GETTING PAST THE GUARDS: A NOVEL LOOK INTO THE ENDOCYTIC MECHANISMS OF PARTICLES ACROSS THE BLOOD BRAIN BARRIER
Gauree Chendke, Tyler Brown, Samir Mitragotri.
University of California, Santa Barbara, Santa Barbara, CA.
Current treatments for neurodegenerative diseases, such as Alzheimer's and Parkinson's disease, still have not reached their full potential. With most of these treatments, the drug cannot reach the brain in high enough concentrations to provide a significant therapeutic effect. One major obstacle for treating diseases of the brain is the presence of the blood brain barrier (BBB), composed of a tightly connected network of endothelial cells. To overcome this barrier, nanoparticles can be used. Nanoparticles are ideal drug delivery agents since it is relatively easy to manipulate their size, flexibility, and surface chemistry. However, the ideal nanoparticle geometry for penetrating each biological barrier may vary. Therefore, we wish to investigate how the shape and size of nanoparticles affects the mechanism by which the nanoparticles cross the BBB. Using mouse brain endothelial cells (bEnd.3), we blocked different pathways of internalization to understand how a variety of fluorescently labeled nanoparticles of different shape and size are initially endocytosed. Sucrose, nystatin, and amiloride hydrochloride were each used to induce a different type of endocytosis, including clathrin-mediated endocytosis, caveolae-mediated endocytosis, and macropinocytosis, respectively. Particle internalization was assessed quantitatively with fluorescence spectroscopy and confirmed visually with confocal microscopy. Herein, we have outlined a platform of particle geometries for optimum internalization and hope to understand the effects of attaching targeting ligands, such as transferrin receptor antibodies, to the surface of the nanoparticles in the future.