摘要Organ-on-a-chip systems have been increasingly recognized as attractive platforms to assess toxicity and to develop new therapeutic agents.However,current organ-on-a-chip platforms are limited by a"single pot"design,which inevitably requires holistic analysis and limits parallel processing.Here,we developed a digital organ-on-a-chip by combining a micro well array with cellular microspheres,which significantly increased the parallelism over traditional organ-on-a-chip for drug develop-ment.Up to 127 uniform liver cancer microspheres in this digital organ-on-a-chip format served as individual analytical units,allowing for analysis with high consistency and quick response.Our platform displayed evident anti-cancer efficacy at a concentration of 10 μM for sorafenib,and had greater alignment than the"single pot"organ-on-a-chip with a previous in vivo study.In addition,this digital organ-on-a-chip demonstrated the treatment efficacy of natural killer cell-derived extracellular vesicles for liver cancer at 50 μg/mL.The successful development of this digital organ-on-a-chip platform provides high-parallelism and a low-variability analytical tool for toxicity assessment and the exploration of new anticancer modalities,thereby accelerating the joint endeavor to combat cancer.