Biomaterial

The development of biomaterials is not a new area of science, having existed for around half a century. The study of biomaterials is called biomaterial science. It is a provocative field of science, having experienced steady and strong growth over its history, with many companies investing large amounts of money into the development of new products. Biomaterial science encompasses elements of medicine, biology, chemistry, tissue engineering and materials science.

Definition

While a definition for the term 'biomaterial' has been difficult to formulate, more widely accepted working definitions include:

"A biomaterial is any material, natural or man-made, that comprises whole or part of a living structure or biomedical device which performs, auguments, or replaces a natural function".

" A Biomaterial is a nonviable material used in medical device,so its intended to interact with a biological systems (William 1987)"

A biomaterial is essentially a material that is used and adapted for a medical application. Biomaterials can have a benign function, such as being used for a heart valve, or may be bioactive and used for a more interactive purpose such as hydroxy-apatite coated hip implants (the Furlong Hip, by Joint Replacement Instrumentation Ltd, Sheffield is one such example – such implants are lasting upwards of twenty years). Biomaterials are also used every day in dental applications, surgery, and drug delivery (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).

The definition of a biomaterial does not just include man-made materials which are constructed of metals or ceramics. A biomaterial may also be an autograft, allograft or xenograft used as a transplant material.

Applications

Biomaterials are used in:

* Joint replacements
* Bone plates
* Bone cement
* Artificial ligaments and tendons
* Dental implants for tooth fixation
* Blood vessel prostheses
* Heart valves
* Skin repair devices
* Cochlear replacements
* Contact lenses

Biomaterials must be compatible with the body, and there are often issues of biocompatibility which must be resolved before a product can be placed on the market and used in a clinical setting. Because of this, biomaterials are usually subjected to the same requirements of those suffered by new drug therapies. All manufacturing companies are also required to ensure traceability of all of their products so that if a defective product is discovered, others in the same batch may be traced.

Subjects integral to biomaterials science

* Toxicology

A material should not be toxic, unless specifically engineered to be so (for example “smart” drug delivery systems that target cancer cells and destroy them).

* Biocompatibility

Biocompatibility is difficult to measure, it is defined in terms of success at a specific task.

* Functional Tissue structure and pathobiology

Understanding of the anatomy and physiology of the action site is essential for a biomaterial to be effective.

* Healing

Healing is an essential consideration when using biomaterials. The body may experience what is known as a foreign-body reaction after implementation so immuno-suppression may be required.

* Dependence on Specific anatomical sites of implantation

It is important, during design, to ensure that the implement will fit complementarily and have a beneficial effect with the specific anatomical area of action.

* Mechanical and Performance requirements

Biomaterials that have a mechanical operation must perform to certain standards and be able to cope with pressures. It is therefore essential that all biomaterials are well designed and are tested. Biomaterials that are used with a mechanical application, such as hip implants, are usually designed using CAD (Computer Aided Design) which allows all of the directional stresses to be calculated, ensuring maximum product life.

* Industrial involvement

Companies and researchers push the boundaries and development of science in general, and biomaterials are no exception.

* Ethics

Ethical considerations are paramount – as are legal considerations and compliance with the law.

* Regulation

As mentioned above, regulation and records are required to be kept by the product manufacturer for much longer than the product life.