Cuttlefish bones are an inexpensive source of calcium carbonate, which are produced in large amounts by the marine food industry, leading to environmental contamination and waste. The nontoxicity, worldwide availability and low production cost of cuttlefish bone products makes them an excellent calcium carbonate precursor for the fabrication of hydroxyapatite. In the present study, a novel oil-bath-mediated precipitation method was introduced for the synthesis of hydroxyapatite (Hap) nanorods using cuttlefish bone powder as a precursor (CB-Hap NRs). The obtained CB-Hap NRs were investigated using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) techniques to evaluate their physicochemical properties. The crystallite size (20.86 nm) obtained from XRD data and the elemental analysis (Ca/P molar ratio was estimated to be 1.6) showed that the Hap NRs are similar to that of natural human bone (≈1.67). Moreover, the FTIR data confirmed the presence of phosphate as a functional group and the TGA data revealed the thermal stability of Hap NRs. In addition, the antibacterial study showed a significant inhibitory effect of CB-Hap NRs against S. aureus (zone of inhibition - 14.5 ± 0.5 mm) and E. coli (13 ± 0.5 mm), whereas the blood compatibility test showed that the CB-Hap NRs exhibited a concentration-mediated hemolytic effect. These biogenic CB-Hap NRs with improved physicochemical properties, blood compatibility and antibacterial efficacy could be highly beneficial for orthopedic applications in the future.
Developments in nanotechnology field, specifically, metal oxide nanoparticles have attracted the attention of researchers due to their unique sensing, electronic, drug delivery, catalysis, optoelectronics, cosmetics, and space applications. Physicochemical methods are used to fabricate nanosized metal oxides; however, drawbacks such as high cost and toxic chemical involvement prevail. Recent researches focus on synthesizing metal oxide nanoparticles through green chemistry which helps in avoiding the involvement of toxic chemicals in the synthesis process. Bacteria, fungi, and plants are the biological sources that are utilized for the green nanoparticle synthesis. Due to drawbacks such as tedious maintenance and the time needed for the nanoparticle formation, plant extracts are widely used in nanoparticle production. In addition, plants are available all over the world and phytosynthesized nanoparticles show comparatively less toxicity towards mammalian cells. Secondary metabolites including flavonoids, terpenoids, and saponins are present in plant extracts, and these are highly responsible for nanoparticle formation and reduction of toxicity. Hence, this article gives an overview of recent developments in the phytosynthesis of metal oxide nanoparticles and their toxic analysis in various cells and animal models. Also, their possible mechanism in normal and cancer cells, pharmaceutical applications, and their efficiency in disease treatment are also discussed.