Membrane Integrated liposome Synthesized by a Liposome Fusion-Induced Membrane Exchange

Biogenic extracellular vesicles (EVs) from mammalian cells and bacteria are assembled by lipid bilayer membrane with carried biologically active cargos such as proteins and mRNA, which received enormous attention due to their various potential applications, including immune therapy, drug delivery system, catalysis, liquid biopsy, microbial fuel cells, and so on. However, scanty EVs produced by biogenesis limited their applicability in the actual condition, and therefore new technologies to enlarge the production of EVs must be developed and remain the challenge. In this study, we created a novel method named LIME (liposome fusion-induced membrane exchange) to acquire a large quantity of biologically active vesicles, in which the excess lipid components fused into the cell’s membrane, thus promoting the process of EVs liberation. This method was first verified in gram-negative bacteria, Shewanella oneidensis MR-1 with c-type cytochrome complex (Cyts) on the outer-membrane and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine contained liposomes as the lipid donor were used. Interestingly, the significant difference in spectroscopy and heme staining between original liposomes and active membrane-integrated liposomes (MILs) revealed that the electrochemically active Cyts migrate from MR-1 outer-membrane to the liposome successfully. Moreover, MILs with Cyts enabled enhancing the current production from Escherichia coli K-12, demonstrating that the electron transfer activity of Cyts was preserved after the LIME process, and MILs showed massive potential as drug carriers, vaccine, and a tool for strains-crossed membrane proteins migration. Our approach indicates an all-new direction to produce artificial EVs with specific proteins and functions, which will significantly benefit the future development of EVs.