melted at a high temperature. The ink is sent through a small tube that builds the object by laying very thin layers of polymer on top of one another on a platform, like a bricklayer building a wall brick by brick. The polymer quickly solidifies, and the next layer is added until the desired object is completed. Fancier versions of 3-D printing can use more than one type of polymer. Scientists have been developing better polymers and testing combinations of polymers to suit their particular needs. For example, researchers can use a combination of polymer and nanoparticles to create electronicbased objects. Recently, scientists at Harvard University made miniature lithium batteries
using 3-D printing technology, allowing for a small enough battery to power miniature devices. Dentists have been using 3-D printing to make molds of patients’ mouths, and some industries use 3-D printing to make surgical instruments. Manufacturers have been using 3-D printing to copy pieces or parts that need to be replaced in an appliance and for making prototype models. Even though 3-D printing has been around for a while, what is new is its accessibility. For the price of $400 to $1,200, anyone can order a 3-D printer from Amazon.com to satisfy all their at-home 3-D printing needs. Staples is even offering classes on how to use 3-D printers, and it’s not the only company to do so. Beyond copying inanimate objects, there are some new uses for 3-D printing in the biotech industry—which is where things get dicey. Now, scientists are able to copy living tissue, such as a trachea or a bladder. They have even made a miniature liver and a synthetic ear that can pick up radio frequencies. In these cases, the 3-D printing ink has polymer in it, but it’s also made of cellular material. In many cases, the patient’s own stem cells are incorporated onto the polymer scaffold during the printing process. The object is then removed from the printing platform and allowed to grow in culture. Within the culture, the cells will replicate over the polymer, creating a 3-D object. This biomaterial is then placed within the patient, and if it has been built with the patient’s cells,
“AS CHRISTIANS, WE SHOULDN’T BE OPPOSED TO NEW TECHNOLOGIES. WE NEED TO DO SCIENTIFIC INQUIRY IN A PRINCIPLED WAY.” —DR. MICHAEL SLEASMAN there are no risks of rejection or graft-versus-host disease. Additionally, because these special cells are able to keep growing, organs such as the trachea can incorporate into the patient’s body. Thus far, scientists have not been able to make large solid organs. The closest they’ve gotten is a miniature version of a liver. However, despite its size, it functioned like a human liver, which means it could potentially be used to test drug toxicity. According to Nigel Cameron, president of the Center for Policy on Emerging Technologies, this brings up questions about whether, in the future, we will need human trials to test for drug toxicity when we can make synthetic organs instead. He points out this would have a ripple effect on the pharmaceutical industry, including potentially speeding up—or even doing away with—the Food and Drug Administration’s current approval process, which is notoriously sluggish and relies on several different human clinical trials before a drug goes to market. Scientists have successfully made synthetic hollow organs, like a trachea, bladder and synthetic skin, using a nanocomposite material as the scaffold and the patient’s bone marrow stem cells to grow a new organ. For example, a man who lost part of his trachea to cancer received a transplant made from this sort of technology. 3-D printing offers another way to create the scaffold and another way to seed the cells. Compared to other scaffolding technologies, 3-D printing offers smaller, more controllable pore sizes, which helps when growing cells on the scaffold. As Dr. Michael Sleasman of the Center for Bioethics and Human Dignity points out, being able to engineer tissue-based organs would do away with many of the ethical questions surrounding organ transplantation, including tissue rejection and determining who gets the limited supply. RELEVANTMAGAZINE.COM
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