Using MEMS chips to find a way to control heart disease

At Nanyang Technological University in Singapore, medical researchers are trying to use a newly developed micro-electromechanical system (MEMS) microfluidic chip to study the causes and prevention of cardiovascular diseases...

EETimes Florida reported that in the future, studying the causes and prevention methods of cardiovascular disease will not be limited to dissecting rats or culturing heart cells in petri dishes. At Nanyang Technological University in Singapore, medical researchers are trying to achieve this goal using a newly developed micro-electromechanical system (MEMS) microfluidic chip.

The chip simulates the exact blood flow in an artery when fat and cholesterol accumulate in plaques on the inner arterial wall. In living tissue, the resulting atherosclerosis restricts blood flow and can lead to a heart attack. The most amazing thing about this chip is that it can simulate the inflammatory response of heart and blood vessel cells, which can cut off blood supply. If these reactions can be inhibited, then heart disease will not occur.

In the experiment, the researchers first used artificial blood to perfect the flow channels through the microfluidic "vessels", and then used real blood to simulate the inflammatory response that needs to be eliminated to prevent heart attacks. Because the response of the cells lining the blood vessels can be closely observed on the chip, the research team claims that their method of modeling atherosclerosis is far superior to methods that use cultured cells or laboratory animals to simulate conditions.

The team hopes to learn how to modulate vasoconstriction through a variety of means to prevent or at least mitigate heart attacks. So far, the researchers' efforts have focused on the overall biomechanics of blood flow in the heart and accurately modeling the shape and geometry of the heart's blood vessels to pinpoint the causes of vasoconstriction.

The square-foot chip features two stacked chambers separated by a flexible polymer membrane to simulate conditions that lead to a heart attack. The bottom chamber contains compressed air, and the top chamber contains blood (or a blood-like test fluid). To accurately simulate a real heart, the researchers cultured endothelial cells from coronary veins to fill the fluid-filled chambers. The system operates by pumping air into the flexible, inflatable chamber, pushing on the membrane to simulate restricted blood flow in a blocked artery.

Simulate atherosclerosis on a chip and assess blood vessel narrowing and blood health before a heart attack. (Source: Han Wei Hou)

The researchers found that as blood vessel blockage increased, endothelial cells released a protein that causes atherosclerosis, and when simulated using real blood, accumulation of immune cells more quickly developed lipids that form artery-clogging plaques.

According to Han Weihou, who led the chip's development, the chip's accuracy in mimicking these well-known precursors to heart disease makes it an ideal device for testing new therapies.

The team detailed their findings in the papers, “ Atherosclerosis-on-a-Chip : A Tunable 3D Stenotic Blood Vessel Microdevice,” and a Jan. 2 article, “ A tunable microfluidic 3D stenosis model to study leukocyte-endothelial interactions in atherosclerosis .”