For the many people waiting for transplants, 3D-printed organs can't come soon enough. Researchers have been making strides towards developing the technology that would make it possible to simply print new organs for people who need them. Reporting in Advanced Materials, scientists have created a 'bio-ink' that can utilize cells from patients to bio-print human-sized airways, which enable blood vessels to grow into a synthetic tissue made for transplant. Any bio-printed organs would have to receive a blood supply once implanted, so this is a significant step towards the goal of 3D printed organs.
Chronic lung diseases are costly and there are few treatment options for many of them except for a lung transplant. But the supply of 'new' lungs is not enough to serve the needs of the patients that need them. If lung tissue can be grown on a scaffold, it may one day be possible to bio-print these organs.
In this study, the researchers created a synthetic material that contains cells and can be used in a 3D printer like ink is. This bio-ink was made with a natural material found in seaweed called alginate and extracellular matrix material that had been isolated from lung tissue.
"We started small by fabricating small tubes because this is a feature found in both airways and in the vasculature of the lung. By using our new bio-ink with stem cells isolated from patient airways, we were able to bio-print small airways which had multiple layers of cells and remained open over time," explained senior study author Darcy Wagner, an Associate Professor at Lund University.
While this study used the bi-oink to make airways, it can be adapted for other types of tissue.
"These next-generation bio-inks also support the maturation of the airway stem cells into multiple cell types found in adult human airways, which means that less cell types need to be printed, simplifying the nozzle numbers needed to print tissue made of multiple cell types," said Wagner. The resolution has to be improved to produce air sacs known as alveoli and more distal lung tissue, she noted.
"We hope that further technological improvements of available 3D printers and further bio-ink advances will allow for bioprinting at a higher resolution in order to engineer larger tissues which could be used for transplantation in the future. We still have a long way to go," she added.
The researchers also tested their new 3D-printed material in a mouse model of immunosuppression, which is meant to mimic what's seen in transplant patients. These mice tolerated the 3D-printed structures that were made, and new blood vessels were observed growing.
"The development of this new bio-ink is a significant step forward, but it is important to further validate the functionality of the small airways over time and to explore the feasibility of this approach in large animal models," noted first study author Martina De Santis.