Synthesis and characterisation of nanocrystalline Ca–Al layered double hydroxide {[Ca 2 Al(OH) 6 ]NO 3 .nH 2 O}: in vitro study

In this study, Ca–Al–NO3 layered double hydroxide (LDH) nanoparticles of varying sizes were synthesised by a process involving co-precipitation under hydrothermal condition. This method produces stable homogeneous LDH suspensions under variable hydrothermal treatment conditions with particle size in the range of 7·5–2·5 μm. Layered double hydroxides were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, thermal gravimetric/differential thermal analysis, scanning electron microscopy and transmission electron microscopy (TEM) and nanosizer analyses. By increasing the hydrothermal treatment time, the crystallinity and the particle size of obtained LDH increased. Scanning electron microscopy and TEM observations showed uniform hexagonal flake-like particles with high aspect ratio. Finally, Ca–Al–NO3 LDH did not show any acute cytotoxic effect up to 100 μg mL−1 as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.