Researcher(s)
- Ella Miller, Biomedical Engineering, University of North Carolina at Chapel Hill
Faculty Mentor(s)
- Emily Day, Biomedical Engineering, University of Delaware
Abstract
Endometriosis is a chronic inflammatory disease, affecting 1 in every 10 women, where endometrial-like tissue grows outside the uterus, causing persistent pain. Current treatments offer pain management rather than addressing the underlying inflammation. To specifically target inflammation in endometriotic lesions, I am evaluating biomimetic nanoparticles that are wrapped with plasma membranes derived from macrophages. The inflammation-targeting and immune evasion of these nanoparticles is enabled by various membrane-expressed proteins. Therefore, to maximize targeting efficiency and stability in biological environments, the coating procedure must be refined to ensure a majority of the nanoparticle surface is coated by the membrane. Towards this goal, I have extracted membranes from J774A.1 macrophages and coated nanoshells (NS), a model nanoparticle, at a 2:1 or 4:1 membrane-to-NS ratio using sonication and extrusion methods. The resultant macrophage membrane-wrapped NS (Mac-NS) were analyzed to determine the optimal wrapping ratio (2:1 or 4:1) and method (sonication or extrusion). The Mac-NS have been characterized using dynamic light scattering (DLS), spectrophotometry, transmission electron microscopy (TEM), and sodium dodecyl sulfate- poly(acrylamide) gel electrophoresis (SDS-PAGE). DLS shows that Mac-NS are ~15 nm larger in hydrodynamic diameter than unwrapped NS and have a more neutral zeta potential, independent of the wrapping ratio and coating method. Spectrophotometry confirmed that Mac-NS are stable in 137 mM NaCl (mimicking normal blood sodium levels) based on retention of their peak plasmon resonance, whereas uncoated NS exhibited a rapid decrease in extinction spectra upon NaCl exposure. TEM images show the presence of a membrane shell around the NS core and SDS-PAGE confirms membrane proteins are retained on Mac-NS after the wrapping process. While both sonication and extrusion can form membrane-coated NS, sonication is more amenable to large-scale manufacturing. We also found that the 4:1 membrane-to-NS ratio provides more consistent coating than the 2:1 ratio, through imaging and 7-day storage stability studies. Future studies will evaluate the ability of the optimized Mac-NS formulation (4:1 membrane-to-NS ratio, prepared by sonication) to selectively target endometriosis-associated inflammation in vitro and in vivo.