LAYER-BY-LAYER NANOPARTICLES DESIGNED FOR DUAL BLOOD-BRAIN BARRIER AND GLIOMA TARGETING

Abstract BACKGROUND While biologically diverse, high grade gliomas (HGGs) have a dismal prognosis in both adults and children. Promising therapeutics have been identified for HGGs based on common genomic alterations and aberrant signaling pathways, but achieving effective drug exposure at the tumor site remains a challenge largely due to the blood-brain barrier (BBB). HYPOTHESIS: A tunable nanocarrier platform can improve nanoparticle delivery across the (BBB) and into glioma cells. METHODS We synthesized layer-by-layer nanoparticles by coating anionic, fluorescent liposomes with nanometers-thick layers of oppositely charged polyelectrolytes, creating a library of organic, nontoxic drug carriers with varied surface chemistries. We characterized the library using dynamic light scattering and quantified interactions with a range of pediatric and adult glioma cell lines using flow cytometry. We used intravital two-photon microscopy to quantify nanoparticle trafficking across the intact BBB through a cranial window in anesthetized mice. RESULTS Nanoparticle surface chemistry strongly influences cellular trafficking in vitro, with two polymers identified as particularly high-performing across brain tumors lines: poly-L-aspartic acid (semi-synthetic) and hyaluronic acid (natural polysaccharide). The addition of the angiopep-2 targeting moiety onto these polymers improved nanoparticle uptake into brain microvascular endothelial cells in vitro without abrogating tumor affinity. We developed a new algorithm to quantify permeability of fluorescent compounds across the BBB in vivo and validated our method by measuring dextran permeability at varied molecular weights. In our initial study in non-tumor-bearing mice (n=12), we successfully quantified nanoparticle permeability across the BBB. In this study, surface functionalization did not increase BBB permeability above the control nanoparticle, though it did improve nanoparticle half-life in circulation and may still impart a therapeutic benefit when loaded with drug. Additional investigations in orthotopic tumor-bearing mice are ongoing. In summary, we report the development of layer-by-layer nanocarriers as a modular drug delivery platform with therapeutic potential for gliomas.