Graduation Date
Summer 8-1-2025
Availability
Immediate Access
Submission Type
dissertation
Degree Name
PhD
Department
Pharmaceutics
School
School of Pharmacy
Committee Chair
Devika S Manickam
Committee Member
Wilson Meng
Committee Member
Peter Wildfong
Committee Member
Lauren O'Donnell
Committee Member
James Drennen, III
Abstract
Lipid nanoparticles (LNPs) have revolutionized drug delivery, particularly in the delivery of gene silencing siRNA to the liver (Onpattro) and COVID-19 mRNA vaccines (Pfizer-BioNTech, Moderna). It is no exaggeration to state that the LNP delivery technology has protected billions of vaccinated people against a severe COVID-19 infection and subsequent mortality. Despite extensive research on LNPs for hepatic and muscle delivery, their potential for brain drug delivery remains underexplored. Many neurological disorders lack effective treatments, making LNP-based approaches promising for crossing or targeting drug delivery to the blood-brain barrier (BBB). Brain endothelial cells (BECs), a key component of the BBB, play a critical role in maintaining neurovascular homeostasis. Their dysfunction contributes to various neurological diseases, making them attractive targets for therapeutic intervention. However, intravenously administered LNPs primarily accumulate in the liver due to plasma protein adsorption, with less than 1% reaching the BBB. To address this limitation, we propose re-engineering LNPs with ionic liquids (ILs) to modulate their biodistribution and increase brain targeting.
ILs are tunable biomaterials composed of cations and anions that are known to influence drug pharmacokinetics and pharmacodynamics. Their interactions with plasma proteins and blood cells can affect systemic distribution. By re-engineering LNPs with ILs, particularly choline trans-2-hexenoate, we aimed to reduce plasma protein binding and facilitate red blood cell (RBC)-mediated transport to the BBB. RBC hitchhiking, wherein nanoparticles adhere to RBC membranes, enables increased systemic circulation and delivery to distant organs. Given the brain’s high blood supply, IL-re-engineered LNPs may achieve increased BBB accumulation compared to uncoated/standard LNPs. Prior to re-engineering LNPs with ILs, our primary objective was to evaluate the capability of LNPs to efficiently encapsulate and deliver a small molecule. We chose small molecules as our initial model cargo due to their relatively simpler handling and characterization compared to larger biomolecules like nucleic acids and proteins. Additionally, we sought to determine whether LNPs could effectively deliver small molecules to BECs, a critical yet less-explored cellular target within the BBB. As a proof of concept, we specifically investigated the ability of LNPs to encapsulate and deliver adenosine triphosphate (ATP) to BECs, which could provide preliminary insights into their potential for drug delivery to CNS targets. Using the C12-200 ionizable lipid and helper lipids such as polyethylene glycol-dimyristoyl glycerol (PEG-DMG), we optimized LNP stability and serum compatibility. PEG-DMG played a key role in maintaining colloidal stability, while its inclusion with ATP improved LNP performance in serum. ATP-LNPs exhibited a 7.7- and 6.6-fold increase in uptake into normoxic and hypoxic BECs, respectively, demonstrating their potential as a novel CNS drug delivery system.
Our re-engineering approach included two strategies: (1) IL-incorporation by replacing PEG-lipids with ILs in the formulation and (2) IL-coating of standard LNPs. Both methods produced colloidally stable LNPs with morphologies similar to conventional formulations. IL-coated LNPs demonstrated superior uptake into mouse BECs and neurons while reducing plasma protein adsorption. IL-coated– as well as IL-incorporated LNPs were colloidally stable with morphologies similar to the standard LNPs. IL-coated LNPs showed superior uptake into mouse BECs and neurons and demonstrated reduced mouse plasma protein adsorption compared to the standard LNPs. These IL-coated LNPs demonstrated the ability to hitchhike on both mouse and human RBCs and significantly enhanced uptake in mouse BECs and mouse neurons compared to uncoated LNPs. Our results demonstrate the feasibility of modifying LNPs with ILs to promote enhanced RBC hitchhiking and these hitchhiked particles may subsequently show increased accumulation at the BBB. Manickam lab's future studies will focus on testing the in vivo disposition of these IL-LNPs.
Language
English
Recommended Citation
Khare, P. (2025). LIPID NANOPARTICLE-MEDIATED DRUG DELIVERY TO CNS TARGETS (Doctoral dissertation, Duquesne University). Retrieved from https://dsc.duq.edu/etd/2458