Biomaterials requirements sterilizability

Implantation materials, which are in direct contact with blood, have to meet a particularly large range of requirements bio- and blood compatibility, mechanical strength against blood pressure, impermeability to the blood and its constituents, and sterilizability. In addition, the healing process that takes place on the inner and the outer surface of the artificial vessel is very different. The inner surface of the biomaterial should not stimulate adhesion of cellular blood components but should be covered with endothelial cells, whereas the outer surface of the prosthesis should be wrapped with connective tissue. 

Synthetic pol)mieric materials have been widely used in medical disposable supply, prosthetic materials, dental materials, implants, dressings, extracorporeal devices, encapsulants, polymeric drug delivery systems, tissue engineered products, and orthodoses as that of metal and ceramics substituents [Lee, 1989]. The main advantages of the polymeric biomaterials compared to metal or ceramic materials are ease of manufacturability to produce various shapes (latex, film, sheet, fibers, etc.), ease of secondary processability, reasonable cost, and availability with desired mechanical and physical properties. The required properties of polymeric biomaterials are similar to other biomaterials, that is, biocompatibility, sterilizability, adequate mechanical and physical properties, and manufacturability as given in Table 40.1. 

Materials intended for use inside the body have to be approved by regulatory agencies. The minimal requirements of biomaterials for medical applications include nontoxicity, effectiveness, and sterilizability (Table 27.1). Although many currently available biomaterials meet these requirements, most of them lack biocompatibility. 

It is important to pay attention to the distinction between nontoxicity and biocompatibility in Table 2. Nontoxicity means biologically safe, that is, inflammation, both chronic and acute, bleeding, allergic responses and diseases like cancer are not caused or triggered by the biomaterial. This property is a minimum requirement for any biomaterial. Without satisfying this requirement, as well as the requirement that the material be sterilizable, it is not possible to obtain permission from the Minisliy of Health in Japan. At this time, the toxicity of a material is due mainly to the soluble compounds found in the material or microbes that adsorb onto the... 

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