Tuning the surface ordering of different charged surfactants for the controlled fabrication of monetite calcium phosphate via microwave synthesis process

Abstract

Morphological aspects of the material exhibits a crucial role in the physiochemical and surface properties of calcium phosphate-based nanostructures. Monetite (CaHPO4), a type of calcium phosphate is one of such material having considerable challenges associated in fabricating defined size and shape. In this study, the search for innovative and economic protocols to fabricate monetite calcium phosphate with differently charged surfactants were employed to investigate the mechanism of morphological variation through microwave assisted technique. It is found that there is significant differences in terms of morphology, size and surface charge of surfactant added monetite. The surfactant-assisted nanostructures were characterised using the X-ray diffraction technique, confirming the formation of calcium phosphate's monetite phase (CaHPO4) with a triclinic crystal system. The crystallite size was found to be 31 nm for pristine and less than 25 nm for surfactant-assisted monetite. Field emission scanning electron microscope analysis reveals the pristine has agglomerated layered formation of monetite, whereas EM (EDTA-Monetite), CM (CTAB-Monetite), and PM (Pluronic F-127-Monetite) portray flower-like petals, hexadentate bricks and bow-knot shape respectively. Furthermore, the biocompatibility of surfactant-assisted monetite particles was assessed with in-vitro protein adsorption studies, which elucidate EM and PM has greater than 600 µg of BSA adsorption rates. But in the case of lysozyme adsorption studies pristine, CM and PM shows more than 800 µg of adsorption owing to the difference in affinity of surface charges in surfactant assisted monetite. The confocal images confirm the presence of dominant live cells in surfactant-assisted monetite.