Photoprotective activity of zirconia nanoparticles

• Published in: Colloids and surfaces, B, Biointerfaces B, Biointerfaces, 2021-06, Vol.202, p.111636-111636, Article 111636
• Main Authors: de Sá, Renata Guimarães, Arantes, Tatiane Moraes, de Macedo, Erenilda Ferreira, Dona', Luísa Molina, Pereira, Jeniffer C.F., Hurtado, Carolina Ramos, Varghese, R. Jose, Oluwafemi, Oluwatobi Samuel, Tada, Dayane Batista
• Format: Article
• Language: English
• Subjects: Photoprotection; UV irradiation; Zirconia nanoparticles
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/j.colsurfb.2021.111636

[Display omitted] •Synthesis of ZrO2 NPs by hydrothermal method with monoclinic crystalline structure and average diameter of (50 ± 12 nm).•High stability in suspension: high Zeta potential (+ 48 mV) and low polydispersity index (0.09).•Low cytotoxicity against keratinocytes cells (HaCaT).•Photoprotective effect in HaCaT cells under UV irradiation. The increasing incidence of diseases caused by the harmful effects of UV radiation in skin, predominantly skin cancer, induce the search for more efficient photoprotector agents. Nowadays, titanium dioxide (TiO2) and zinc oxide (ZnO) are the most widely used photoprotectors and therefore form the main components of commercially available sunscreens. Although the outstanding efficiency in absorbing and scattering UV radiation, mainly as nanoparticles, recent studies have raised concerns regarding the safe use of these nanoparticles, especially due to their high generation of reactive oxygen species (ROS). Thereby, this work focus on the evaluation of the photoprotective activity of zirconia nanoparticles (ZrO2 NPs) and their cytotoxicity study in the presence and absence of UV irradiation. The ZrO2 NPs were synthesized by hydrothermal method and their hydrodynamic diameter, Zeta potential and colloidal stability were characterized by dynamic light scattering. The morphology and size were observed by transmission electron microscopy. The synthesis resulted in ZrO2 NPs with 50 nm of diameter and 56 nm of hydrodynamic diameter. The high colloidal stability was evidenced by the high value of Zeta potential (+48 mV) and low polydispersity index (0.09). The UV–vis spectrum of the ZrO2 NPs in aqueous suspension showed an intense light scattering below 250 and a wide absorption band at 285 nm. The poor generation of ROS by ZrO2 NPs was confirmed by the absence of photodegradation of methylene blue after long periods of irradiation. The in vitro assays performed with HaCaT cell line showed that the cell viability did not decrease in the absence of irradiation. However, after 24 h of incubation, the cell viability decreased under UV-irradiation in comparison with irradiated cells that were not incubated with ZrO2 NPs. Notably, in these assays, the cells were incubated with the ZrO2 NPs and after 24 h, they were replaced by fresh culture medium before the cell viability assay. Nevertheless, another in vitro assay was performed in order to evaluate the photoprotective activity of ZrO2 NPs. The cells were irradiated in the pr