Among other common surgical procedures associated with cardiovascular disease – including coronary bypass surgery – include the use of vascular grafts.  For the procedure, repurposed blood vessels are surgically attached to obstructed or unhealthy blood vessels to permanently redirect the patient’s blood flow. While the procedure serves as a viable method, the limited supply of existing vessels from a patient’s own body can quickly lead to problems if there isn’t a proficient supply.

Recently, researchers at Shanghai University’s Rapid Manufacturing Engineering Center have developed a vascular graft that combines micro-imprinting and electro-spinning techniques – a process which uses an electrical charge to draw liquid inputs – to create sythetic blood vessels that can take the place of those that are repurposed from elsewhere in a patient’s or donor’s body.  The triple-layered structure of the resulting synthetic vessels is comprised of separate materials that possess mechanical strength and help promote new cell growth.  The resulting ‘3D printed’ blood vessels are also less-prone to having the same conditions as the vessels they are replacing…which ultimately leads into having to have the same surgical procedure repeated at a later time.

Images credit: J.J.

After the micro-imprinted synthetic blood vessels has been attached, they are able to carry out similar functions as natural blood vessels while also allowing new cells to grow around them.  After a duration of time, the cells create new vessels and the synthetic vessel is able to degrade away.

According to Yuanyuan Liu, an associate professor at the Rapid Manufacturing Engineering Center, the composite vascular grafts could be better candidates for blood vessel repair than a patient’s own existing blood vessels in the near future.  Liu’s team had previously worked with bone scaffolds, which are used to repair bone defects, before turning their attention to cardiovascular disease, and thus vascular grafts.

To create the ‘3D printed’ blood vessels, the structure of a vessel is mimicked by drawing liquid inputs from an electrical charge into microscopic fibers.  To increase the structural integrity of the vessel, researchers added a middle layer of material made out of poly-p-dioxanone, a biodegradable polymer commonly used in biomedical applications. After being combined during the electrospinning process, the three-layer structure is folded and attached to create a tube-like vessel that becomes the synthetic blood vessel.

Liu and her team then seeded the scaffold with rat fibroblast cells, which are ideal candidates because of their ease of cultivation and quick growth rate, to test the scaffold’s efficacy in promoting cellular expansion and integration. The researchers found that the cells on these composite scaffolds proliferated quickly, likely due to the functional amino and hydroxyl groups introduced by the chitosan.

Although the researchers are still a ways behind being able to test the new vessels in humans, they are optimistic about the future of their ‘3D printed blood vessel’ research.  Their next phase of research involves implanting the synthetic vessels into animal models to observe how the living cells and the synthetic vessels interact in the long-term.


Posted in 3D Printing Applications


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