'Artery On Chip': 3D Printed Blood Vessels Could Unravel Secrets Of Strokes

Charles's background is mechanical engineering but was inspired to take up a PhD in biomedical engineering to create something with more human impact. His knowledge in fluid dynamics was invaluable when applied to studying blood flow in blood vessels.

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3D printed blood vessels on glass that mimic blood vessel anatomy and the fluid dynamics of blood flow could be an invaluable tool in studying the causes of stroke, new research from a University of Sydney team has found and it has already led to important insights. The technology, published in Advanced Materials , could also help test new medications tailored to patients with specific health conditions.

Cardiovascular disease is currently the leading cause of mortality in Australia , with one person losing their life from heart disease approximately every 12 minutes.

Although there are well established diagnosis methods for cardiovascular diseases, there is no method to predict early events that lead to blood clots in carotid arteries.

"We're not just printing blood vessels - we're printing hope for millions at risk of stroke worldwide. With continued support and collaboration, we aim to make personalised vascular medicine accessible to every patient who needs it," said PhD candidate Charles Zhao from the School of Biomedical Engineering, Faculty of Engineering.

Charles's background is mechanical engineering but was inspired to take up a PhD in biomedical engineering to create something with more human impact. His knowledge in fluid dynamics was invaluable when applied to studying blood flow in blood vessels.

The model re-creates anatomically accurate replicas of healthy and diseased areas of blood vessels. This includes delicate blood vessel anatomy, and dents and divots on the damaged lining of the blood vessel wall, a pathology commonly seen in stroke patients.

Researchers used CT scans of stroke patients as blueprints to create mini models, shrinking the original carotid artery 3D model to 200 to 300 micrometers. A full-sized carotid artery is 5 to 7 mm.

The researchers were also able to 'shrink' the manufacturing time from 10 hours to two hours.

Traditional 3D printing moulds use resin, which is time consuming and has a high error rate. But the researchers developed a new method that uses glass slides as a base.

From a distance, the blood vessels look like delicate engravings on glass.

"When it comes to heart attack and stroke diagnosis, speed and accuracy is key," says Charles who is the first graduate student and founding member of the Ju Mechanobiology and Biomechanics Laboratory (MBL) .

"Clinicians typically have an approximately 12-hour decision-making window after symptom onset."

'Physical twin' of patient blood vessels

The 'artery on a chip' method successfully mimicked the physical appearance of blood vessels, and blood flow simulations generated similar fluid dynamics and movement of natural blood flow.

This was the standout moment, because the researchers said the biggest challenge in this field was re-creating the fluid dynamics of blood inside blood vessels. This detail is crucial because in people at risk of heart disease, blood is more viscous, which impacts how it flows through vessels.

"This is the first-of-its-kind bioengineering endeavour in Australia, and our work is aiming to solve two crucial gaps in heart disease diagnosis and prevention, without animal testing," said Dr Zihao Wang, the postdoctoral chief engineer of MBL group.

"There is still a lot we don't understand about the inside of our blood vessels and what creates the cascade of events that lead to blood clots, and there are currently no bespoke testing platforms that can be tailored for patients. No two patients are biologically identical, and everyone has differences in their blood vessel structure and blood, influencing their risk of blood clot disease and their treatment options."

During testing, the researchers were able to witness, in real time and under the microscope, blood clot formation and the behaviour of platelets which area crucial component involved in blood clotting that could lead to a stroke.

The technology revealed that the friction and force created by blood flow moving against the lining of the blood vessels played a huge part in platelet movement, that regulates clotting. This occurs during high blood pressure and atherosclerosis, a disease of the arteries.

In areas where there were high levels of stress placed on the blood vessels, the researchers found there were 7 to 10 times more platelet movement.