Researchers are using advanced bioprinting techniques to create 3D structures that closely resemble human tissue, opening the door to revolutionary biomanufacturing.
At the University of Virginia School of Engineering and Applied Science, a team of scientists has developed a groundbreaking approach that could pave the way for creating human-compatible organs as needed.
Liheng Cai, along with his Ph.D. student Jinchang Zhu, have successfully engineered biomaterials with tailored mechanical properties that closely mimic those of different human tissues.
Zhu mentioned, “This is a significant advancement compared to current bioprinting technologies.”
Their findings were published on July 13 in Nature Communications.
Their innovative bioprinting method, known as digital assembly of spherical particles (DASP), involves depositing biomaterial particles in a supporting matrix to construct 3D structures that provide a conducive environment for cell growth. This process is comparable to how “voxels,” the 3D equivalent of pixels, build 3D objects.
Zhu stated, “Our novel hydrogel particles serve as the very first functional voxel we have ever produced. These voxels, with precise control over their mechanical properties, could be essential building blocks for our future bioprinted constructs.”
One potential application of this technology is the printing of organoids, which are 3D cellular models that mimic human tissue and can be used to study disease progression in the quest for treatments.
These specially formulated polymer hydrogel particles, which imitate human tissue by adjusting the arrangement and chemical bonds of individual molecules, also contain real human cells.
According to Cai and Zhu, their bio-inks are less toxic and more biocompatible for cells compared to other hydrogels. Their “double network” hydrogels, made up of two intertwined molecular networks, are both mechanically robust and highly customizable to mimic the physical traits of human tissue.
In a previous publication in Advanced Functional Materials, Cai and Zhu introduced their DASP technology. Through lab experiments, they demonstrated a DASP-printed material that mimicked a pancreas’s function of releasing insulin in response to glucose stimulation.
However, the initial version, DASP 1.0, could only print fragile hydrogels with limited adjustability. In their latest work published in Nature Communications, they unveiled DASP 2.0, which incorporates double-network hydrogel bio-inks created using “click chemistry” for rapid molecular cross-linking.
One key factor enabling this progress was enhancements made to the team’s bioprinter, including the development of a multichannel nozzle to mix the hydrogel components on demand. Due to the rapid cross-linking process, it is impossible to pre-mix the components since they transform from liquid droplets to an elastic gel within seconds.
In previous trials, the team identified that creating droplets and quickly detaching them from the nozzle are crucial for mimicking the mechanical traits of the target human tissue, such as elasticity or stiffness.
Cai mentioned, “Accurate manipulation of viscoelastic voxels poses a significant challenge in soft matter science and 3D bioprinting.” He added, “We have established the groundwork for voxelated bioprinting. Once fully developed, DASP could have numerous applications, including artificial organ transplantation, disease and tissue modeling, drug screening, and potentially much more.”
This research was supported by various funding sources, including the National Science Foundation, UVA LaunchPad for Diabetes, UVA Coulter Center for Translational Research, Juvenile Diabetes Research Foundation, Virginia’s Commonwealth Health Research Board, and the UVA Center for Advanced Biomanufacturing.
