A new 3D printing technique could one-day yield more personalized treatments for those suffering from vascular diseases like hypertension.
A team of engineers from the University of Colorado Boulder has created a new method to 3D print while maintaining localized control of an object’s firmness, with the ultimate goal of 3D printing artificial arteries and organ tissue.
Yonghui Ding, a postdoctoral researcher in Mechanical Engineering and the lead author of the study, explained in an interview with R&D Magazine that 3D printing might fill a large need for artificial tissues and organs.
“Right now there is a huge need for artificial tissues,” Ding said. “Each day about 20 people die in the U.S. while they are waiting for a transplant because there is no donor.
“So I think 3D printing is a real promising way to go to create this artificial tissue and eventually we hope one day doctors can print personalized 3D printed tissues for patients,” he added.
According to the study, engineering an extracellular microenvironment that provides the level of mechanical, structural, and biochemical heterogeneity found in native tissues is of great interest for tissue and organ replacement, drug screening, and disease modeling.
Ding said that 3D printing has proven to be the cheapest and most effective method to achieve this goal.
“Right now a lot of people are trying to use 3D printing and different manufacturing technologies to fabricate the artificial tissue and organs,” Ding said. “Based on traditional fabrication techniques it is very difficult to create this very complicated and personalized structure.”
The new layer-by-layer printing technique features fine-grain, programmable control over the object’s rigidity, enabling researchers to mimic the complex geometry of blood vessels that are highly structure but need to remain pliable.
The researchers sought to add independent mechanical properties to 3D structures that mimic the body’s natural tissue, allowing them to create microstructures that can be customized for disease models.
Cardiovascular diseases often feature hardened blood vessels. However, it has proven difficult to engineer a solution for viable artery and tissue replacement.
To overcome these challenges, the researchers took advantage of oxygen’s role in setting the final form of a 3D-printed structure. While oxygen often causes incomplete curing, the researchers utilized a layer that allows a fixed rate of oxygen to permeate.
“A high-resolution micro-CLIP has enabled 3D printing of bioresorbable vascular devices with micro-scale resolution,” the authors write. “Controlled oxygen permeation can also be an asset for engineering mechanical properties in multi-stage photo-polymerizations.”
By allowing tight control over oxygen migration and its subsequent light exposure, the researchers are able to control which areas of an object are solidified to be harder or softer, while keeping the overall geometry the same.
The researchers demonstrated three versions of a simple structure—a top beam supported by two rods. The structures were identical in shape, size and materials but had been printed with three variations in rod rigidity—soft/soft, hard/soft and hard/hard. They found that the harder rods supported the top beam and the softer rods allowed the beam to full or partially collapse.
Next, the researchers repeated the demonstration with a small Chinese warrior figure. They printed the figure in a way where the outer layers remained hard, while the interior remained soft.
The 3D printer used is able to work with biomaterials as small as 10 microns. The researchers believe they can improve the capabilities even further in future studies.
“The next step is we are trying to put in living cells into the 3D printed material to try to create this living artificial tissue or artery,” Ding said.
The study was published in Nature Communications.
