Nanoneurotoxicity and Potential Nanotheranostics for Alzheimer's Disease

Alzheimer's disease (AD) is the most common form of senile dementia and it is characterized by cognitive, motor and memory impairments. AD neuropathology includes toxic biomarkers, such as Aβ amyloid protein buildup between neurons disrupting connections, tau protein fibrillization and neuronal demise. These biomarkers are exacerbated with exposure to environmental borne or man-made nanoparticles or engineered nanomaterials (ENMs) as these nanoparticles are becoming more widely adopted for industrial applications. Studies suggest a link between nanoparticle exposure and neurotoxic responses, thus suggesting a contribution to AD pathology. This review summarizes research in the field of nanoparticles in terms of neurotoxic changes in the nervous system, as well as its relation to AD pathology. Studies involving silver, silica, copper oxide and iron oxide nanoparticles in mice suggest ranging neurotoxic reactions, such as disrupted neural connections, neuroinflammation, neuron cell death, redox stress, impairment of the blood-brain barrier (BBB), decrease in motor performance, demyelination of axons, decrease in long-term potentiation (LTP) and damage to DNA and brain structures. This review also examines beneficial effects of certain nanoparticles as potential therapeutic or diagnostic tools for AD.