Iron oxide nanoparticles: a narrative review of in-depth analysis from neuroprotection to neurodegeneration

Air pollution is a major risk factor for neurological disorders. Both indoor and outdoor dusts comprise different types of iron oxides in the nano-scale range. Due to their small size and unique physico-chemical properties, iron oxide nanoparticles (IONPs) adopt the intracellular path to agglomerate inside the cell cytoplasm. Moreover, they can cross the blood–brain barrier to invade cortical tissues in the brain and impair neuronal functions. Hence, analysis of the effects of IONPs on the Central Nervous System (CNS) structure and functions is indispensable from medical perspective. A literature search was performed using three scientific databases: ScienceDirect, PubMed, and Google Scholar. Articles published till December, 2023 were screened for their relevancy. Analyses of the appropriate literature have revealed that IONPs are being employed in drug delivery systems and diagnosis of CNS-related ailments that favor neuroprotection. However, the inhalation of IONPs from air and other sources can lead to excessive accumulation of iron in the neuronal tissues, leading to a disturbance in neuronal signaling and augmenting the onset of neurodegenerative disorders. Therefore, it is essential to monitor and control the abundance of IONPs in the environment to combat adverse impacts on the human nervous system.