Nano-Based Probes for the Brain Extracellular Environment

Abstract

The brain is our most complex organ and governs all physiological function, from cognition and emotion to movement and stress response. Much of the brain’s function is determined by complex interactions of cells within the brain parenchyma, the functional unit of brain tissue critical for supporting and protecting cells. In fact, trauma or disease to the brain parenchyma can result in a loss of cognitive function and, in severe cases, death (Bonkhoff et al., Brain Commun 3(2):fcab110, 2021; Szarka et al., Int J Mol Sci 20(13), 2019; Thal et al., J Cell Mol Med 12(5B):1848–62, 2008;Smith et al., eLife 6, 2017). Several studies have shown microstructural changes to the brain parenchyma resulting from a variety of injury and disease states, such as traumatic brain injury (TBI), Alzheimer’s and Parkinson’s diseases, depression, and aging (Ayad et al., Philos Trans R Soc Lond Ser B Biol Sci 374(1779):20180215, 2019). As a result, brain microstructure has garnered significant attention in recent years from scientists and engineers as a neurological and micromechanical sink – an unexplored frontier for disease progression and a critical barrier to therapeutic delivery in the brain.