Scale-out production of extracellular vesicles derived from natural killer cells via mechanical stimulation in a seesaw-motion bioreactor for cancer therapy

Extracellular vesicles (EVs) derived from immune cells have shown great anti-cancer therapeutic potential. However, inefficiency in EV generation has considerably impeded the development of EV-based basic research and clinical translation. Here, we developed a seesaw-motion bioreactor (SMB) system by leveraging mechanical stimuli such as shear stress and turbulence for generating EVs with high quality and quantity from natural killer (NK) cells. Compared to EV production in traditional static culture (229 ± 74 particles per cell per day), SMB produced NK-92MI-derived EVs at a higher rate of 438 ± 50 particles per cell per day and yielded a total number of 2 × 10¹¹ EVs over two weeks via continuous dynamic fluidic culture. In addition, the EVs generated from NK-92MI cells in SMB shared a similar morphology, size distribution, and protein profile to EVs generated from traditional static culture. Most importantly, the NK-92MI-derived EVs in SMB were functionally active in killing melanoma and liver cancer cells in both 2D and 3D culture conditions in vitro, as well as in suppressing melanoma growth in vivo. We believe that SMB is an attractive approach to producing EVs with high quality and quantity; it can additionally enhance EV production from NK92-MI cells and promote both the basic and translational research of EVs.