- Replacement materials
- Material surface characteristics
- Tailoring immune system response
- Tissue engineering
Biocompatible materials are materials which are designed to exist and perform specific functions within living organisms. These include a broad range of substances such as structural metallic orthopedic prosthetic implants, artificial blood and skin, and surface coatings for implantable sensors for chronic (long-term) patient monitoring or electrodes for functional electrical stimulation.
While implant durability is one concern, the major problem is the body's ability to reject these materials as foreign objects either through an adverse immune system response or by attempting to "wall them off" by surrounding them with a protein layer. Newer porous materials for total joint replacement, by contrast, allow the existing bone to grow into the replacement joint. Structural orthopedic implants are primarily joint replacements for the hip or knee. While implants in less active elder patients were often structurally sufficient, the activity levels of younger patients caused premature device failure, often requiring multiple surgical replacement. Artificial blood and skin have great appeal by expanding a relatively limited resource and avoiding the problems of type matching and screening for bacterial or viral contamination. Chronic monitoring and functional electrical stimulation open the door to more effective low-dose therapies and functional restoration.
Biocompatible materials make a direct contribution to the improved health of the U.S. population by enabling a variety of biomedical applications. These materials and their adaptation are part of the growing biotechnology industry, contributing to job creation in that industry.
The importance of minimal anesthesia and proper tissue perfusion and oxygenation cannot be over emphasized, particularly in infants or geriatric patients. These materials are also important for the restorative care of battlefield casualties, and so contribute to reducing the damage from military operations.
The U.S. has a substantial leadership position in this area across metallic, ceramic, and organic materials with the possible exception of artificial blood where the Japanese have had a significant concentration of effort.