engleski

Effect of silver nanoparticles on the precipitation of calcium phosphates

Considering the increasing number of post- operative infections caused by antibiotic- resistant bacteria, research of therapeutic alternatives attracts special attention. The development of bioactive antimicrobial coatings for orthopaedic implants is of particular interest, as they can act locally and could reduce the use of oral antibiotics. In this sense, composite coatings based on calcium phosphates (CaPs) and metal or metal oxide nanomaterials have great potential, since CaPs occur naturally in the human body and inorganic nanoparticles do not in principle promote bacterial resistance [1]. Among different nanomaterials, silver nanoparticles (AgNPs) have shown optimal antimicrobial properties and cytocompatibility. In addition, their incorporation into various composite coatings within the organic or inorganic matrix was found to be beneficial, particularly with respect to their potential for controlled release system formulation in situ [2]. This study aimed to develop a green synthesis route for the preparation of novel CaP composites with AgNPs based on the precipitation of CaPs in the presence of AgNPs with different capping agents at different concentrations. For this purpose, two types of AgNPs were synthesised: one stabilised with polyvinylpyrrolidone (PVPAgNP) and the other stabilised with sodium bis(2-ethylhexyl) sulfosuccinate (AOTAgNP) [3]. The progress of precipitation was followed by monitoring the pH changes in the precipitation systems over time. The precipitates obtained after one hour of reaction time were filtered and characterised by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results showed that calcium-deficient hydroxyapatite (CaDHA) was formed both in the absence and presence of AgNPs. SEM micrographs revealed a significant difference in the morphology of the precipitates formed in the different systems, indicating the important influence of the stabilising agent, i.e., the surface composition of the NPs. The results of this study indicate that the formation of CaP composites with metallic nanoparticles should be studied in depth as various parameters can differently affect the process and ultimately the properties of the formed materials. The elucidation of this process is of great importance for the development of improved orthopaedic implants.

calcium phosphates ; silver nanoparticles

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