There are many things we’ve come to expect from our computer
printers: photos, letters, greeting cards, maybe even glowing
wallpaper someday. But muscle and bone? You wouldn’t have gone
there until this week, when scientists at Carnegie Mellon
announced they have developed a printer that outputs in “bio-
ink”—a format they hope will pave the way for important
organization and growth of stem cells. In development for the
past eight years, the printer is similar to a conventional ink
jet, but with a custom-built nozzle designed to print patterns
more accurately. The machine prints in bio-ink, solutions of
hormones that alter cell behavior, to create a blueprint for
cells to grow and differentiate into the various types that
scientists want to create, according to Dr. Julie A. Phillippi.
She has worked on the project for about a year and a half. “We
loaded the bio-inks and then printed square patterns of the bone
bio-ink on a glass slide,” says Phillippi. “Then we placed the
slide with the patterns in a dish with