Influence de la géométrie des pores sur la vascularisation d’implants en hydroxyapatite silicatée fabriqués par microstéréolithographie

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Influence of pore geometry on vascular colonization of porous silicon-substituted hydroxyapatite ceramics shaped by microstereolithography

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Quantitative analysis of vascular colonization and angio-conduction in porous microstereolithographied silicon-substituted hydroxyapatite with various pore shapes in a chick chorioallantoic membrane (CAM) model

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Additive Manufacturing to Produce Complex 3D Ceramic Parts

International audienceAttempts to improve the performance of ceramic parts have recently led to advances in their design and in the processes used to tailor these parts. Thus, Additive Manufacturing (AM) technologies, initially developed in the polymers and metals industries, have become of increasing interest for shaping ceramic parts. Among AM techniques, photopolymerization (referred to as stereolithography (SLA) and micro-stereolithography) makes it possible to reach high accuracy that matches the design requirements for new applications of ceramics in a wide range of fields. The development by means of (micro)-stereolithography of complex 3D ceramic parts with improved performance requires the mastering of various parameters linked to the inorganic-organic system involved in this processing route. This paper reports on some recent achievements in the production of ceramics using photopolymerization. Some examples of the work performed at the SPCTS laboratory to produce complex 3D ceramic parts for applications in the fields of information and communication technologies, healthcare and jewellery are presented

Microporous Hydroxyapatite-Based Ceramics Alter the Physiology of Endothelial Cells through Physical and Chemical Cues

Incorporation of silicate ions in calcium phosphate ceramics (CPC) and modification of their multiscale architecture are two strategies for improving the vascularization of scaffolds for bone regenerative medicine. The response of endothelial cells, actors for vascularization, to the chemical and physical cues of biomaterial surfaces is little documented, although essential. We aimed to characterize in vitro the response of an endothelial cell line, C166, cultivated on the surface CPCs varying either in terms of their chemistry (pure versus silicon-doped HA) or their microstructure (dense versus microporous). Adhesion, metabolic activity, and proliferation were significantly altered on microporous ceramics, but the secretion of the pro-angiogenic VEGF-A increased from 262 to 386 pg/mL on porous compared to dense silicon-doped HA ceramics after 168 h. A tubulogenesis assay was set up directly on the ceramics. Two configurations were designed for discriminating the influence of the chemistry from that of the surface physical properties. The formation of tubule-like structures was qualitatively more frequent on dense ceramics. Microporous ceramics induced calcium depletion in the culture medium (from 2 down to 0.5 mmol/L), which is deleterious for C166. Importantly, this effect might be associated with the in vitro static cell culture. No influence of silicon doping of HA on C166 behavior was detected

Quantitative analysis of vascular colonisation and angio-conduction in porous silicon-substituted hydroxyapatite with various pore shapes in a chick chorioallantoic membrane (CAM) model

International audienceThe development of scaffolds for bone filling of large defects requires an understanding of angiogenesis and vascular guidance, which are crucial processes for bone formation and healing. There are few investigations on the ability of a scaffold to support blood vessel guidance and it this is of great importance because it relates to the quality and dispersion of the blood vessel network. This work reports an analysis of vascularisation of porous silicon-substituted hydroxyapatite (SiHA) bioceramics and the effects of pore shape on vascular guidance using an expedient ex ovo model, the chick embryo chorioallantoic membrane (CAM) assay. Image analysis of vascularised implants assessed the vascular density, fractal dimension and diameter of blood vessels at two different scales (the whole ceramic and pores alone) and was performed on model SiHA ceramics harbouring pores of various cross-sectional geometries (circles, square, rhombus, triangles and stars). SiHA is a biocompatible material which allows the conduction of blood vessels on its surface. The presence of pores did not influence angiogenesis related-parameters (arborisation, fractal dimension) but pore geometry affected the blood vessel guidance and angio-conductive potential (diameter and number of the blood vessels converging toward the pores). The measured angles of pore cross-section modulated the number and diameter of blood vessels converging to pores, with triangular pores appearing of particular interest. This result will be used for shaping ceramic scaffolds with specific porous architecture to promote vascular colonisation and osteointegration

Influence of microporosity and macropores design upon cell colonization of calcium phosphate ceramic scaffolds for bone regeneration

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Pre-osteoblast cell colonization of porous silicon substituted hydroxyapatite bioceramics: Influence of microporosity and macropore design

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A new custom made bioceramic implant for the repair of large and complex craniofacial bone defects

International audienceNeurosurgery and Maxillofacial Surgery Departments of Limoges University Hospital Centre have developed a new concept of a custom made ceramic implant in hydroxyapatite (HA) for the reconstruction of large and complex craniofacial bone defects (more than 25 cm2). Materials and methods: The manufacturing process of the implants used a stereolithography technique that produces implants with three-dimensional shapes derived directly from the scan file of the patient's skull without moulding or machining. Eight patients received 8 implants between 2005 and 2008. Results: The surgical procedure is simple and fast. The post-operative follow-up was 12 months. No major complications (infection or fracture of the implant) were observed. The cosmetic result was considered satisfactory by both patients and surgeons. Conclusions: These new implants are well suited for reconstruction of large craniofacial bone defects (greater than 25 cm2) in adults and children over 8 years. 2012 European Association for Cranio-Maxillo-Facial Surgery

Elaboration of osteoinductive phosphocalcic bioceramics for bone tissue engineering

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