Such structures require very complex scaffolds filled with channels that would allow uid to ow and blood vessels to develop inside the tissue. Scientists at MIT are using a three-dimensional printing system to construct scaffolds a layer at a time, complete with a complex network of internal channels. Early results look promising structures seeded with liver endothelial cells and cultured for 5 weeks set up shop and not only looked like liver tissue but made albumin just like real liver. The method is being developed for cells of the periodontium and oral mucosa, but has application for virtually any tissue in the body. Injuries to the peripheral nervous system can result in partial or total paralysis of the affected tissues.
Nerve injuries can result from trauma, disease, and certain surgical procedures.
For example, surgery to remove tumors from the base of the skull often requires cutting through the facial nerve. Peripheral nerves can regenerate to a degree if the cut ends are surgically reconnected or joined by a nerve graft. However, current clinical treatments have led to incomplete recovery of motor and sensory function. Neural stem cells have been isolated from rat and mouse brains and have shown encouraging results for repairing damaged spinal cords. Even the brain itself shows promise for tissue regeneration.