Biomaterial biostable

Polyurethanes as Biomaterials. Much of the progress in cardiovascular devices can be attributed to advances in preparing biostable polyurethanes. Biostable polycarbonate-based polyurethane materials such as Corethane (9) and ChronoFlex (10) offer far-reaching capabiUties to cardiovascular products. These and other polyurethane materials offer significant advantages for important long-term products, such as implantable ports, hemodialysis, and peripheral catheters pacemaker interfaces and leads and vascular grafts. 

Successful applications of materials in medicine have been experienced in the area of joint replacements, particularly artificial hips. As a joint replacement, an artificial hip must provide structural support as well as smooth functioning. Furthermore, the biomaterial used for such an orthopedic application must be inert, have long-term mechanical and biostability, exhibit biocompatibility with nearby tissue, and have comparable mechanical strength to the attached bone to minimize stress. Modem artificial hips are complex devices to ensure these features. 

Kim K, Kim C, Byun Y. Biostability and biocompatibility of a surface-grafted phospholipid monolayer on a solid substrate. Biomaterials 2004, 25, 33-41. 

Based on their behavior in living tissue, polymeric biomaterials can be divided into two groups biostable and biodegradable. Biostable polymers are used when permanent aids are needed, e.g., as prostheses [13]. Biostable polymers, typically polyethylene and poly(methyl methacrylate), should be physiologically inert in tissue conditions and maintain their mechanical properties for decades [11]. 

Hergenrother, R.W., H.D. Wabers, and S.L. Cooper, Effect of hard segment chemistry and strain on the stability of polyurethanes in vivo biostability. Biomaterials, 1993, 14, 449 58. 

Wabers, H.D., et al., Biostability and blood-contacting properties of sulfonate grafted polyurethane and Biomer. Journal of Biomaterial Science Polymer Edition, 1992, 4, 107-133. 

Ma L, Gao CY, Mao ZW et al (2003) Collagen/chitosan porous scaffolds with improved biostability for skin tissue engineering. Biomaterials 24 4833-4841... 

D. Martin, L. Warren, P. Gunatillake, S. McCarthy, G. Meijs, K, Schindhelm, Polydimethylsiloxane/polyether-mixed macrodiol-based polyurethane elastomers biostability. Biomaterials 21 (10) (2000) 1021-1029. 

A. Simmons, J. Hyvarinen, R. Odell, D. Martin, P. Gunatillake, K. Noble, L. Poole-Warren, Long-term in vivo biostability of poly(dimethylsiloxane)/poly(hexamethylene oxide) mixed macrodiol-based polyurethane elastomers. Biomaterials 25 (20) (2004) 4887-4900. 

A. Simmons, A. Padsalgikar, L. Eerris, L. Poole-Warren, Biostability and biological performance of a PDMS-based polyurethane for controlled drug release. Biomaterials 29 (20) (2008) 2987—2995. 

A.J. Coury, Chemical and biochemical degradation of polymers intended to be biostable, in B.D. Ratner, A.S. Hoffman, F.J. Schoen, J.E. Lemons (Eds.), Biomaterials Science An Introduction to Materials in Medicine, third ed.. Academic Press, Elsevier, Waltham, MA, USA, 2013. 

G. Hamilton, In vivo biostability of a poly(carbonate-urea)urethane graft. Biomaterials 24 (2003) 2549-2557. 

Presently enzymes can hardly be used to degrade artificial synthetic polymers unless it is under special conditions. It is worth noting that compounds like poly(vinyl alcohol), PVA, bacterial polymers and poly(e-caprolatone), PCL, that are biodegradable under outdoor conditions are degraded abiotically and thus very slowly in an animal body where they are not biodegradable. Despite this difficulty the number of artificial polymers proposed as biodegradable biomaterial candidates to replace biopolymers or biostable polymers is increasing. 

Stokes, K., Mcvenes, R. Anderson, J. M. (1995) Polyurethane elastomer biostability. Journal of Biomaterials Applications, 9, 321-354. 

---