Micro-Raman spectroscopy study of bio-ceramic surface composition changes
For the last decades, research on bone substitutes processing was often focused on the development of new ceramic shaping methods able to mimic the complex structure of natural bone. Indeed, the human bone is constituted by two kinds of interconnected porous architecture: the cortical bone, called compact bone, with a global porosity of about 65 %, pore sizes between 190 and 230 µm and compressive strength between 80 to 200 MPa and the trabecular bone, called spongious bone, with a higher global porosity (80 %) and larger pore sizes between 500 to 600 µm which gives lower compressive strength of a few tenth MPa. The role of porosity is to permit the cell colonization and vascularization.
Three processes to produce porous ceramic parts were developed by LMCPA-UVHC (the French laboratory) applied to beta-tricalcium phosphate scaffolds: (1) the ceramic slurry impregnation of PMMA bead skeleton which allows the development of isotropic spherical porous structure with 250 to 600 µm pore diameter size, (2) a casting method based on ceramic slurry ice-templating which produces tubular interconnected pores with ellipsoidal shape and smaller diameters (100 to 300 µm), (3) 3D-printing of photosensitive resin loaded by ceramic powder by microstereolithography. These two last techniques lead to columnar porous structure development: the freeze-dried porous material is characterized by elongated and ellipsoidal section pores with sizes of a few tens of microns, so that the pores produced by 3D printing material has continuous channels of square cross-section and of larger size. The tubular porosity structure obtained by these methods presents better compressive strength than the isotropic structure and could favour the cell colonisation inside the implant. This last point has to be confirmed.
The aim of the project is to study surface composition changes of macro-porous beta-tricalcium phosphate scaffolds for bone implants induced during immersion in cells media. The purpose is to understand the influence of shape and the size of pores in ceramics on response of MG63 osteoblasts cells on bio-ceramics, as well as influence cells and/or cell solution on phase transition of ceramic materials, beta-tricalcium phosphates (β-TCP).