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The micro-arc oxidation (MAO) coatings were fabricated on the surface of the microwave sintered Ti-15Mg metal-metal composite (MMC). The surface morphologies, phase composition, degradation properties and cytocompatibility of the MAO treated Ti-15Mg MMC were investigated. The XRD and XPS results show that the MAO coatings are mainly composed of anatase and rutile TiO2 crystal phases and amorphous MgO and SiO2 with some –OH groups. There are some differences between MAO pore structure in Ti region and Mg region, but both of the pore sizes increase and the number of pores decreases with increasing the applied voltages. The degradation rate of Ti-15Mg MMC is reduced by the MAO coatings, and with increasing the applied voltages, the degradation rates of the MAO treated samples decrease first, reaching the minimum value at 300 V, and then increase. After immersed in SBF solution for 250 h, the calcium-deficient apatite containing CO32− is detected on the surface of the MAO treated and untreated Ti-15Mg MMC. The results of cell viability and alkaline phosphatase activity show that the MAO treated Ti-15Mg MMCs are more conducive to the proliferation and differentiation of MG-63 cells.

Polyactive 1000PEOT70PBT30 (a segmented block copolymer of poly(ethylene oxide terephtalate)/poly(butylene terephtalate) with 70/30 PEOT/PBT ratio) was processed into three different types of samples: injection molded to rods, hot-pressed to films and to composite membranes made by hot-pressing a tubular mesh of poly-L,D-lactide 96/4 between two films of Polyactive. The molecular weight of Polyactive was not influenced by processing, but gamma-sterilization seemed to increase the weight average molecular weight (Mw). Mechanical properties of the rods and films decreased rapidly in hydrolytic conditions due to the hydrogel nature of the polymer, swelling and degradation. Mesh reinforcement increased the mechanical properties, but the components separated during soaking. In vitro the molecular weight of the rods and films started to decrease immediately, but the PEOT (or PEO) proportion remained relatively constant for 26 weeks. Macroscopically, all the wet devices remained intact, but fragmented on drying. Microscopically, topographical formations of polymer were found on the surfaces and small sodium-rich spots were precipitated onto and inside the polymer. Thermal measurements showed that polymer consisted of amorphous PEOT segments and both amorphous and crystalline PBT segments.

International audience; The objective of this work was to develop and study newbiodegradable thermoplastics with improvedmechanical properties for potential use as temporary implantable biomaterials. Linear poloxamer and star-shaped poloxamine have been used as macroinitiators for the ring-opening polymerization (ROP) of lactide to yield high molecular weight PLA-based thermoplastic block copolymers. The influence of the nature of the macroinitiator, PLA crystallinity and initial molecular weight on the copolymers properties was investigated by performing a 7-week degradation test in PBS. The evaluation of water uptakes and molecular weights during the degradation pointed out an early hydrolytic degradation of the 100-kg∙mol−1 copolymers compared to the 200-kg∙mol−1 ones (molecular weight decrease of ca. 40% and 20%, respectively). A dramatic loss of tensile mechanical properties was also observed for the 100-kg∙mol−1 copolymers, whereas the 200-kg∙mol−1 copolymers showed stable or even slightly improved properties with Young's moduli around 500 MPa and yield strains around 3% to 4%. Finally, the cytocompatibility of the more stable 200 kg∙mol−1 copolymers was confirmed by murine mesenchymal stem cells (MSCs) culture.