Three Dimensional Printers in Medicine “Printing of a kidney or another human organ may sound like something out of a science fiction novel, but with the advancements in 3D printing technology, the idea may not be so far-fetched” (Thompson). Addictive manufacturing, or three dimensional printing, occurs when three dimensional solid objects are created from a digital model. Plastic, ceramic, glass, or metal can be combined into successive layers by using additive processes in order to print an object. This process is currently being used by companies such as Boeing, General Electric, and Honeywell to manufacture parts. In the past, three dimensional printing has been used for medical purposes, specifically to make prosthetic limbs, custom hearing aids, and dental fixtures. Due to the extreme success with 3D printing, medical researchers are now using the technology in more complex forms. They are making human tissue. These three dimensional printers, now called bio-printers, form human tissue by using a bio-ink that is made of living cell mixtures. “Basically, the bio-ink is used to build a 3D structure of cells, layer by layer, to form tissue” (Thompson). The goal for this technology is to be able to use the printed tissue to make organs. This will greatly increase the availability of organs needed for organ transplants. Already, a team of bioengineers have used this technology to print “3D patterns of blood vessel networks out of sugar that allow tissue to grow around them and then dissolve, leaving behind a hollowed-out vascular architecture. Once the sugar dissolves, the hollowed-out blood vessel pattern can rapidly be perfused with nutrient-rich fluid and oxygen to stop the tissue cells from dying" (Paddock). This has become one of the first steps to bring the medical community closer to being able to create new organs from the patient’s own cells. Unfortunately, as in everything in life, complications may arise. In this case, there is a possibility that the cells deep inside will begin to die. They lack a vascular system to deliver nutrients and oxygen and remove waste products. This is a common problem that may occur when trying to create organs with thicker tissue. Over the last couple of years, bio-printing and tissue engineering has improved greatly but, as of today, “it is still impossible to recreate the complex 3D blood vessel networks that are present in naturally grown organs” (Paddock). Bioengineers are currently hard at work trying to find a way to provide a decent vascular system to the organs they print. One of these attempts “is to grow the tissue and its vascular network layer by layer, but this has a significant problem in that the nutrient fluid can push open the seams between the layers” (Paddock). In Washington State University, bones are being manufactured by using three dimensional printing. The research team consists of a husband and wife that are hoping that this "breakthrough idea will change the future of medicine" (Estes). One day, three dimensional printing techniques will be used to create human organs and the blood vessels that connect them to the patient. But for now, the technology will be mostly confined to lab purposes only. Susmita Bose, the Washington State University bone printer, and her husband, Amit Bandyopadhyay, make up the team of researchers at Washington State University. Since the 1990s, they have been creating artificial bone-like materials. One aspect of their research has recently gained much attention. This would be the "successful in vitro growing actual bones around artificial scaffolds" (Estes). Although, the three dimensional printing cannot make full skeletons yet, the artificial bone scaffolds would prove extremely useful for doctors to use in order to repair injuries without the need of taking a bone graph from another part of the patient's body. This would also decrease the need to use a synthetic mesh material that can ultimately prove harmful for the patient. "We have tested it in small animal models and we have seen that bone grows over them very well," Bose told The Atlantic Wire. "We have also tested them with human bone cells and we've seen that bone will grow over them very well" (Estes). The scaffold is more of a bone-like ceramic that dissolves as new bone grows around it. It has no expected dangers for the patient as of now. Once the pair of researchers heard of the advances in successfully printing blood vessels, they began to see the idea of transplanting three dimensional printed organs into living patients actually become a real possibility for the upcoming years. They are expecting the human body to naturally reject artificial materials, as is expected. But there is a solution. Scientists are able to replicate the patient's cellular makeup by using controlled chemistry. Along with this, the scientists can add drugs to the cells and organs that can help the body accept the foreign artificial transplanted organs. Bose is "cautious about making an exact estimate, but she thinks that we could start seeing 3D printers in hospitals in the near future. 'Oftentimes we're excited with the scientific and technological findings but it is difficult to mimic nature. It could be five years; it could be 50. It is really very important for all of us to realize that bringing any scientific and technological innovation to real-life application requires interdisciplinary approach," she said (Estes). At Wake Forest University in North Carolina, medical researchers in regenerative medicine and the Armed Forces Institute for Regenerative Medicine have partnered their efforts to create cells by using the three dimensional printer. These cells will be deposited directly into a wound and therefore, help it heal faster. In addition, these medical researchers have become successful in creating kidney cells with the three dimensional printer. At Cornell University, three dimensional printing has helped bioengineers create knee cartilage, heart valves, and bone implants. One of the companies using bio-printers is Organovo. This San-Diego based company focuses on regenerative medicine. They print functional human tissue for medical research and regenerative therapies. "This is disruptive technology," said Mike Renard, Organovo's vice president of commercial operations. "It's always interesting and fun, but never easy" (Thompson). Shaochen Chen, a professor of nano-engineering at the University of California in San Diego often expresses his opinion regarding his expectations for the use of bio-printing technology. He believes that it will be at least ten years until scientists, bioengineers, and medical researchers can actually create completely functional organs. Even though it may be ten more years until the development of functional organs, bio-printing technology is still being used in many other ways. Some pharmaceutical companies have also been using bio-printing to conduct medical research. Chen said, "The technology may also have the potential to save the drug companies a lot of money because it could cut drug testing costs" (Thompson). In the past, two dimensional cell cultures were being used to test drugs during their development but those cultures do not depict real human tissue as accurately as the three dimensional printed tissue and can sometimes provide incorrect results. By using three dimensional printing to create three dimensional tissue, pharmaceutical companies have been able to produce more precise results. They can now "determine failed drugs early on before investing more money in development" (Thompson). According to a report from the President's Council on Science and Technology, "clinical trials are accounting for the largest percentage of the biopharmaceutical industry's budget for the research and development at $31.3 billion" (Thompson). Three dimensional printing, no doubt, helps minimize wasted expenses for the pharmaceutical companies. "It's very, very significant...It takes a lot of time and money developing a successful drug," Chen said. "I think this is a great idea and will save the pharmaceutical industry a lot of troubles ... It could help get drugs to market faster" (Thompson). An Australian company, Invetech, helped Organovo become the first company to launch a commercial three dimensional bio-printer. They named it the NovoGen MMX bio-printer. Originally, Organovo's plan was to sell the bio-printer to other companies. Once they realized its use for creating human tissue, Organovo decided to keep the bio-printer and use it to make tissues for drug companies for medical research and therapeutic applications. "'Generally, the drug business can benefit significantly from these 3D tissues ... There's plenty of evidence that their processes are basically broken. They are inefficient and highly suspect,' Renard said. 'There's a big problem and they are looking for a better solution.' Organovo, which trades on the OTC market, wants to be that solution" (Thompson). Since then, Organovo has made blood vessels, lung tissue, and recreated tumors using bio-printing. They are customizing tissue for other companies in every way possible. "We build custom tissue for them," Renard said. "They may have specific cell lines, disease areas of interests and they want a proprietary model for them ... we can make it" (Thompson). Eventually, three dimensional printers can be installed in hospitals. When a body part is needed, a doctor could simply send a scan to a specialist and that specialist would use the three dimensional printer and a computer-aided design file to provide a surgeon with the body part needed for the transplant. The surgeon will attach the needed organ to the patient and the patient will make a quick and safe recovery. That could be the future.

Works Cited
Estes, Adam C. "The Reality of 3D-Printed Body Parts." The Atlantic Wire. N.p., 02 Dec. 2011. Web. 11 Dec. 2012. <http://www.theatlanticwire.com/technology/2011/12/reality-3d-printed-body-parts/45649/>.
Paddock, Catharine. "Organ Regeneration Steps Closer With "3D Sugar Printing"" Medical News Today. MediLexicon International, 04 July 2012. Web. 11 Dec. 2012. <http://www.medicalnewstoday.com/articles/247344.php>.
Thompson, Cadie. "How 3D Printers Are Reshaping Medicine." CNBC.com. N.p., 12 Oct. 2012. Web. 11 Dec. 2012. <http://www.cnbc.com/id/49348354/How_3D_Printers_Are_Reshaping_Medicine>.