Polymer-ceramic nanocomposites for biomedical applications
Patrycja Rosół, Jan Chłopek Akademia Górniczo-Hutnicza, Wydział Inżynierii Materiałowej i Ceramiki, al. Mickiewicza 30, 30-059 Kraków
Quarterly No. 1, 2006 pages 39-44
DOI:
keywords: polymer composites, hydroxyapatite, implants, mechanical properties
abstract From the point of view of implant’s application in bone-surgery, the most important properties of the material to be considered are: the ability of regeneration of surrounding tissues and the enhanced durability in biological environment. The regeneration function may be assured by the application of bioactive ceramic materials, including primarily the calcium phosphates, bio-glasses as well as glass-ceramics. The realization of biomechanical function requires on one hand the adjustment of Young’s moduli of the implant and the surrounding tissue, and on the other, carrying the largest portion of stresses by the implant, according to the type of joint applied. In this work the effects of modifying phases on mechanical and biological properties of polysulfone (PSU) have been examined under in vitro conditions. Hydroxyapatite of nanoparticles both, natural origin (animal bones, Fig. 1) and synthetic have been used as modifying phases. Durability of testing materials was defined basing on creep tests in in vitro conditions (Fig. 5) and bioactivity was based on SEM observations of samples surface incubated in artificial biological environment (Fig. 6). Analysis of durability obtained from creep tests investigations indicated that polysulfone can be safetly worked on level 27% of initial strenght for specific healing times (6 weeks). Similarly, of composite modified by natural hydoxyapatite (PSU/HAn) value of permissible stress is about 28% his initial strenght, whereas for composite modified by synthetic hydroxyapatie (PSU/HAs) is only 13%. Lesser durability PSU/HAs in vitro conditions is possibly connected with change of state composite interfaces: ceramic-polymer particles in effect penetration of physiological liquid into samples. Moreover, in case of this composite, was observed non-uniform distribution of synthetic hydroxyapatite in polysulfone matrix and creating of agglomerate by his particles (Fig. 3), which exert a disadvantageous influence on exploitation properties of material. Biological investigations indicated that modification of polysulfone by introducing hydroxyapatie nanoparticles gives bioactive feature and also type of hydroxyapatite has a meaningful influence on process of growing hydroxyapatite in simulated body fluid.