Engineering liposomes using microfluidic devices to model cancer-derived extracellular vesicles (EV)

Abstract

Liposomes are synthetic multivalent nanoparticles that can transport a variety of cargos, from genetic material such as RNA, like the most recent Covid-19 vaccines, to proteins and other molecules of interest. This delivery system was inspired by the naturally occurring extracellular vesicles (EVs), which are derived from all types of cells, including cancer cells. It has been shown that EVs contribute to the process of metastasis by transporting pro tumor factors to different organs, setting the stage for cancer growth. However, studying EVs is a complicated task due to their poor yield when isolating them from cells. The objective is therefore to provide a reliable protocol to produce synthetic liposomes that will mimic the physicochemical parameters of cancerous EVs, particularly their Z-average (diameter) and Zeta Potential (surface charge). Liposomes were produced using a microfluidic device developed by Lopez (López et al., 2020). This chip uses Dean Flow Dynamics to control the mixing process of lipids and fabricate liposomes under rigorously controlled conditions. In order to further understand how liposomes are formed, a design of experiment (DoE) approach was used. Based on a Rotatable Central Composite Design, the experimental space involving the different factors that affect the Zeta Potential and Z-average of liposomes were explored. A series of models spanning a broad spectrum of size and Zeta Potential were obtained using Response Surface Methodology. This statistical approach has allowed us to successfully fabricate liposomes of the targeted size and Zeta Potential that mimic the naturally occurring cancer EVs that were previously characterized. Finally, a series of experiments were carried out to study the behavior of hepatocytes (liver cells) and fibroblasts (connective tissue) when exposed to liposomes mimicking the cancerous EVs. The liposome synthesis approach presented in this work has the potential to be further developed by loading the liposomes and creating a tailored delivery system, allowing to further study cell-to-cell communication and metastasis and act as an optimized delivery system.

Date	17 Aug 2022
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Vahé Nerguizian (Supervisor) & Julia Valdemarin Burnier (Co-supervisor)