Abstract: The invention relates to liposomes, methods of producing liposomes, and methods of loading cell-derived liposomes with cargo molecules. The invention extends to such liposomes per se, and to the use of these liposomes as cellular delivery systems for the delivery of biologically and therapeutically active payload molecules, such as small molecules, RNAi molecules (e.g. siRNA), bioactive proteins, genome editing tools (e.g. Cas9) and drugs into cells for treating a range of disorders. The liposomes may also be used in a range of diagnostic and theranostic applications. The invention extends to pharmaceutical compositions comprising such liposomes, including populations of extracellular vesicles (EV), exosomes and to fusion proteins.