Tissue Bionics

Tissue bionics: examples in biomimetic tissue engineering, by David W Green, published August 15, 2008 by IOP Publishing, available at http://www.iop.org/EJ/abstract/1748-605X/3/3/034010

Tissue bionics, a subfield of the diverse field of biomimetics, involves the use of naturally occurring substances to assist in replacing and regenerating damaged human tissue. There are two main areas of tissue bionics. The first modifies natural structures to make them compatible with the human body. The second uses these natural structures as inspiration and makes synthetic copies with similar properties. This article explains the advantages of biomimicry in the development of tissues and gives some examples of natural sources adapted for medical uses.

The use of naturally occurring materials as replacement tissue is generally the simpler approach to tissue bionics. An example of a material used is collagenous marine sponge tissue. The tissue is treated to remove all original proteins, leaving behind a scaffolding of collagen. Cells adhere to the porous surface provided by the many collagen fibers better than they adhere to synthetic materials. The sponge skeleton can also be coated with proteins which promote differentiation of pro-myoblast cells into bone cells. Studies done on rats at the University of Otago demonstrated that after a few weeks the sponge skeleton was accepted into the body more successfully than synthetic collagen scaffolding.

Green’s article also provides examples of successful synthetic technologies inspired by biological processes, such as polysaccharide capsules. These micro capsules are used to help facilitate tissue regeneration. They can be designed to include different materials depending on the components needed to regenerate a certain type of tissue. Components can even be separated within a capsule and released at different times. These polysaccharide capsules are made using a process which imitates biomineralization, the process living things use to make minerals.

Though the technology in the emerging field of tissue bionics is promising, it is still in the early stages of development. One concern with the replication of biomaterials is that their complexity makes them difficult to reproduce synthetically. This is not an issue when using manipulated natural materials, but it hinders the development of synthetic analogues. Another question is whether the implanted tissues will be as strong as the rest of the body’s tissue. Despite these concerns, developments in tissue bionics are exciting alternatives to older synthetic materials used to repair human tissue. By using and taking inspiration from natural materials, researchers are taking advantage of the successful designs developed by years of trial and error in nature.