Methods for producing engineered exosomes and other vesicle-like biological targets, including allowing a target vesicle-like structure to react and bind with immunomagnetic particles; capturing the immunomagnetic particle/vesicle complex by applying a magnetic field; further engineering the captured vesicles by surface modifying with additional active moieties or internally loading with active agents; and releasing the engineered vesicle-like structures, such as by photolytically cleaving a linkage between the particle and engineered vesicle-like structures, thereby releasing intact vesicle-like structures which can act as delivery vehicles for therapeutic treatments.