The organs-on-chips, known in the scientific community as microphysiological systems (MPS), are synthetic replacements for human internals -- not just hearts and livers but also bone, cartilage, microvasculature, and other tissues. But the Harvard researchers crucially integrated sensors into their MPS's, which provide non-invasive, electronic readouts on structures within the body.

The Harvard researchers developed six different "inks" into a cardiac microphysiological device -- aka, a heart on a chip. The integrated sensors allowed them to bypass the typically work-intensive process of collecting data, which otherwise requires microscopy or high-speed photography. To prove the efficacy of the 3D-printed organ, they applied the MPS to study drug responses and the development of stem cell-derived cardiac tissue, as the Harvard team reported in their paper published in Nature. Using the integrated sensors, future scientists will be able to study tissue performance after they've been inserted.