MDNews - Central Pennsylvania

U SING SPECIALIZED MATERIALS in place of ink, 3-D printers take what is digital — mea- surements, angles and data points from detailed scans or renderings engineered with specially designed soft- ware — and create something physical. When this technology is used to create tissues and organs, it's called bio-printing. As a concept, 3-D printing may sound simple, but the road from the fi rst 3-D printer created in 1984 to printing a 3-D organ for transplant — something researchers hope to accomplish in the next few years — has had its share of hurdles. Building on Success Printing custom hand prosthetics, detailed heart renderings for surgical preparation or bioabsorbable airways to save young lives is obviously more complex than using a 3-D printer to make a whistle or toy. Yet these and countless other items have been created and used by clinicians to improve the lives of patients. The limits of custom implants, for example, are constantly being stretched. Detailed 3-D implantables can better serve patients because they are tailored to individual patient anatomy. Today, physicians are creating much more than customized crowns for teeth. Recently, physicians at Peking University reported suc- cessfully implanting a 3-D printed vertebra into a 12-year-old boy with Ewing's sarcoma, a rare cancer affecting the child's second vertebra. Using a special porous material, physicians created a replacement vertebra that they hope will naturally fuse with the body over time, creating a more secure bond. "There's never been more interest [in 3-D printing] than right now," says Andy Christensen, Vice President of Personalized Surgery and Medical Devices at 3D Systems, a company that specializes in 3-D printers, software and custom production. "The speed of production will continue to increase, and I think as it does, the cost will continue to decrease. We'll soon be reaching a point where many common orthopedic devices will actually be more effi cient to make from a cost standpoint using 3-D printing, which should open a whole new book." Around the world, researchers are using 3-D technology to create better implantable devices. At New York University's Langone Medical Center, physicians use 3-D technol- ogy to print replacement jawbones, and the FDA recently approved the fi rst 3-D printed products for use in facial reconstruction from Connecticut-based Oxford Performance Materials Inc. At 3D Systems, Christensen and his col- leagues are particularly excited about using additive metal manufacturing to simplify the creation of cost-effective implants — a production technique that takes a step back from the extreme personalization of one- off products but that has the potential to drastically reduce the cost of replacement joints and other implantables. "I think we'll continue to see an expansion of the types of things that 3-D printing can benefi t," Christensen says. "And I think many of those will not be boney-based, but soft-tissue based." Overcoming Obstacles On the road to printing implantable 3-D organs, researchers have worked to fi nd the optimal combination of advanced imaging techniques to gather useful data, software that allows specialists to fully analyze a structure layer by layer, and materials that have the fl exibility, durabil- ity, strength and detail needed to function inside the body. At the Wake Forest Institute for Regenerative Medicine in North Carolina, Director Anthony Atala, MD, presides over a team of researchers who routinely use 3-D printing to create tissues and organs for use in research, such as a bio- logic personnel defense project in which small-scale organ replicas are used to help develop immunizations and treatments to protect soldiers against potential chemical weapons. This process is now easier thanks to 3-D printing. "Before, we were making [tissues and organs] by hand, one at a time," Dr. Atala says. "The process was to take a small piece from a patient, about the size of a postage stamp. We would then be able to extend the cells outside the body, and we would then create three-dimensional molds that we would coat with the cells to create the constructs. "Now what we do is program the printer, and we are creating the tissues as we print them. We're printing the whole structure together, both the cells and scaffolding." Three-dimensional printing has allowed Dr. Atala's team to more easily make models larger or smaller, layer cells more precisely, and create reproducible results. His team discovered a method of help- ing maintain blood fl ow in transplanted, human-sized pig kidneys using cell seeding and a specialized antibody, bringing them one step closer to creating a transplantable human kidney. Another hurdle to creating a fully functional organ for implant was recently overcome when researchers from Harvard and Stanford universities, MIT, and the University of Sydney successfully printed an artificial network of blood vessels and capillaries capable of growing an endothelial lining. They did this by using a bio-ink that hardens as it cools to create a network, then suctioning the interior fl uid out, producing vessels. Sustainable vasculature to carry blood and nutrients to cells has been a long-standing barrier to developing truly functional organs. "Right now, this is a developing area, creating tissues and organs for patients," Dr. Atala says. "Being able to bio-print them will help us to deliver these technolo- gies to patients on a larger scale so that we can help repair missing or injured organs or tissues." What the Future Holds Organovo, a bio-printing company based in California, and companies elsewhere use 3-D printed tissue to more effectively test medications and other therapies. It's big business and will likely be the fi rst offi cially sanctioned use of bio-printed organs — but many, including Dr. Atala, look forward to the day when they can help patients even more directly. "Our hope," he says, "is to be able to use these bio-materials to place bio-printed tissues and organs in patients." ■ M D N E W S . CO M ■ MD NEWS Central Pennsylvania | 1 5

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