Circulatory system on a chip lets scientists mimic heartbeat

Jun 28, 2005

A tiny chip that mimics a circulatory system—right down to the rhythm of a human heart beat—could be an invaluable tool in understanding the causes of cardiovascular disease and developing drug therapies.
The system of tiny valves and channels on the chip mimic blood flow in the body, said biomedical engineering professor Shuichi Takayama, corresponding author of the paper, "Computer Controlled Microcirculatory Support System for Endothelial Cell Culture and Shearing," scheduled to appear in July in the journal Analytical Chemistry.

The design lets scientists study the fluid mechanical effects of blood flow (called shear stress) in certain cells that play a critical role in heart disease. The cells, called endothelial cells, line the inner walls of blood vessels. The changes in ECs caused when blood flows past them at different speeds and rhythms are at least partly responsible for fueling certain diseases—including cardiovascular disease.

Studying endothelial cells in a Petri dish is often ineffective because the test environment is static, like bath water, said Takayama, so the cells are not acting as they would in the body where they are exposed to flow, like in a river. But with the U-M system, scientists can adjust the flow through the channels on the chip so that the ECs think they are inside an artery or vein, or maybe even inside the blood vessels of a couch potato or a regular exerciser, Takayama said.

The system is also capable of mimicking the irregular, surging flow of blood pumped by the heart. A big question in the study of heart disease and cardiovascular research is how these endothelial cells sense and convert the fluid mechanical stresses associated with blood flowing past the cell into diseases, such as hardening of the arteries or thrombosis. Answering those questions will provide big clues to developing therapies to regulate ECs.

To study this question, scientists have developed systems that model the physiological flow conditions of blood in the body. However, existing model systems cannot perform multiple experiments, are not easily portable, consume large amounts of reagents and can become contaminated easily.

The U-M team's chip differs from others because the intricate system of pumps and channels lets researchers sustain high levels of shear stress on the cells for hours or days, with various patterns of flow similar to how endothelial cells in the body are exposed to changing shear stress levels caused when blood flows past the cell. The microfluidic valving and pumping system lets researchers perform different tests simultaneously in multiple channels on the same chip.

The flow capability is accomplished by blending old and new technology. The central feature is a pin system that was originally meant to be used as part of a device that helps the visually impaired read e-mail, Takayama said. The pins move up and down beneath the reader's fingertips to represent certain Braille letters, thus translating what appears on the computer screen.

In the U-M invention, the pins move up and down to plunge fluid through a system of tiny channels drilled into the chip. The pins function as the heart of the system and the channels as the vasculature. A software program acts as the brain of the system to control pin movement, or the heart beat, and regulates fluid flow patterns, or the pulse, through the vasculature. The chip with the EC-lined vasculature is assembled in three layers and sits on top of the pin system.

The project is a collaboration between the departments of biomedical engineering and cardiology, restorative sciences, and endodontics. Team members include Jonathan Song, Wei Gu, Nobuyuki Futai, Kristy Warner and Jacques Nor.

The Braille technology also has applications for artificial insemination.

Source: University of Michigan

Explore further: Collin Burns in 5.253 seconds sets Rubik's Cube time record (w/ Video)

Related Stories

Nepal quake: Nearly 1,400 dead, Everest shaken (Update)

3 hours ago

Tens of thousands of people were spending the night in the open under a chilly and thunderous sky after a powerful earthquake devastated Nepal on Saturday, killing nearly 1,400, collapsing modern houses and ...

Russian hackers read Obama emails, report says

3 hours ago

Emails to and from President Barack Obama were read by Russian hackers last year in a breach of the White House's unclassified computer system, The New York Times said Saturday.

Supermarkets welcome cold-comfort edge of F1 aerofoils

8 hours ago

UK-based Williams Advanced Engineering, the technology and engineering services business of the Williams Group, has collaborated with UK-based Aerofoil Energy to develop an aerodynamic device that can reduce ...

Public boarding school—the way to solve educational ills?

11 hours ago

Buffalo's chronically struggling school system is considering an idea gaining momentum in other cities: public boarding schools that put round-the-clock attention on students and away from such daunting problems as poverty, ...

Recommended for you

Bizarre 'platypus' dinosaur discovered

3 hours ago

Although closely related to the notorious carnivore Tyrannosaurus rex, a new lineage of dinosaur discovered in Chile is proving to be an evolutionary jigsaw puzzle, as it preferred to graze upon plants.

Is the universe a hologram?

4 hours ago

Describing the universe requires fewer dimensions than we might think. New calculations show that this may not just be a mathematical trick, but a fundamental feature of space itself.

Why be creative on social media?

6 hours ago

There are five motivators for creating novel content online, whether blog posts, shared news stories, images, photos, songs, videos or any of the other digital artifacts users of social media and social networking sites share ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.