Researchers continue to refine 3D printing of human tissue, according to a new study that demonstrates an ability to defy gravity and keep bioink layers in place as they cure. File Photo by Sergi Lopez Roig/Shutterstock
Feb. 16 (UPI) -- A new approach to 3D bioprinting has overcome the shortcomings associated with earlier versions of the technology, bringing the creation of human tissue and organs one step closer to reality, researchers at Carnegie Mellon University in Pittsburgh said Tuesday.
The approach, called Freefrom Reversible Embedding of Suspended Hydrogels, corrects problems caused by gravity in the bioinks used to "print" human tissue, according to the researchers in an article published by the journal APL Bioengineering.
Although 3D bioprinting has been studied for years as a "fabrication technique for [human] tissue engineering and regenerative medicine," its use has been limited "by the challenge of printing soft ... materials in air," co-author Daniel J. Shiwarski told UPI.
However, the new approach "has emerged as a revolutionary way to 3D bioprint a diverse range of biological and synthetic hydrogels" -- groups of substances with molecular structure, such as human tissue -- said Shiwarski, a post-doctoral fellow in the Regenerative Biomaterials Group at Carnegie Mellon.
"We can take patient-specific medical imaging data such as MRI or CT, and recreate the internal and external features of that tissue or organ from hydrogels like collagen to use as models for surgical planning or scaffolds for regenerative medicine" to induce tissue formation, he said.
Research into 3D bioprinting has grown rapidly in recent years as scientists seek to recreate the structure and function of complex biological systems from human tissues to entire organs, according to the researchers.
In the most popular 3D printing approach, a solution of biological material, or bioink, is loaded into a syringe pump and deposited in a layer-by-layer fashion to build an organ or piece of tissue.
However, gravity can distort the soft and liquid bioinks used in this method, making it challenging to fabricate functional adult-sized tissues and organs designed to supplement the limited donor supply for transplants.
The Freefrom Reversible Embedding of Suspended Hydrogels 3D bioprinting approach solves this problem by printing within a "support bath" that holds the bioinks in place until they are cured, according to Shiwarski.
Illustration by Adam Feinberg and Andrew Hudson/Carnegie Mellon University
The support bath also provides an environment during the printing process that maintains high cell viability, he and his colleagues said.
First developed in 2015, the approach has already been used in labs to induce stem cell growth and ventricle-like heart chambers composed of beating heart muscle cells.
Studies are underway to evaluate the technology in the 3D printing of skeletal muscle, according to the researchers.
Shiwarski said the technology has made progress. Researchers have bioprinted functional heart valves and contractile cardiac ventricles , but not anywhere near usability in medical treatment.
"At this point, we are still years away from having ... printed tissue in use clinically, [as] much work is still needed to both enhance our ability to generate billions of patient-specific cells to recreate a full adult organ," he said.