Advanced heart-on-a-chip

DailyTechInfo based on materials Phys.org : Heartbeat on a chip could improve pharmaceutical testsHere and below are images from the University of Michigan press release – VM.

This transparent cube is a chip that is activated by the forces of gravity and which very accurately imitates the human pulse, imitating the basic physical rhythms that determine the functioning of the human body. The device created by researchers from the University of Michigan belongs to a fairly large class of laboratories-on-a-chip, microfluidic devices that allow research and testing of drugs in the laboratory, and not in clinical settings.

The first area of application of the new device will be the testing of new drugs designed to combat diseases of the human cardiovascular system, in which the results of these tests strongly depend on the quality of blood flow simulation. "This device is a kind of bridge between a Petri dish and a living patient," says Shuichi Takayama, professor of bioengineering at the University of Michigan, "Living blood cells behave more naturally when they experience pulsating rhythms similar to those of the human body. By duplicating these rhythms within the chip, we will be able to produce more accurate laboratory tests than other static systems allow."

It is worth noting that this is not the first attempt to create a lab-on-a-chip capable of simulating a heartbeat. But previous similar installations were built on the basis of piston pumps, which are quite capricious, unreliable and take up a lot of space. The new device, which has no moving or rubbing parts, is able to work continuously for very long periods of time. In addition, an additional control input of the device allows you to adjust both the frequency of the simulated pulse and the volume of blood passing through the chip structure. A simple change in the pressure at the chip inlet will allow scientists to perform several different tests simultaneously or sequentially.

The structure of the device is based on a very intricate network of microscopic channels, capacitors and microswitches, which, under the influence of external pressure and the force of Earth's gravity, allow you to get any combination of pulse rate, internal pressure and volume of blood passing through the device. This, in turn, allows tests to be performed by simulating conditions in the organisms of various people, both healthy and affected by various diseases.

"All microfluidic circuits consist of a set of basic components, some of which work reliably only in the presence of negative pressure," says Takayama, "With the help of computer modeling and calculations on specialized software, we have developed a new design for all such elements. Now the role of negative pressure for their reliable operation is played by gravity. And the combination of lithography and photolithography methods allowed us to make chips from silicone rubber, the cost of which does not exceed a few cents."

In addition to its main function, the new chip can be used as a modulator that regulates and simulates other biorhythms of the human body, for example, the supply of hormonal signals. "For example, we can study the reaction of the liver to insulin by suddenly feeding a large dose through the blood," says Takayama, "But the whole point is that in natural conditions the liver receives large amounts of insulin from the pancreas in the form of a series of small doses. And our device will allow us to reproduce a more accurate model of the processes taking place in the human body."

Since the new heart-on-a-chip device is not used in humans, but only in laboratory studies, their use can be started without waiting for a bunch of permits and approvals from various regulatory organizations. In addition, the researchers do not plan to commercialize the technology they have developed, and will make it available to all interested parties in the near future.

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25.06.2015