At the University of Virginia, researchers developed a new voxel-based bioprinting technique. Voxels are 3D cubes that form basic blocks in computer graphics, similar to what pixels are for 2D, and have been popularized by games like Minecraft. The new technique involves printing discrete spherical stains of biotin (such as voxels) into a support matrix that then swells to fuse, forming a porous structure. Sticky biotints can be difficult to handle and print predictably, but this new technique helps solve this problem.
Bioprinting holds great promise as a method for 3D printing new tissues or even organs. However, there are many practical and technical hurdles that need to be overcome before reaching this point. Typically, the existing process involves printing a sticky biotin consisting of an array of biomaterial with suspended encapsulated cells. This is often achieved by printing the biotin as a filament coming out of the printer nozzle and then stacking the filaments layer by layer to form a structure.
One of the problems is that these sticky filaments are not easy to handle and it can be difficult to create a desired structure with this method. “It is very difficult to print biotinta particles because they are very sticky,” Liheng Cai, a researcher involved in the study, said in a press release. “Because biotins have the consistency of honey, it is difficult to control when and how they come off a printer nozzle. This becomes even more difficult when the bio ink particles are as small as the diameter of a thread. A second challenge is to manipulate each particle in its place to build a 3D structure. “
To do this, these researchers used the 3D pixels present in computer games as inspiration to build a bioprinted structure. His technique, called the Digital Assembly of Spherical Viscoelastic Bio-ink Particles (DASP), involves depositing a drop of biotin in a puree of gelatin microparticles. The support matrix allows researchers to place the “voxels” in precise places, to build the desired structure.
“Particles that keep a round shape need to be made as they come off the printer nozzle,” said Jinchang Zhu, another researcher involved in the study. “If the particles are too elastic, they will deform into a long, thin thread instead of being a ball.”
To date, researchers have used the technique to encapsulate pancreatic islets and have shown that the highly porous nature of the resulting printed construction allows the islets to react rapidly to glucose and rapidly release insulin. “We still can’t precisely define the properties of each particle like Minecraft does for every voxel,” Cai said. “But this technology is the first step toward 3D tissue printing with the complexity and organization needed for biomedical engineering, drug screening, and disease modeling.”
Watch a video of the technology:
Study a Advanced functional materials: Digital assembly of spherical particles of viscoelastic biotinta
