Use of ultrasound in the synthesis of apatite

The ultrasonic assisted synthesis of apatite is an ideal technique to be used in the production of nanostructured compounds. In medicine, porous apatite nanostructures have become a widely used material in bone regeneration processes. Sonication is a process where an acoustic field coupled to a liquid medium is used. Ultrasonic waves propagate in the liquid causing a process known as cavitation. This process generates an extreme force that results in collisions between particles causing a decrease in their size. This reduction in size may generally have particles in the order of submicrons and nanos. The objective of the work in this research was to evaluate the influence of ultrasound during the process of synthesis of different apatite phases. Three phases of apatite according to the described methodology in the literature were synthesized. During the synthesis process, ultrasound was used. The material obtained was tray dried at 80°C for 24 hours and characterized by X-ray Powder Diffraction, FTIR spectroscopy and Scanning Electron Microscopy. Particle size by scanning electron microscopy was determined. The results showed that the material obtained presents similar parameters to the material obtained by synthesis without ultrasound, but with a smaller particle size. Key Word: Apatite, Ultrasound, Tray Drying, Biomaterials, Particle size INTRODUCTION In the last decades, biomaterial researches and high investments in the industry have provided the development of a large number of different bone substitutes, which aims to reduce the need for the use of autogenous bone grafts. Ceramics, glass and glass ceramics are part of the biomaterials class used in the repair or replacement of hard connective tissues. The resorbable ceramics, such as calcium phosphates and some bioactive glasses (particulate or porous form) in bone regeneration procedures are used. Currently, synthetic calcium phosphates are the principal compounds studied and used as biomaterials in there placement and regeneration of bone tissue (Guastaldi et al., 2010; Dorozhkin, 2007, 2009, 2010a, 2010b, 2010c; Raynaud et al, 2001). The use of ultrasound or microwave during the synthesis process has been reported (Giardina et al., 2010; Zhang et al., 2007; Gedanken, 2004; Kim et al., 2000; Lopez et al., 1998; Jarcho et al., 1976). The ultrasound technique may be an alternative for the synthesis of calcium phosphates, based on properties involving the ultrasound process. Sound waves are mechanical waves produced by deformations caused by the pressure difference in an elastic or deformable medium. These waves need a medium to propagate causing a phenomenon known as cavitation (Polloni, 2014; Mizukoshi et al., 1999). This process allows the production of small particles in the form of nanoparticles. In the present work, the objective of the research was to evaluate the influence of ultrasound during the process of synthesis of different phases of apatite and using the tray drying method. 14° Congresso da Sociedade Latino Americana de Biomateriais, Orgãos Artificiais e Engenharia de Tecidos SLABO 5a Edição do Workshop de Biomateriais, Engenharia de Tecidos e Orgãos Artificiais OBI 20 a 24 de Agosto de 2017 Maresias SP Brasil