Application of sonochemistry for formation of nanosized silver and silver/hydroxyapatite composite particles

Abstract

Development of nanotechnology during last few decades gave significant contribution to different areas of research especially in biomedical sciences and improved characteristics of many biomaterials allowing their commercial application [1,2]. One of the representative examples is the development of nanomedicine, a new field of medical research which opened the possibility for interactions between nanomaterials and pathogens at the same scale of size [3]. This approach allowed development of nano-therapeutics, biosensors and point-of-care molecular diagnostic devices resulting in target, localized and more efficient medication [4]. So far, different techniques are applied for formation of these materials. Among them, sonochemical synthesis can be separated as a method based on the high temperature and pressure combined with intensive mixing induced by acoustic cavitation and micro jets. This method enables control over size, morphology and nano-/micro-structure of materials that are often unavailable by conventional methods [5]. The main goal of our work is application of the sonochemical synthesis method for preparation of nanosized particles of silver and silver composite with hydroxyapatite, as well-known bioactive and osteoconductive bioceramics for potential application in biomedicine as bone-defects filler with preventive antiinflammatory properties. Urea, known as a homogeneous precipitation agent, was applied as capping agent of silver which allowed formation of silver complex able to be decomposed at 300De and to form nanosized silver particles up to 20 nm in size. In the case of co-precipitation of silver with hydroxyapatite particles, after thermal decomposition of silver complex, hydroxyapatite/silver composite was obtained. At such conditions, uniform distribution of nanosized silver particles, with the size up to 10 nm, located onto the surface of hydroxyapatite submicrometre-sized rod-like particles, was obtained. These changes of the morphological properties of nano-silver, and its distribution, suggested a possible influence of hydroxyapatite surface on the mechanism of silver particles' growth. From the side of applicability, importance of obtained HAp/Ag composite morphology can be addressed to the well-known size-related dependence of antibacterial activity of metallic silver particles which showed significant improvement of this property of silver particle with the size in the range between I and 10 nm. This can be correlated to its possible application in orthopedics and dentistry.