Encapsulating significant amounts of macromolecules into EVs is challenging, and no comprehensive method for achieving this has been established. Active loading techniques typically involve disrupting the vesicle bilayer to facilitate drug encapsulation, which is particularly important for incorporating drugs with relatively high molecular weights. Electroporation has become a common method for loading EVs with nucleic acid-based therapeutics, although the extent of its destructiveness and potential loss of biological material during the process are not fully understood. Similarly, sonication is used to temporarily destabilize the membrane to load EVs with biological substances. There is a need for simpler, passive methods to load macromolecules, such as therapeutic agents, into EVs without compromising their functions; and to effective methods for encapsulating and delivering of large macromolecules (e.g., mRNA larger than 4700 nucleotides) into cells.