Patterned surfaces for in vitro hydroxyapatite growth

During the past several decades, hydroxyapatite (HA) has been used in many medical, orthopaedic, and dental applications. In this study, patterning by sequential implantation of Ca and P ion through a mask was used for selective surface modification of three classes of materials (stainless steel, silicon and silica glass). Some of the patterned samples were immersed and simply soaked in a solution resembling human blood plasma (simulated body fluid, SBF). Another solution-based approach, laser-liquid-solid interaction (LLSI), was also employed. The method included a deposition system and a process which allowed simultaneous interaction between a scanning laser beam and the SBF, and also irradiation of the patterned substrates during the laser-liquid interaction, thereby stimulating HA nucleation. The study showed that immediately after the end of the LLSI process in SBF, NaCl dendrite formations and CaP particles were observed, and could be considered as nuclei formed due to the applied LLSI, which further facilitated the growth of the layer.