University of Guilan Aquatic Physiology and Biotechnology 2345-3966 12 1 2024 06 19 Evaluating the effectiveness of seaweed, Sargassum ilicifolium, extract and animal extract of brittle star, Ophiocoma scolopendrina, in the amount of ultraviolet ray absorption by cerium oxide nanoparticles Evaluating the effectiveness of seaweed, <i>Sargassum ilicifolium</i>, extract and animal extract of brittle star, <i>Ophiocoma scolopendrina</i>, in the amount of ultraviolet ray absorption by cerium oxide nanoparticles 19 39 7618 10.22124/japb.2024.25709.1516 FA Mahdie Amiri Nezhad Ph.D. Student in Marine Biology, Department of Marine Biology, Faculty of Marine Science and Technology, University of Hormozgan, Bandar Abbas, Iran Narges Amrollahi Biuki Associate Professor in Department of Marine Biology, Faculty of Marine Science and Technology, University of Hormozgan, Bandar Abbas, Iran Morteza Yousefzadi Professor in Department of Biology, Faculty of Sciences, University of Qom, Qom, Iran Arash Ghaderi Associate Professor in Department of Chemistry, Faculty of Sciences, University of Hormozgan, Bandar Abbas, Iran Journal Article 2023 10 03 Today, green synthesis methods of nanoparticles are increasing. This research was aimed at investigating the synthesis of cerium oxide nanoparticles (CeO₂-NPs) using <em>Sargassum ilicifolium</em> and <em>Ophiocoma scolopendrina</em> extracts and confirming the protective effect as well as the stability of the cream formulation with cerium oxide nanoparticles against UVR. The obtained products were identified using XRD, TEM, SEM and UV-Vis. Then cream samples were prepared with concentrations of 0, 0.5, 2, 4 and 8% CeO₂-NPs. Based on the results, the nanoparticles were spherical in shape and had a cubic crystal structure with a size of about 10-12 nm. The peak between 290-320nm corresponded to UVB and the absorption spectrum of the synthesized CeO₂-NPs showed absorption peaks at 317 and 315nm wavelengths. Formulation F5 of sunscreen containing nanoparticle synthesized from <em>S. ilicifolium</em> with SPF 25 and critical wavelength (λ_C) 380.4nm showed the highest protection factor. According to the star rating, it had four stars. The cream formulation was completely homogeneous and stable in the cooling-heating cycle. Also, the pH was close to the pH of human skin. The results of MTT test to investigate the toxicity of CeO₂-NPs on HFF cell line, indicated that the treated cells did not show significant toxicity compared to the control. According to the results of this study, CeO₂ nanoparticles have the necessary conditions for progress in solar protection technology. Today, green synthesis methods of nanoparticles are increasing. This research was aimed at investigating the synthesis of cerium oxide nanoparticles (CeO₂-NPs) using <em>Sargassum ilicifolium</em> and <em>Ophiocoma scolopendrina</em> extracts and confirming the protective effect as well as the stability of the cream formulation with cerium oxide nanoparticles against UVR. The obtained products were identified using XRD, TEM, SEM and UV-Vis. Then cream samples were prepared with concentrations of 0, 0.5, 2, 4 and 8% CeO₂-NPs. Based on the results, the nanoparticles were spherical in shape and had a cubic crystal structure with a size of about 10-12 nm. The peak between 290-320nm corresponded to UVB and the absorption spectrum of the synthesized CeO₂-NPs showed absorption peaks at 317 and 315nm wavelengths. Formulation F5 of sunscreen containing nanoparticle synthesized from <em>S. ilicifolium</em> with SPF 25 and critical wavelength (λ_C) 380.4nm showed the highest protection factor. According to the star rating, it had four stars. The cream formulation was completely homogeneous and stable in the cooling-heating cycle. Also, the pH was close to the pH of human skin. The results of MTT test to investigate the toxicity of CeO₂-NPs on HFF cell line, indicated that the treated cells did not show significant toxicity compared to the control. According to the results of this study, CeO₂ nanoparticles have the necessary conditions for progress in solar protection technology. https://japb.guilan.ac.ir/article_7618_8791621c3460ce1693fbc6daea821a25.pdf