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"Inkjet" printer helps organize stem cells
2006-12-11
An "inkjet"-style printer for stem cells may help scientists put the precious master cells to good use, U.S. researchers said on Sunday. A team of bioengineers at Carnegie Mellon University's Robotics Institute in Pittsburgh joined forces with stem cell biologists at the University of Pittsburgh School of Medicine to create the system, which they eventually hope will help them make stem cells grow into complex tissues. Stem cells are like the raw clay of the body, undifferentiated into specific tissue types such as brain cells, skin cells or liver cells. Doctors hope they hold the key to a whole range of regenerative therapies, but they are tricky to find and to work with. And it is not always easy to get them to mature into the desired cells. Tissue is complex, made up of a variety of different types of cells, and they must be layered together in the right pattern to work properly. Julie Jadlowiec Phillippi of Carnegie Mellon and her colleagues worked with mouse stem cells, so-called adult stem cells, meaning they are partly down the route of development. These particular stem cells were muscle-derived stem cells, destined to become a variety of bone and muscle cells, she told a meeting of the American Society for Cell Biology in San Diego. To get stem cells to differentiate, or develop into desired cell types, scientists use proteins called growth factors and other nurturing proteins. Each cell type requires a different protein recipe to nudge it down the right path. The Pittsburgh team came up with a system to make the cells develop into a useful pattern that resembles the complex pattern of cells seen in real bone. "It's a glass slide 1 inch by 1 inch, (2.54 cm by 2.54 cm)," Jadlowiec Phillippi said in a telephone interview. They laid down a layer of nurturing proteins as a base, and then used a robotic inkjet-style machine to squirt tiny quantities of various proteins down on top, in a specific pattern. "It is like laying ink on paper," she said. "It's a blueprint for cells to live and grow and differentiate with." Then the stem cells are placed on top of this pattern to grow. "Depending on which pattern they are on top of, they become one lineage or another," Jadlowiec Phillippi said. The mouse cells began to grow into bone-type cells, she told the meeting. Those not grown on the protein pattern matured on their own into muscle-type cells, she said. "Now we are looking at making cartilage and fat cells," she said. The technique is a long way from being used on real human patients, she cautioned. "We don't fully understand what patterns we need to heal and injury with," she said. Teams at Pittsburgh have also used muscle-derived stem cells to repair diseased tissue in animals with Duchenne Muscular Dystrophy, heart failure and bone defects.
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