Harvard University researchers have developed the first entirely 3D-printed organ-on-a-chip with integrated sensing. Their heart-on-a-chip was built by a fully automated, digital manufacturing procedure and can be quickly customized, allowing researchers to easily collect reliable data for short-term and long-term studies. This new approach may one day allow researchers to rapidly design organs-on-chips that match the properties of a specific disease or even an individual patient’s cells. Currently, these devices are built in clean rooms using a complex, multi-step lithographic process and collecting data requires microscopy or high-speed cameras. The Harvard team developed new printable inks for multi-material 3D printing and were able to automate the fabrication process while increasing the complexity of the devices. The researchers developed six different inks that integrated soft strain sensors within the micro-architecture of the tissue. In a single, continuous procedure, the team 3D printed those materials into a heart-on-a-chip with integrated sensors.