Tissue Engineering in the Future of Prosthetics

          Speaker Hongjun Wang gave a seminar on a biomedical approach toward functional tissue regeneration during a Chemisty and Biology seminar I took last spring. Achieving such a feat starts with creating an environment where cells can grow and prosper into a proper scaffold, or structure that supports the growth of cells into tissue.

          For the purpose of this seminar, Wang focused on the use of tissue engineering for the harvesting of cartilage, needed mostly for worn joints usually due to string from being overweight or being of old age. A biopsy is taken and put into a cell culture for the tissue to grow and be used for materials applicable to bone, skin, and muscle regeneration. That tissue can be implanted go through rehabilitation to heal and become a native structure within its surrounding environment. The Vacanti Mouse was shown as a prime example of this practice being put to the test. Using tissue engineering, cells harvested from a patient are seeded into a scaffold that is sculptured to look like an ear, where it is left in an incubator to later be attached to the mouse’s back. The mouse now has an ear constructed of pure, generic cartilage attached to its back. While the ear is not functional, it is a major sign of the future tissue engineering has in prosthetics. The use of generic regeneration is also widely applicable because it uses the patient's own cells as a basis of generating the tissue. Performing transplants in such a way deters rejection that is commonly seen in replantation. 

          The regeneration of skin is a little more complicated than that of cartilage due to its many layers and functionalities. The outer layers prevent bacterial invasion and hold in moisture to prevent dehydration while the inner layers contain hair follicles and other functional structures. Under those two layers lays the fat that does not need regeneration due to high availability. The top 2 layers are the ones that are important to grow and harvest. By cutting a square of skin from the back of a mouse and placing on that wound a skin graft, regeneration can take place and the skin will heal in place of the wound. Mimicking the high complexity of actual tissues poses as engineers’ biggest issue. High density and uniform cell seeding throughout the scaffold, maintaining cell viability and retaining tissue forming activities, incorporation of multiple cell types with appropriate spatial arrangement similar to native issue and creating a functional vascular network to supple nutrients and oxygen to the cell are a few of many functionalities that the skin can provide, but that scientists cannot reproduce.