Improved suspension stability of calcium carbonate nanoparticles by surface modification with oleic acid and phospholipid

We prepared and characterized calcium carbonate nanoparticles (CC NPs) that were surface-modified with oleic acid (OA) and phosphatidylcholine (PC) in order to improve their suspension stability in an aqueous solution. The improvement in the suspension stability of CC NPs in an aqueous solution may be helpful to extend their applicability to a wider range of biological applications. The CC NPs were coated with OA by making use of their electrostatic potential and were then decorated with PC. The CC NPs surface-modified with OA and PC were successfully constructed, and the existence of the decorated OA and PC in the surface of the PC-OA-CC NPs was observed via transmission electron microscopy (TEM) and was confirmed by thermo gravimetric analysis (TGA), Xray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) analyses. The PC-OA-CC NPs floating in an aqueous solution exhibited better stability when compared to non-surface-modified CC NPs. The DLS and TEM results revealed that the degree of size agglomeration for the CC NPs was significantly reduced by the surface modification with OA and PC. The PC-OA-CC NPs showed a very low cytotoxicity at a high concentration in terms of the cell viability of the RAW264.7 cells. Consequentially, the stability in suspension of the CC NPs in an aqueous solution could be effectively improved through surface-modification with OA and PC. PC-OACC NPs could be useful in increasing the range biological applications for CC NPs.