Tissue biocompatibility

A number of polymer systems were tested for tissue biocompatibility and release kinetics. The best long-term release results were obtained with hydrophobic polymers. Examples included non-degradable ethylene-vinyl acetate or biodegradable polylactic acid. Certain hydrogels such as polyhy-droxyethylmethacrylate or polyvinylalcohol also worked effectively, but released proteins for shorter time periods. With the hydrophobic polymers, biologically active protein was released for more than 100 days (2). In other tests, larger molecules (2 million MW), such as polysaccharides and polynucleotides, were also successfully released for long time periods (2). 

Tetik, R. D., Galante, J. O., and Rostoker, W. (1974), A wear-resistant material for total joint replacement Tissue biocompatibility of an ultra-high-molecular-weight (UHMW) polyethylene-graphite composite, J. Biomed. Mater. Res. 8(5) 231-250. 

Multifilament sutures are more commonly coated than monofilament sutures. For example, multifilament Vicryl and Dexon Plus or Dexon II have coating materials applied, while monofilament PDS and Maxon sutures have no coatings. Traditional coating materials are nonabsorbable bee wax, paraffin wax, silicone and polytetrafluoroethylene (Teflon). New coating materials have been developed, particularly those that are absorbable. This is because the coating materials used for absorbable sutures must also be absorbable (Conn and Beal, 1980 Mattei, 1980 Casey and Lewis, 1986). Absorbable coating materials should also have adequate tissue biocompatibility. 

The first type of poly[(organo)phosphazenes] that can be considered are those with fluoroalkoxy side groups. Subcutaneous in vivo testing of these polymers have shown minimal tissue response (Wade et al., 1978). Poly[(aryloxy)phosphazene]-derivatives also show great promise as inert biomaterials on the basis of preliminary in vivo tissue biocompatibility tests (Wade et al., 1978). 

Miyamoto T, Teikeihashi S, Ito H, Inagaki H, Noishiki Y. Tissue biocompatibility of cellulose and its derivatives. J Biomed Mater Res. 1989 23 125-33. 

Wang X, Gu X, Yuan C et al (2004) Evaluation of PPy with biological tissues biocompatibility of poly pyrrole in vitro and in vivo. J Biomed Mater Res 68A 411-422... 

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