Cadmium sulfide-induced toxicity in the cortex and cerebellum: In vitro and in vivo studies

Living organisms have an innate ability to regulate the synthesis of inorganic materials, such as bones and teeth in humans. Cadmium sulfide (CdS) can be utilized as a quantum dot that functions as a unique light-emitting semiconductor nanocrystal. The increased use in CdS has led to an increased inhalation and ingestion rate of CdS by humans which requires a broader appreciation for the acute and chronic toxicity of CdS. We investigated the toxic effects of CdS on cerebellar cell cultures and rat brain. We employed a ‘green synthesis’ biosynthesis process to obtain biocompatible material that can be used in living organisms, such as Viridibacillus arenosi K64. Nanocrystal formation was initiated by adding CdCl₂ (1 mM) to the cell cultures. Our in vitro results established that increased concentrations of CdS (0.1 μg/mL) lead to decreased cell viability as assessed using 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT), total antioxidant capacity (TAC), and total oxidant status (TOS). The in vivo studies showed that exposure to CdS (1 mg/kg) glial fibrillary acidic protein (GFAP) and 8-hydroxy-2' -deoxyguanosine (8-OHdG) were increased. Collectively, we describe a model system that addresses the process from the synthesis to the neurotoxicity assessment for CdS both in vitro and in vivo. These data will be beneficial in establishing a more comprehensive pathway for the understanding of quantum dot-induced neurotoxicity.