“…Numerous studies exposed ex vivo sheep, goat, or porcine nasal mucosa or toad palate to nanoparticles for 0.5–24 h and used light microscopy to assess H&E stained tissue morphology. Most studies showed no gross morphological or histological changes (Abdelbary & Tadros, 2013; Acharya et al, 2013; Bahadur & Pathak, 2012; Devkar et al, 2014; Gaba et al, 2019; Gao et al, 2006; Haider et al, 2018; Jani et al, 2019; Patel, Patel, et al, 2013; Praveen et al, 2019; Ramreddy & Janapareddi, 2019; Sawant et al, 2016; Shah et al, 2015; Shah et al, 2021; Sood et al, 2014; Tzeyung et al, 2019; Upadhyay et al, 2017). In a more extensive study, porcine olfactory epithelium mounted in a vertical Franz diffusion chamber showed tissue damage that was greater after exposure to an equal number of 20, than 100, than 200 nm chitosan‐coated polystyrene particles (Mistry et al, 2015).…”