Nerve Guidance Conduit - Scaffold Material - Biological Polymers - Spider Silk Fiber

Spider Silk Fiber

Spider silk fibers are shown to promote cellular adhesion, proliferation, and vitality. Allmeling, Jokuszies et al. showed that Schwann cells attach quickly and firmly to the silk fibers, growing in a bipolar shape; proliferation and survival rates were normal on the silk fibers.

They used spider silk fibers to create a nerve conduit with Schwann cells and acellularized xenogenic veins. The Schwann cells formed columns along the silk fibers in a short amount of time, and the columns were similar to bands of Bungner that grow in vivo after PNS injury. Spider silk has not been used in tissue engineering until now because of the predatory nature of spiders and the low yield of silk from individual spiders. It has been discovered that the species Nephila clavipes produces silk that is less immunogenic than silkworm silk; it has a tensile strength of 4 x 109 N/m, which is six times the breaking strength of steel. Because spider silk is proteolytically degraded, there is not a shift in pH from the physiological pH during degradation. Other advantages of spider silk include its resistance to fungal and bacterial decomposiiton for weeks and the fact that it does not swell. Also, the silk's structure promotes cell adhesion and migration. However, silk harvest is still a tedious task and the exact composition varies among species and even among individuals of the same species depending on diet and environment. There have been attempts to synthetically manufacture spider silk. Further studies are needed to test the feasibility of using a spider silk nerve conduit in vitro and in vivo.