One of the biggest challenges in tissue engineering is how to grow an organ quickly while ensuring it has enough blood supply. Natural blood vessels take time to grow, and without adequate nutrition new cells soon die.
Engineering new vessels
In an effort to solve this roadblock, a team has come up with a 3-D printed implant made of only sugar and silicone, with an inbuilt network of vessels.
If you want to grow replacement tissue quickly, you need to make sure new cells are fed - but this requires a network of blood vessels. Because these don't appear overnight, creating a network has been a major hurdle in growing anything larger in a short time period. One approach is to implant the new tissue and rely on the body's own vessel formation, but this frequently takes too long and cells can die waiting. This implant system comes with artificial channels to speed up growth, and maintain access to blood throughout the structure.
"We had a theory that maybe we shouldn't be waiting. We wondered if there were a way to implant a 3D printed construct where we could connect host arteries directly to the construct and get perfusion immediately. In this study, we are taking the first step toward applying an analogy from transplant surgery to 3D printed constructs we make in the lab."
How did they do it?
The development relies on simple chemistry. The researchers first formed a model of the vessels with sugar; similar to the intricate sugarwork produced by pastry chefs. This was done using an open source 3-D printer. They then covered this template with a silicone mould to form the overall implant, before cleverly dissolving the sugar vessels to leave a complex pattern of channels.
"What a surgeon needs in order to do transplant surgery isn't just a mass of cells; the surgeon needs a vessel inlet and an outlet that can be directly connected to arteries and veins"
The technology isn't quite ready yet, but when the implant was connected to a major artery in an animal mode, the artificial channels could withstand blood pressure and remained functional for a long period of time.
"This study provides a first step toward developing a transplant model for tissue engineering where the surgeon can directly connect arteries to an engineered tissue. In the future we aim to utilize a biodegradable material that also contains live cells next to these perfusable vessels for direct transplantation and monitoring long term."
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