Embedding sensors into an entirely 3D-printed heart-on-a-chip, researchers hope to test the efficacy of pharmaceuticals on patients—without administering the drug to the patients at all.

Research jointly conducted by two separate Harvard institutions—the John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically Inspired Engineering—has led to an automated process which can rapidly fabricate a customizable heart-on-a-chip. The artificial organ, which can use cells from particular patients, employs embedded sensors to drastically simplify the work-intensive process of collecting data such as heart rate. This data can help researchers develop safer drugs—and might even help health professionals predict which drugs are right for individual patients.

The 3D-printed heart-on-a-chip employs embedded sensors to measure the strength and rate of heart beat. Image courtesy of SEAS.

The Technology of the Organ-on-a-Chip

An organ-on-a-chip (OC) is a type of artificial organ which is used to simulate the physiological response of an organ. These 3D microfluidic devices give a model to investigate the effect of drugs and toxins on human organs. Although the technology is still in its infancy, scientists hope that, one day, it will be possible to develop a precise in vitro model of the organs. They also believe that the technology may eliminate the need for experimenting with animals. Typically thousands of animals are killed to test a single drug and, unfortunately, the results cannot truly predict the drug effect on human organs.

These microfluidic devices can significantly speed up drug research and make the analysis of the test results much easier. The heart, the lung, kidney, artery, bone marrow, and skin are a number of the organs which have been previously modeled by an organ-on-a-chip.

Moreover, OC technology holds the potential for personalized medicine. Replicating the genetic properties of a specific patient onto a test device, scientists would be able to more accurately predict which drugs would be beneficial and find more successful solutions.

Screenshot courtesy of Johan U. Lind, Alex D. Valentine, Lori K. Sanders, and Leah Burrows via SEAS.

OC Technology with Embedded Sensors

Harvard’s OC is composed of a clear flexible polymer about the size of a memory stick. It includes some hollow tubes which are connected to the living cells. To provide the organ with a more realistic environment, researchers apply mechanical forces which model the breathing motion of lungs.

The researchers have previously 3D-printed heart tissue; however, the new technology integrates sensors into the chip. These sensors allow the scientists to monitor tissue response, such as the strength of a heart beat and beat rate at particular intervals as well as over a long period of time. Recording the readings of the sensors, researchers can easily analyze the effect of thousands of compounds on the tissue.

While experimenting with animals requires taking multiple blood samples and sometimes performing surgeries, the new OC gives instant feedback about the contractile strength of muscles and other responses to drugs and circumstances.

Testing a single drug through clinical studies is not only time-consuming but also very expensive. According to the Wyss Institute, the procedure may take years and cost more than $2 billion.

As Johan Ulrik Lind, a postdoctoral fellow involved in the study and the first author of the published paper, notes it is possible to replicate the genetic profile of a patient who suffers from a heart problem. To this end, scientists can extract stem cells out of the patient’s skin cells and use them to make cardiac cells. Now, the cardiac cells, which still attain the patient’s genetic characteristics, can be used in the heart-on-a-chip. In this way, an accurate model of the patient’s characteristics is obtained.

According to Kit Parker, co-author of the study and professor of Bioengineering and Applied Physics, the new microfabrication approach is a big stride in achieving in vitro tissue engineering, toxicology, and drug screening research.

The results of this study are published in the journal Nature Materials.

Featured image courtesy of Johan U. Lind, Alex D. Valentine, Lori K. Sanders, and Leah Burrows via SEAS.