Researchers from the Stevens Institute of Technology in New Jersey are using computer modeling techniques to advance microfluidic-based 3D bioprinting, and they hope it may one day enable the fabrication of whole human organs.
Many of today’s state-of-the-art bioprinters are based on extrusion processes, in which bioinks are deposited through a nozzle to create tissue structures measuring around 200 microns.
A microfluidics-based bioprinter would instead work by precisely manipulating liquids through tiny channels and could print structures measuring only tens of microns in diameter. This is more akin to the single cell scale and would be what would be needed if we are ever going to make 3D printed organs a reality.
Robert Chang, an associate professor at Stevens’ Schaefer School of Engineering & Science who is leading the work, explains: “Scale is very important because it affects the biology of the organ. We operate at the scale of human cells, allowing us to imprint structures that mimic the biological characteristics we are trying to replicate.
Towards human organ transplants
Organ transplants can save the lives of people with serious illnesses, but there has always been a shortage of suitable donors. In the United States, there are currently more than 100,000 patients on the transplant waiting list, with about 17 deaths every day while waiting for a donor.
3D bioprinting technology has long been heralded as a potential solution to the problem, but the lack of technology development means we’re not quite there yet. As it stands, bioprinters are adept at making simple single-cell tissues and structures, but Chang and his team believe microfluidics can hold the key to engineering virtually any type of complex tissue. This includes entire vital organs and even printed skin directly over open wounds.
“Creating new organs on command and saving lives without the need for a human donor will be of immense benefit to healthcare,” Chang said. “However, achieving this goal is tricky because printing organs using bio-inks – hydrogels loaded with cultured cells – requires a degree of precise control over the geometry and size of the printed microfibers that printers Current 3D simply can’t achieve.”
In addition to allowing much smaller scales, a microfluidics-based process will also be compatible with multiple bio-inks. Each of these bio-inks could contain precursors for different cell types, so users could combine them into a single printed tissue structure. This is crucial for complex organs such as the liver and kidney, as they depend on a wide variety of cell types working in tandem to function.
Computer modeling of 3D bioprinting
Reducing the 3D bioprinting process to a few tens of microns is not an easy task and requires studying how various parameters such as flow velocity, channel structures and fluid dynamics affect the properties of printed tissue structures. . To do this, Chang and his team developed a computer model of a microfluidic printhead. The model allows them to fine-tune parameters and predict how they might affect the process without having to conduct tedious physical experiments.
Ahmadreza Zaeri, first author of the study, said: “Our computational model offers formula extraction that can be used to predict the various geometric parameters of fabricated structures extruded from the microfluidic channels.”
By simulating the results of real-world experiments, the team is now gaining a better understanding of how a variety of organ structures might be printed. The results will be used to develop multicellular bio-inks. Chang is also working on adapting microfluidic bioprinting to fabricate skin directly over wounds.
Further details of the work can be found in the article titled “Numerical analysis of the effects of microfluidic bioprinting parameters on geometric results in microfiber”.
This is certainly not the first time that microfluidic technology has made headlines in the additive manufacturing sector. Earlier this year, Phase inc.a North Carolina-based medical 3D printing startup, has partnered with Virginia Tech to advance the field of microfluidic 3D printing. Together, Phase and Virginia Tech will use the former’s proprietary LE3D printing technology to develop new microfluidic devices that will help researchers formulate new and improved medical treatments for conditions such as brain cancer.
Elsewhere, researchers from University of Bristol previously developed a new low-cost, open-source 3D printing process to produce microfluidic devices. Requiring only simple household equipment and a standard desktop 3D printer, and having been developed in free software, the researchers’ process reduces the cost and complexity of manufacturing microfluidics to make the field more accessible.
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The featured image shows BICO’s Bio X 3D bioprinter, an extrusion-based system. Photo via BICO.