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" There are many things we&amp;#039;ve come to expect from our computer printers: photos, letters, greeting cards, maybe even glowing wallpaper someday. But muscle and bone? You wouldn&amp;#039;t have gone there until this week, when scientists at Carnegie Mellon announced they have developed a printer that outputs in &amp;quot;bio-ink&amp;quot;\u2014a 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 toprint 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. &amp;quot;We loaded the bio-inks and then printed square patterns of the bone bio-ink on a glass slide,&amp;quot; says Phillippi. &amp;quot;Then we placed the slide with the patterns in a dish with muscle-derived stem cells from adult mice. The cells growing on the bone bio-ink pattern began to exhibit characteristics of bone-like cells, and cells outside the pattern began to look like muscle cells.&amp;quot; The scientists use a software program, designed in-house, to create the patterns. &amp;quot;The inkjet is ideal for what we&amp;#039;re trying to do because it allows for precise control over size, shape and concentration of the bio-ink patterns,&amp;quot; says Phillippi. The team is currently developing a 3D printer that consists of multiple print heads and delivers gel-like proteins as well as growth factors to build 3D patterns layer-by-layer. The printed bio-ink patterns have applications in tissue regeneration, Phillippi insists, including using adult stem cells to treat tissue defects. &amp;quot;Through such a patterning approach, our vision is to heal patients with defects that span multiple tissue types using the patient&amp;#039;s own stem cells,&amp;quot; she says. \u2013Erin McCarthy "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/science/a1093/4205063/>