regeneration. In this model physiological saline was set as the negative control, and collagen as the positive control. Walking track analysis and electrophysiological methods were used to evaluate the functional recovery of the nerve at 4 and 8 weeks after surgery. Results: Analysis of the SF16 peptide's characteristics indicated that it consisted of a welldefined secondary structure and exhibited self-assembly. Results of scanning electron microscopy showed that the peptide based hydrogel may represent a porous scaffold that is viable for repair of peripheral nerve injury. Analysis of cell culture also supported that the hydrogel was an effective matrix to maintain the viability, morphology and proliferation of PC12 cells. Electrophysiology demonstrated that the use of the hydrogel scaffold (SF16 or collagen) resulted in a significant improvement in amplitude recovery in the in vivo model compared to physiological saline. Moreover, nerve cells in the SF16 hydrogel group displayed greater axon density, larger average axon diameter and thicker myelin compared to those of the group that received physiological saline. Conclusion: The SF16 hydrogel scaffold may promote excellent axonal regeneration and functional recovery after peripheral nerve injury, and the SF16 peptide may be a candidate for nerve tissue engineering applications.

Effects of Recombinant Spidroin rS1/9 on Brain Neural Progenitors After Photothrombosis-Induced Ischemia

“…The efficiency of using structural silk proteins from B. mori and N. clavipes for creating a matrix for neural tissue engineering has been demonstrated in numerous studies (Magaz et al, 2018;Salehi et al, 2020). Biomaterials based on silkworm fibroin are able to maintain the adhesion of neurons without adversely affecting their proliferation, morphology, and migration (Qu et al, 2010;Wei et al, 2013). In addition, fibroin scaffolds not only can support the adhesion and viability of cortical neurons but also carry a neuroprotective role demonstrated in the oxygen-glucose deprivation model (Moisenovich et al, 2019).…”

Self-Assembling Peptides- Notion and Medical Applications: A Review

“…Nanofibrous scaffolds have been extensively used in neural tissue engineering applications due to their similarity to the extracellular matrix and high surface area to volume ratio. For nanofiber production, the most widely used techniques are Electrospinning and selfassembly for their neural applications 30 .…”

Recombinant Spider Silk and Collagen-Based Nerve Guidance Conduits Support Neuronal Cell Differentiation and Functionality in Vitro

“…The biomaterials for peripheral nerve repair tested thus far include collagen, − polycaprolactone, , polyglycolic acid and polylactic acid, chitosan, , alginate, spider silk, , silkworm fibroin, − and other composites or derivatives made thereof. , Of particular interest is spider silk and collagen and combining them allows for the fabrication of materials with tailored biological activity and mechanical stability . Spider silk is well-known for its good mechanical properties , and does not contain the sometimes problematic sericin as associated with silkworm silk. , Moreover, spider silk has been demonstrated to be suitable for peripheral nerve repair: natural spider silk placed in isogenic veins enabled the generation of nerve grafts bridging a 2 cm gap injury in the sciatic nerve of rats .…”