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that can be 3D printed. Somehow, the subtle shades of a medical image must
be deciphered they can be modeled into a computer design ile.
Gradations of white to gray to black don't provide enough information
to guide a 3D printer through the process of making a complicated body
part involving multiple cell types with a confusingly-similar appearance.
Computers are getting increasingly better at identifying subtle patterns in even
the slightest image gradations, and so there is plenty of hope. Turning grayscale
images into crisp and meaningful digital data remains a major area of medical
imaging research. Despite these limitations, however, medical researchers and
surgeons are managing to 3D print an amazing variety of accurate and highly
detailed artiicial body parts and surgical models.
The future
Thousands of people need new body parts if their original ones fail due to dis-
ease, a birth defect, or an accident. Fifty percent of people over 50 could use a
replacement spinal disc. Despite the overwhelming demand, replacement body
parts are hard to ind, and they cost a lot. According to the United Network
for Organ Sharing (UNOS), only 1 to 2 percent of the population manages to
die in a way that makes them potential organ donors.
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Even Steve Jobs, one
of the richest men in the world, had to wait for his replacement pancreas, and
he still died shortly thereafter.
If stem cells are the raw material of bioprinting, 3D printing complicated
vascular systems remains the tissue engineering equivalent of the 4-minute
mile. In 2004, researchers at the Medical University of South Carolina wrote
that “assembly of vascularized 3D soft organs remains a big challenge.”
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Several years later, this still holds true.
As eloquently described by an article in
Science
magazine,
Without a vascular system—a highway for delivering nutrients and
removing waste products—living cells on the inside of a 3D tissue
structure quickly die. Thin tissues grown from a few layers of cells
don't have this problem, as all of the cells have direct access to nutri-
ents and oxygen. Bioengineers have therefore explored 3D printing
as a way to prototype tissues containing large volumes of living
cells.
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