Engineering news
A team of researchers from Carnegie Mellon University printed tissue scaffolds out of collagen, the major structural protein in the human body, using the technique. Known as Freeform Reversible Embedding of Suspended Hydrogels (Fresh), it has allowed the researchers to overcome some of the huge challenges associated with existing 3D bioprinting methods.
With millions of patients worldwide in need of heart transplants, the need for replacement organs is immense, and new approaches to engineer artificial organs are needed. Over 6,200 people in the UK are currently waiting for an organ transplant, according to the NHS. Feinberg is working to solve this issue with a new generation of bioengineered organs that more closely replicates organ structures.
"What we've shown is that we can print pieces of the heart out of cells and collagen into parts that truly function, like a heart valve or a small beating ventricle," says Adam Feinberg, a professor of biomedical engineering at Carnegie Mellon. "By using MRI data of a human heart, we were able to accurately reproduce patient-specific anatomical structure and 3D bioprint collagen and human heart cells."
The new process could be revolutionary, said IMechE trustee Dr Helen Meese. “We’re going to be able to vastly improve the transplant process,” she said. “They’re getting closer and closer to mimicking human organs, but whether they’ll be able to transplant – we’re a bit further from that.”
Fresh innovation
Printing collagen is notoriously hard, said Andrew Hudson, co-first author on the paper. "It starts out as a fluid – so if you try to print this in air it just forms a puddle on your build platform. So we've developed a technique that prevents it from deforming."
The Fresh method allows collagen to be deposited layer-by-layer within a support bath of gel, giving it a chance to solidify in place before it is removed from the support bath. The support gel can be easily melted away by heating the gel from room temperature to body temperature after the print is complete. This way, the researchers can remove the support gel without damaging the printed structure made of collagen or cells.
The process is not limited to collagen, as a wide range of other soft gels including fibrin, alginate, and hyaluronic acid can also be printed using the technique. Importantly, the researchers also developed open-source designs so that nearly anyone, from medical labs to high school science classes, could build and have access to low-cost, high-performance 3D bioprinters.
“It would be a wonderful opportunity for medical schools and researchers around the world” said Dr Meese. She suggested that its accessibility could actually raise serious ethical issues, however – what if someone accidentally slices off a finger as they make dinner? Should they just print a new one? “This is where it gets difficult for engineers… it’s a lovely sci-fi thing to do, but I think the risk comes where you might open source it to the point where people would use it unethically. We have to be careful from the organ trading point of view.”
Fresh has potential applications in many aspects of regenerative medicine, from wound repair to organ bioengineering, but it is just one piece of a growing sector. "Really what we're talking about is the convergence of technologies," says Feinberg. "Not just what my lab does in bioprinting, but also from other labs and small companies in the areas of stem cell science, machine learning, and computer simulation, as well as new 3D bioprinting hardware and software."
This research could lead to 3D bioprinting with patients’ own cells in the future. “An advantage of this is we won’t get the sort of rejection from harvested organs that we would from a transplant, which would require the patient to be on long term drug therapies,” said Dr Meese.
This research appeared in Science.
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