Development of Cell-Derived Plasma Membrane Vesicles as a Nanoparticle Encapsulation and Delivery System

Developing non-invasive delivery platforms with a high level of structural and/or functional similarity to biological membranes is highly desirable to reduce toxicity and improve targeting capacity of nanoparticles. Numerous studies have investigated the impacts of physicochemical properties of engineered biomimetic nanoparticles on their interaction with cells, yet technical difficulties have led to the search for better biomimetics, including vesicles isolated directly from live cells. Cell-derived giant plasma membrane vesicles (GPMVs), in particular, offer a close approximation of the intact cell plasma membrane by maintaining the latter's compositional complexity, protein positioning in a fluid-mosaic pattern, and physical and mechanical properties. Thus, to overcome technical barriers of prior nanoparticle delivery approaches, we aimed to develop a novel method using GPMVs to encapsulate a variety of engineered nanoparticles, then use these core-shell, nanoparticle-GPMV vesicle structures to deliver cargo to other cells.

The GPMV system in this study was generated by chemically inducing vesiculation in A549 cells, a model human alveolar epithelial line. These cell-derived GPMVs retained encapsulated silica nanoparticles (50 nm diameter) for at least 48 hours at 37 °C. GPMVs showed nearly identical lipid and protein membrane profiles as the parental cell plasma membrane, with or without encapsulation of nanoparticles. Notably, GPMVs were readily endocytosed in the parental A549 cell line as well as the human monocytic THP-1 cell line. Higher cellular uptake levels were observed for GPMV-encapsulated nanoparticles compared to control groups, including free nanoparticles. Further, GPMVs delivered a variety of nanoparticles to parental cells with reduced cytotoxicity compared to free nanoparticles at concentrations that were otherwise significantly toxic.

We have introduced a novel technique to load nanoparticles within the cell plasma membrane during the GPMV vesiculation process. These GPMVs are capable of (a) encapsulating different types of nanoparticles (including larger and not highly-positively charged bodies that have been technically challenging cargoes) using a parental cell uptake technique, and (b) improving delivery of nanoparticles to cells without significant cytotoxicity. Ultimately, endogenous surface membrane proteins and lipids can optimize the physicochemical properties of cell membrane-derived vesicles, which could lead to highly effective cell membrane-based nanoparticle/drug delivery systems.