Green synthesis of calcium hydroxide nanoparticles using carob fruit extract and evaluation of their cytotoxic activity

Green synthesis of nanoparticles from plant extracts offers many advantages, such as simplicity, stability, and eco-friendliness. carob fruits (Ceratonia siliqua) are known for their countless health benefits due to their rich antioxidant, mineral, and nutrient contents, and have been used in various biomedical applications. This study aims to green synthesize and characterize carob (C)-mediated calcium hydroxide (CaOH2) nanoparticles (C-CaOH2 NPs), and investigate their cytotoxic activity on hTERT-20 and MG-63 cell lines. C-CaOH2 NPs were synthesized using a combination of carob extract and CaOH2 powder. Characterization was performed using X-ray diffraction (XRD), attenuated total reflection (ATR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Cytotoxic activity was studied using an Alamar Blue assay (AB) at different C-CaOH2 NPs' concentrations (5, 25, 50, 75, and 100 mu g/mL) after 24 and 48 h of exposure, and morphological changes were observed. The SEM results of C-CaOH2 NPs showed a hexagonal shape and TEM result particle distribution size of 31.56-81.22 nm and average of 56.42 nm. The cell viability assay on hTERT-20 and MG-63 showed a dose-dependent effect with biocompatibility at a concentration of 100 mu g/mL or less in both time intervals. The morphological changes observed were consistent with the cell viability results at each concentration, confirming the dose-dependent cytotoxicity. Therefore, this study presents a successful method to synthesize biocompatible C-CaOH2 NPs. They could serve numerous biomedical applications, such as scaffolds for tissue engineering, endodontic medicaments, and dental implant coatings in dentistry. Moreover, this is the first report of carob extract-mediated CaOH2 NPs according to the literature database.