Bioengineers at the University of California-Berkeley have created an inch-long device that models human heart tissue and acts as a drug-screening tool for testing cardiovascular medications. This “heart-on-a-chip” is described in a study in the journal Scientific Reports.

The cardiac microphysiological system holds a network of pulsating cardiac muscle cells, derived from human-induced pluripotent stem cells, and is designed to be comparable to the geometry and spacing of connective tissue fiber in a human heart. Microfluidic channels on either side of the cell area act as models for blood vessels and replicate the exchange of nutrients and drugs with human tissue by diffusion. The heart cells begin to beat on their own at a normal physiological rate of 55–80 beats per minute within 24 hours of being loaded into the chamber.

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The system was tested with isoproterenol, E-4031, verapamil, and metoprolol in order to measure the heart tissue’s response to the drug compounds via change in the heart tissue’s beat rate. The responses following exposure were predictable, as the beat rate of the heart tissue increased from 55 to 124 beats per minute half an hour after exposure to isoproterenol.

Because nonhuman animal models often have a high failure rate in predicting human reactions to new drugs, this system could be a more reliable testing tool and may be adapted to model human genetic disorders or to screen for individual reactions to medications. The researchers are now evaluating if the system could be used to model multi-organ interactions.

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