Engineering Nanoparticles for Internalization and Transport in Pulmonary Epithelia

M.D. Golam Jakaria, S. Meenach
University of Rhode Island,
United States

Keywords: cell uptake, endocytosis, epithelial cells, cell membrane coated nanoparticle, nanoparticle transport


The objective of this study was to develop and evaluate NP with polymer, phospholipid, or cell membrane coatings for their ability to internalize in or transport across a pulmonary epithelial barrier. In recent years, nanoparticles (NP) have been developed for pulmonary drug delivery applications in order to achieve controlled, targeted delivery of drugs to the lungs. Manipulation of the size and surface properties of NP has made them a promising medium for improved drug delivery (1). Inhalation is a desirable route of administration, as properly designed NP will preferentially deposit in the alveolar region, which offers advantages including: large surface area for drug absorption, high access to the bloodstream, weak enzymatic activity, and avoidance of first pass metabolism (2). Despite increasing interest, minimal attention has been paid to the effect of the surface properties of NP in crossing pulmonary epithelial barriers. In one study, the effect of NP size and surface charge was investigated on their interaction with Caco-2 monolayers as a model of intestinal epithelial (3). In another study, cell membrane vesicles derived from cancer cells, or red blood cells were used as NP coatings to enhance targeted delivery of the NP (4). In this project, curcumin (CUR)-loaded NP were formulated using the biodegradable, pH-sensitive polymer acetalated dextran (Ac-Dex) (5, 6) and were coated with various compounds, including poly(vinyl alcohol) (PVA), a poly(ethylene glycol) derivative (VP5k), N-[1-(2,3-dioleoyloxy) propyl]-N,N,N-trimethylammonium (DOTAP), dipalmitoylphosphotidylcholine (DPPC), and A549 and H441 cell membranes, where PVA, VP5k, DOTAP, and DPPC exhibited neutral, stealth, cationic, and anionic properties, respectively. The potential of the NP to be uptaken into and/or cross a pulmonary epithelial barrier was evaluated using a H441-based monolayer model. The NP systems were approximately 200 nm in diameter and their surface charges varied based on their coatings. NP size and morphology were confirmed via SEM and the core-shell structure of the cell membrane-coated NP were confirmed using TEM. The stability of the NP in DI water, PBS, and cell media was evaluated via UV-vis spectroscopy. Prior to NP exposure, H441 monolayer integrity was confirmed via transepithelial electrical resistance. The trend for NP internalization into H441 cells was not impacted by NP concentration and internalization of the cell membrane-coated (A549 and H441) NP was a significantly higher than any other NP system. H441-coated NP were transported significantly more across the monolayer than A549-coated NP. In addition, internalization of positively-charged DOTAP NP was higher than the negatively-charged DPPC NP. Overall, there seems to be no direct correlation between NP internalization versus NP transport across H441 monolayer, indicating the need to evaluate transport efficiency (ratio of internalization to transport) of the NP. Ongoing studies include determining cell internalization pathways using a panel of pharmacological inhibitors to establish whether the variation in transport efficiency is due to different uptake and transport pathways. Overall, this work shows the importance in NP surface coatings in the design of systems capable of uptake and/or transport across pulmonary epithelial barriers for pulmonary drug delivery applications.