Organ-on-a-chip platforms integrated with biosensors for precise monitoring of the cells and cellular microenvironment

Organs-on-chips (OoCs) are in vitro models that simulate the anatomical and physiological structure of human organs at the micro-scale level. With the advantages of miniaturization, low reagent consumption, and precise controllability, they exhibit great potential in the studies of human disease, development of new drugs, and personalized medicine. To achieve accurate control and record in OoCs, it is required to integrate biosensors for precisely monitoring cells (i.e., cellular metabolism, functions, and responses to stimuli) and cellular microenvironment. This review outlines the current advances of biosensors-integrated OoC platforms for various biomedical applications, including monitoring cells, monitoring cellular microenvironment and simultaneous monitoring cells and the conditions of their microenvironment. Furthermore, different types of biosensors integrated into the OoCs are compared thoroughly by discussing their working principles, integration techniques, key findings, advantages and disadvantages. In the end, the challenges and future perspectives in this field are critically discussed.