Biostable and bioresorbable polymeric composites modified by bioactive ceramics
Patrycja Rosół*, Jan Chłopek*, Carsten Schweder** *Akademia Górniczo-Hutnicza, Wydział Inżynierii Materiałowej i Ceramiki, Katedra Biomateriałów, al. Mickiewicza 30/A3, 30-059 Kraków **University of Applied Sciences Münster, Faculty of Chemical
Quarterly No. 4, 2005 pages 25-30
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abstract Polymer matrix composites are widely applied in medicine. Implants made of these materials have mechanical properties similar to natural tissues, show good biological compatibility, and also can be formed into various shapes. Seen the fact that such composite implants are subject to both biological environments and increased stresses within the real body, extended loads may seriously deteriorate their mechanical properties. In addition, it is the nature of these matrix polymers that their strength decreases with time. Investigations presented in this study show the influence of conditions of simulating human body on the mechanical properties of biostable (polysulfone - PSU) and bioresorbable (poly(lactide-ko-glicolide) - PGLA) polymers and its composites reinforced with hydroxyapatite (HA). The biological properties of polymers and polymer composites was examined in the SBF during 30 days. The pH of solutions and the mass measurements were performed on a weekly basis (Figs 2 and 3). After the 30 days the microstructure was examined using scanning electron microscope (SEM) Jeol JSM-5400 (Figs 5 and 6). The implants’ durability examination was performed by comparison of the results of creep tests in in vitro environments. The so called creep curves were obtained as the result of loading samples with various mechanical stresses (Fig. 4). Their analyses allowed to predict the behaviour of the examined composites under the conditions close to natural (i.e. extended action of mechanical stresses aided by aggressive environment of body fluids). The introduction of HA to polymer matrix decreased mechanical properties but significantly enhanced bioactivity. Since PGLA is a biosorbable material, and it is difficult to predict its long term behaviour on the basis of short-term tests, the long-term creep tests seem to be necessary. Key words: polymer composites, hydroxyapatite, implants, creep