When Adam Feinberg tried to
figure out how to synthesize human tissue four years ago, his supplies
were prosaic: a kitchen blender, some gelatin packets from the
supermarket baking aisle, and a $2,000 3D printer.
“I had no
external funding when I started, so we did it kind of on the cheap,”
said Feinberg, 38, a biomedical engineer who runs a lab at Carnegie Mellon University in Pittsburgh.
In a paper published today in Science Advances,
Feinberg and his colleagues describe how they eventually refined the
technique to print structural replicas of the tissue of
arteries, brains, and other organs out of proteins like collagen and
fibrin. While the forms they created aren't functioning organs with
living cells, they could one day act as a scaffold on which to grow
actual tissues.
Adam Feinberg's lab at Carnegie Mellon uses 3D printing to try to replicate human tissues.
Source: Carnegie Mellon University College of Engineering
Doctors have already used 3D printing to support an infant's damaged windpipe, create a titanium jaw replacement, and synthesize tiny livers to test potential drug therapies.
Building functioning, custom organs ready for implant is still many
hurdles away. But the new research brings the futuristic promise of
bespoke tissues for medical therapies another step closer to reality.Feinberg’s fundamental
advance is figuring out how to keep the soft structures created by a
modified MakerBot 3D printer from collapsing under their own weight.
Unlike plastic, the normal material of a 3D printer, collagen won’t hold
its shape as it is being synthesized unless it has some support.
The
research team started thinking about how Jell-O molds can suspend
pieces of fruit in a sugary gel. They experimented with gelatin,
blending it into a slurry of fine particles. The slurry would support
the structure being built, layer by layer, while still allowing the
printer’s nozzle—modified with a syringe—to move freely. When the
printed object is complete, it would hold together on its own, and the
supporting gel could be melted away in water at body temperature.
Feinberg's lab modified an off-the-shelf MakerBot 3D printer to handle biological materials.
Source: Carnegie Mellon University College of Engineering
The
relative simplicity of the process means it will allow others to build
on the innovation, said Tommy Angelini, a University of Florida
professor whose lab recently published a similar method for engineering complex tissues. He wasn’t involved in Feinberg’s research. “It’s a very accessible, versatile method,” Angelini said.Cooking
up tissues that can be implanted into patients remains a challenge for
the future. “That’s going to happen eventually, but there’s still so
much fundamental science to be done,” Angelini said.
In the near
term, the new method of 3D printing might let doctors test medical
treatments on laboratory replicas of patients' own body parts.
Drug companies could use such models to test risky new drugs before
they're used in humans.
"Right now we have animal models—mice and
rats—and we have [human] clinical trials, and not a lot in between,"
Feinberg said. "You can potentially make basically a patient-specific
piece of heart muscle."
Feinberg’s research was supported by
grants from the National Institutes of Health and the National Science
Foundation. But the shoestring strategy he started with, hacking an
off-the-shelf printer and buying some gelatin packs, still informs how
his lab works. Though Carnegie Mellon has applied for a patent on the
support bath, his team is releasing information on how to modify the
MakerBot printer to handle biological materials under open-source
licenses. He has also demonstrated the bioprinting technique at a local
school, using chocolate frosting instead of collagen.
“We think
it’s a lot easier to use these less expensive machines,” Feinberg said.
“We can essentially modify it any way we need to make it work.”
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