PIM-structured multi-element doped calcium phosphates implants for large bone defects regeneration – PIMyBone

With population ageing worldwide, there is a constant increase in need for bone filling material in order to treat critical bone defect. Actually long bone defects are particularly challenging for regenerative medicine. To date, no adequate scaffold able to promote tissue ingrowth within such a context is available. The current synthetic bone substitutes have a weak capacity to stimulate the neo-tissue formation, to limit the risk of infection and can induce an inflammation deleterious for the durability of the implant. Moreover, ceramic substitutes are naturally brittle with limited ergonomics, which make them difficult to use in certain conditions (anatomical sites present variable access, geometry and mechanical stress). The ionic doping of porous bioceramics based on calcium phosphates (CaP) could be used to overcome the first difficulties mentioned, using strontium (Sr2+), copper (Cu2+) and zinc (Zn2+) respectively, while the use of an interlocking or breakable ceramic scaffold, as well as biobased shape memory composite could make it possible to overcome the second limitation. Thus, our PIMyBone program aims to develop, to characterize (physically, chemically and mechanically), and to evaluate biologically (in vitro and in vivo) two therapeutic solutions via macroporous scaffolds either ceramics or hybrid ceramics/shape memory composite. These three-dimensional structures will be shaped by the same optimized PIM (Powder Injection Moulding) process using additive manufacturing tools, in order to obtain complex custom geometries with multiple porosity levels, to allow use in any indication and regardless of the geometry of the bone defect.