Poly(lactic acid) is nowadays among the most used bioabsorbable materials for medical devices. To promote bone growth on the material surface and increase the degradation rate of the polymer, research is currently focused on organic-inorganic composites by adding a bioactive mineral to the polymer matrix. The purpose of this study was to investigate the ability of a poly(L,DL-lactide)-Bioglass® (P(L,DL)LA-Bioglass(®) 45S5) composite to be used as a bone fixation device. In vitro cell viability testing of P(l,dl)LA based composites containing different amounts of Bioglass(®) 45S5 particles was investigated. According to the degradation rate of the P(L,DL)LA matrix and the cytocompatibility experiments, the composite with 30 wt % of Bioglass® particles seemed to be the best candidate for further investigation. To study its behavior after immersion in simulated physiological conditions, the degradation of the composite was analyzed by measuring its weight loss and mechanical properties and by proceeding with X-ray tomography. We demonstrated that the presence of the bioactive glass significantly accelerated the in vitro degradation of the polymer. A preliminary in vivo investigation on rabbits shows that the addition of 30 wt % of Bioglass(®) in the P(L,DL)LA matrix seems to trigger bone osseointegration especially during the first month of implantation. This composite has thus strong potential interest for health applications.

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The poly(3-hydroxyoctanoate) (PHO) is a biodegradable polyester containing hydrophobic side chains. One way to obtain more hydrophilic polyester consisted in the introduction of polar groups in the side chains. Carboxyl groups (PHO 75 COOH 25 ) were introduced by chemical modifications. The role of carboxyl groups was investigated in the first part as potential support for cell seeding by studying the cell adhesion and proliferation, and in the second part as potential drug carrier by comparing the abilities of PHO and PHO 75 COOH 25 to form degradable particles. Measurements of human bladder RT112 cells adhesion were done with or without collagen IV. Adhesive RT112 cells were counted by a colorimetric MTT test. The results showed that the COOH pendant groups of PHO 75 COOH 25 films promoted cell adhesion after 4 h of incubation. The proliferation of cells is not improved after 4 days of incubation because of a reorganization of macromolecular chains and reorientation of COOH groups. This surface restructuration when the film was in contact with water was showed by contact angle measurements. We showed that the presence of COOH groups modified the hydrophobic/hydrophilic balance and enhanced the formation of particles. Stable lyophilisable particles were then obtained with diblock copolymer P(HO 75 COOH 25 -b-CL); the caprolactone block (CL) was necessary to improve particles stability. The results showed that the release of doxorubicin from the particles is enhanced in presence of hydrophilic and degradable block (PHO 75 COOH 25 ). It was possible to obtain a degradable functional polyester based on PHO with carboxyl pendant groups to improve degradation rate by simple hydrolysis required for drug delivery systems.