Mimicking Cellular Metabolism in Artificial Cells: Universal Molecule Transport across the Membrane through Vesicle Fusion

Mass transport across cell membranes is a primary process for cellular metabolism. For this purpose, electrostatically mediated membrane fusion is exploited to transport various small molecules including glucose-6-phosphate, isopropyl beta-D-thiogalactoside, and macromolecules such as DNA plasmids from negatively charged large unilamellar vesicles (LUVs) to positively charged giant unilamellar vesicles (GUVs). After membrane fusion between these oppositely charged vesicles, molecules are transported into GUVs to trigger the NAD+ involved enzyme reaction, bacterial gene expression, and in vitro gene expression of green fluorescent protein from a DNA plasmid. The optimized charged lipid percentages are 10% for both positively charged GUVs and negatively charged LUVs to ensure the fusion process. The experimental results demonstrate a universal way for mass transport into the artificial cells through vesicle fusions, which paves a crucial step for the investigation of complicated cellular metabolism.