The vast majority of drug candidates fail in clinical trials of safety and efficacy, with only 10% of drugs entering clinical stage trials achieving FDA approval. This incredibly high fail-rate indicates that the current pre-clinical testing practice of using animal models is insufficient to predict how the human body will respond to a drug. Therefore, there is a dire need to develop humanized models to validate pre-clinical candidate drugs. Recent advances in tissue engineering technology has led to “organ on a chip” microfluidic devices that can serve as a model of human organ function, however, these technologies have thus far been limited by a short length of culture time and modular integration of multiple organ systems. These inventors have created a revolutionary human microphysiological system that integrates up to seven organ systems.