Biomaterial

Hip joint replacement, United States, 1998 Wellcome L0060175

Atomic structure of Lithium-7

CNX Chem 10 06 UnitCell1

Biomaterials are substances that have been engineered to interact with biological systems for a medical purpose - either a therapeutic (treat, augment, repair, or replace a tissue function of the body) or a diagnostic one. As a science, biomaterials is about fifty years old. The study of biomaterials is called biomaterials science or biomaterials engineering. It incorporates elements of medicine, biology, chemistry, tissue engineering, and materials science.

Overview

Biomaterials can be derived from nature or synthesized in the laboratory using a variety of chemical approaches utilizing metallic components, polymers, ceramics or composite materials. They are often used and/or adapted for a medical application, and thus comprise whole or part of a living structure or biomedical device which performs, augments, or replaces a natural function. Such functions may be benign, like being used for a heart valve, or may be bioactive with a more interactive functionality such as hydroxyapatite coated hip implants. Biomaterials are also used every day in dental applications, surgery, and drug delivery. For example, a construct with impregnated pharmaceutical products can be placed into the body, which permits the prolonged release of a drug over an extended period of time. A biomaterial may also be an autograft, allograft or xenograft used as a transplant material.

Classification

Biomaterials are commonly classified by their origin or their material properties.

By Origin

• Natural Biomaterials: These are derived from natural sources, living organisms, or their by-products, such as collagen, chitosan, and alginate. They are often used for tissue engineering and regenerative medicine.
• Synthetic Biomaterials: These are man-made materials created in the laboratory, including polymers (e.g., polyethylene, polylactic acid), ceramics (e.g., alumina, zirconia), and metals (e.g., titanium, stainless steel).

By Material Properties

• Metals: Known for their strength and durability. Used in load-bearing applications such as joint replacements and dental implants.
• Ceramics: Biocompatible and very hard, but brittle. Used for bone grafting and in some dental applications.
• Polymers: Flexible and can be designed to degrade over time. Used in a variety of applications including sutures, drug delivery systems, and tissue engineering scaffolds.
• Composites: Combine two or more different materials to achieve desired properties. Used in a variety of applications, including dental and bone repair materials.

Applications

Biomaterials are used in:

• Tissue engineering to create artificial organs and regenerate damaged tissues.
• Medical devices such as heart valves, hip replacements, and dental implants.
• Drug delivery systems for the controlled release of drugs.
• Wound healing products like sutures and staples for tissue repair.

Challenges and Future Directions

The field of biomaterials faces several challenges, including the need for improved biocompatibility, the reduction of adverse reactions, and the development of more sophisticated materials that can mimic the complexity of natural tissue structures. Future directions may include the development of smart biomaterials that can respond to biological signals, self-healing materials, and further integration of biomaterials with tissue engineering and regenerative medicine to create more complex, functional tissues and organs.