Replacement Therapy to Tissue Engineering: The Shifting Paradigm

Biomaterials are the structural components of medical devices that interact with tissue.  Over most of the past century to current times, therapeutic medical devices have been used to replace structures or functions of the body.  Artificial hips, knees, intraocular lenses, even heart pacemakers are a few examples of replacement devices.   Although materials of construction have mostly been derived from commercial sources, materials specifically designed for medical devices are achieving increasing prominence.   As knowledge of the interactions of biomaterials with tissues has grown, device designers have learned to control the “host response” to provide improved device therapies.  While this control has led to improved replacement devices, notable examples of such devices being superseded by therapies that regenerate living tissue are demonstrable.  Some tissue regeneration processes include skin, cartilage, bone and nerve regeneration.  Tissue engineering involves the systematic control of the body’s cells, matrices and fluids.  It is of broad scope, encompassing the actions of many devices and processes used for medical therapy. This “prominence” argument is not universally embraced, but will be defended with examples of tissue engineering products in several therapeutic categories.  While biomaterials may be displaced, in part by tissue engineering, they will always be needed for replacement therapies and for delivering regenerative and other tissue engineering therapies.