Simple synthetic route for Hydroxyapatite nanoparticles production by ultra-short laser ablation in water

Hydroxyapatite (HAp - Ca10(PO4)6(OH)2) has attracted wide interest for its similarity to bone mineral, excellent biocompatibility and bioactivity. It has been reported that the use of nanostructured HAp leads to a better and more rapid tissue formation with respect to bulk material [1]. Various approaches have been used for the preparation of HAp nanoparticles and their functionalization, such as solid state reaction, hydrothermal, sol-gel methods, etc. However, these methods have drawbacks, such as long reaction time and the use of chemical additives that can be incorporated in the HAp matrix. On the contrary, Pulsed Laser Ablation in Liquid (PLAL) technique, which has been widely used to produce well dispersed nanoparticles, can overcome these requirements. PLAL presents several advantages with respect to the most used chemical methods, such as the possibility to control the nanoparticles size, shape and crystallinity and the possibility to produce pure colloids free of chemical agents or stabilizers [2]. In this contest, we report the simple synthesis of HAp nanoparticles obtained by ultrashort PLAL of a HAp massive target in water using two femtosecond laser sources (Nd:glass 527nm, 250fs and 10 Hz and Ti:Sa 800nm, 100fs and 1kHz). The fabricated HAp nanoparticles have been characterized in terms of their crystallinity, composition and morphology by transmission electron and scanning electron microscopies, X-ray photoelectron and micro-Raman spectroscopies and X-ray diffraction.