Characterisation of the pulsed-laser induced phase transformation and osteogenic properties of photo-active iron-calcium phosphate biomineral

Personalised medicine and near patient manufacturing are two emerging concepts in tissue engineering. They are based on the design and manufacture of individual bone grafts which are dependent on the needs of individual patients. To date, the most efficient method to achieve this is through selective laser sintering (SLS), which has been one of the most developed and successfully applied techniques [2]. Various forms of calcium phosphates (CaP) have been used so far for scaffold manufacturing through SLS because of their compositional and structural similarity with the mineral within human bone and teeth. The main drawback of bone and tissue-like materials has been the lack of vascularisation which limits blood supply to essential healing areas. Recently there has been an increasing interest in Fe2+\Fe3+ doped calcium phosphates due to the essential function of iron in regulating oxygen through hemoglobin in human body [3]. In addition, it was reported that doping brushite (CaHPO4.2H2O) with Fe2+/Fe3+ ions, improved energy absorption and controlled the volume of energy absorbed region [4]. The Incorporation of Fe within CaP’s lattice resulted in the characteristic thermal phase transformation temperatures to shift to lower values, thereby promoting densification and sintering. The aim of the present work is to identify an optimum doping concentration of sintered β-CPP (Ca2P2O7) doped with Fe ions. The mechanical properties, biological response and the scaffold fabrication potential in relation to laser-matter interaction will be fully investigated. Various concentrations of iron (0 mol%, 5 mol%, 10 mol%, 20 mol% and 30 mol% by substituting ca2+) doped brushite powder were synthesised and sintered at temperature of 1000oC for 5hrs. A femtosecond pulse laser emitting at a wavelength of 800 nm with 1 KHz repetition rate was used to create micro-channels in the surface of the samples to investigate the effect of surface properties in cell behaviour.