Sustainable calcium oxide nanoparticles based on agroindustry waste for potential endodontics applications

Abstract

Development of sustainable proposals in various areas has been crucial nowadays. Thus, this research evaluated a sustainable synthesis of calcium oxide nanoparticles (CaO NPs), using an agroindustry waste from eggshells to promote dentistry tissue regeneration with antimicrobial activity. Then, eggshells were loaded to heat treatment with two different temperatures (700 °C and 900 °C) for three times (7, 15 and 24 h). These CaO NPs were characterized using spectroscopies (UV Vis, FTIR, XRD) and morphological (ZP, SEM, TEM). Additionally, antimicrobial activity against Escherichia coli and Candida albicans, cell viability, protein adsorption and alkaline phosphatase activity were evaluated. The results showed that CaO NPs were produced in both temperatures, but in the slow heating (at 700 °C), Ca(OH)2 was still presented. Moreover, morphological analysis showed charges close to zero, indicating high agglomeration of nanoparticles proved by SEM images. The CaO NPs’ size were in the range of 10 and 25 nm at 900 °C and showing high clustering and porosity at 700 °C by TEM analysis, and the band gap, 2.82–5.77 eV. Additionally, XRD showed nanoparticles of CaO and Ca(OH)2 in both temperatures, although in the case of high heating, the presence of more CaO was perceived. The cell viability was great for biological proposals, mainly in the sample performed at high temperature (over 90 %). Furthermore, the antimicrobial activity showed incredible results against both microbials with low calcium nanoparticles tested (40 μg). Thus, this research demonstrated a sustainable way to reusability agroindustry waste for dentistry applications.