The invention includes systems, methods, and compositions for designing secreted fusogenic ectosome vesicles, or gectosomes, that selectively encapsulate specific target proteins, nucleic acids and/or other small molecules in a predetermined manner. These engineered gectosomes can be used to deliver desired cargos to receipt cells in vitro, ex vivo, or in vivo and may further reprogram target cellular phenotypes in a dose-dependent manner, as well as perform genome editing functions, among others.