Biomaterials requirements

The in vitro study of the hemocompatibility of biomaterials requires the consideration of many parameters, static or dynamic contact, flow rate, wall shear rate, form of biomaterial to be tested, pathway to consider (platelet adhesion, platelet activation, complement activation, contact phase activation etc..) and duration of contact(39). It has previously been demonstrated t t hemodynamic circumstances play a significant role in determining localization, growth and fiagmentation of thrombi and platelet adhesion in vivo, and that flow rate controls platelet transport to a surface and their adhesion (40). This evidence is siqtpoited by observed differences in platelet activity predominance in venous and arterial flow (41). Qearly, defining the blood compatibility of a material is a conqrromise between a number of these factors. 

FDA testing and previous studies have verified that 150-250 cP is an ideal range for decreased sodium alginate injection resistance in many standard over-the-wire microcatheter systems and increased calcium alginate stability in gel form (Becker et al, 2005 2007). As for newer flow-directed microcatheter systems, an injectable biomaterial requires a lower alginate viscosity range (1-150 cP) to accommodate the microcather s minimal inner diameter. 

Sperling C, Fischer M, Maitz MF, Werner C. Blood coagulation on biomaterials requires the combination of distinct activation processes. Biomaterials 2009 30(27) 4447-56. 

To be compostable the biomaterial requires a controlled microbial environment such as an industrial compost facility before they will degrade. This is because there are requirements of heat, moisture and aeration to activate and sustain the degradation process. To be considered compostable, a material must be able be put into an industrial composting process and breakdown by 90% within six months. Under the European Standard EN 13432 [2] they can be labelled or marked with a compostable symbol. 

To he compostable a biomaterial requires a controlled microbial environment such as an industrial compost facility before they will degrade. 

The third topic in polyphosphazene biomaterials that will be described in this article concerns surface implications. One of the major problems in the utilization of polyphosphazenes in solid state is their exploitation in the construction of implantable devices, for which good physical properties, minimum biological response, and good resistance to fungal or bacterial colonization may be required. 

Decolorization of azo dyes by WRF technology improvements will require integration of all major areas of industrial biotechnology novel enzymes and microorganisms, functional genomics, protein engineering, biomaterial development, bioprocess design and applications. 

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