3D Printer Technology & Human Tissue Replication
The options available with 3D printing seem as broad as the human mind can imagine. A British patient was successfully implanted with a 3D-printed titanium pelvis. Surgeons in Wales have used 3D printing to rebuild parts of an injured motorcyclist’s face. A Dutch patient was transplanted with a 3D-printed titanium lower jaw. Now, researchers at The University of Texas Health Science Center at Houston (UTHealth) are also experimenting with the ground-breaking technology.
Picture a 3D printer as an industrial robot that can print a three-dimensional object using different materials. “Objects are printed from existing 3D models or electronic data,” explains W. Jim Zheng, Ph.D., associate professor and associate director of the Center for Computational Biomedicine at UTHealth School of Biomedical Informatics (SBMI). Models can be created with computer-aided design software or by using 3D scanners. 3D scanning analyzes and collects digital data on the appearance of a real object including shape, color, texture, and so forth. Then, you can manipulate objects via software by resizing and cutting them. From this data, you can produce 3D models of the scanned object.
To print a 3D object, the machine warms up the printing material to a liquid state. Then, it deposits the liquid printing material layer by layer onto a print plate. When one layer is ready and cooled down, a second layer is placed on top of the previous layer. These layers join together as they cool down. It can take several hours to several days to print out a model.
3D printing was first used in the 1980s in the manufacturing industry. “Many companies have now recognized this technology’s potential, and how it can transform their businesses to cater to the everyday consumer,” says Min Zhu, M.D., Ph.D., assistant professor at UTHealth School of Biomedical Informatics. “In-store manufacturing of goods can drastically reduce costs, while also providing consumers with quick and flexible access to replacement parts.”
Wal-Mart, for instance, is looking at using the technology to maintain inventory and cut its supply-chain costs.
By using a technology called “direct metal laser sintering,” General Electric will begin using 3D printing to manufacture fuel nozzles for jet engines which will be both lighter and more durable then nozzles manufactured by traditional techniques. “These fuel nozzles represent the greater potential of 3D printing for on-the-spot manufacturing of any type of product,” Zhu points out.
Even the average consumer now has access to 3D printing technology. UPS provides 3D printing services in its San Diego store. “Customers can print a customized iPhone case with a personal logo,” Zhu says.
When 3D printers become affordable, consumers will be able to buy them and develop their own prototypes. “3D printing will bring down the barrier between consumers and companies, as consumers’ ideas and feedbacks will be able to be quickly prototyped by 3D printing,” Zheng says. In return, consumers can just as quickly evaluate the prototypes, providing rapid turnaround in research and development.
3D printing and you
While 3D printing is ideal for replicating objects, it’s a little trickier to create customized objects for human beings. “Because people come in all shapes and sizes, it is difficult to produce uniquely-sized items and make products that fit individuals perfectly, such as gloves, belts and ear buds,” Zhu says. “The fit of an ear bud is always a challenge, for example, due to the variation of size and shape of human ears.”
Typically, if someone wanted a custom-built earphone, the process would cost thousands of dollars and could take a while to manufacture with the current mass production plants that excel in cranking out millions of one item quickly but are not good at customizing products for individuals.
But now a company called Normal — with a factory in New York City — provides a 3D solution in which users can download an app to their phones and take pictures of both ears using a coin as a point of reference so that the app can accurately measure. The app uses the 2D photos to create a 3D model, which can then be used to construct a custom ear bud for a consumer in two days.
3D printers lower the cost and reduce the time of making 3D objects that could only be made in factories before. “Now engineers, scientists and enthusiasts can release their creativity and make 3D objects in laboratories and even at home,” Zheng says.
Furthermore, attempts to print an entire human organ could revolutionize modern medicine if successful. “3D printers are changing the entire industry, from entertainment to health care,” Zheng says.
In the medical arena
Zhu and Zheng believe that 3D printing could very likely be the next revolution in the health care industry.
“Not only can 3D printers facilitate biomedical research, like what we do, but they can also advance life-improving medical technologies — such as 3D-printed orthopedic implants, 3D-printed body parts, including tissues and organs, or prosthetics, and 3D-printed medical devices,” Zheng says. “3D printing may also impact personalized medicine.”
At this time, 3D printers at UTHealth cannot print organs; they are limited to using a plastic compound that comes in a variety of colors. However, 3D printing of tissues is occurring in several labs globally that are experimenting with this process.
At SBMI’s Informatics Innovation (I2) Lab, graduate-level students, faculty and corporate and nonprofit partners are collaborating to develop cutting-edge technology solutions to real-world problems.
“The main purpose of having a 3D printer is to promote our students to think outside of the box in using this new technology,” Zhu says. “Our 3D printer should also help us prototype the product designs we create for our industry partners.”
To date, the lab has created some medical structures — such as parts of the human skeleton and molecular models. It’s also exploring other applications such as using the 3D scanner to scan the 3D model of a surgeon’s hand, and build a customized surgical device that fits the surgeon’s hand better.
“It is hard to tell what else we will do with our 3D printer in the future,” Zhu says. “It depends on the industry partnerships we form and the kind of projects we take on. We know that we have a good printer to get us started, but we may upgrade to a more advanced model as our projects grow.”
Zheng’s research group has used the 3D printer to create plastic protein and DNA models. “It’s more impressive to show students 3D models than just pictures of proteins and DNAs,” he says. “It’s also very useful in analyzing the human genome’s structure.”
Called bio-printing technology, 3D printers can now be used to grow human tissue for pharmaceutical research. “Some researchers are focusing on creating blood vessels and skin tissues,” Zhu says. “If a 3D printer can use a patient’s healthy cells to print out a new structure, it will reduce the risk of tissue rejection after organ transplantation.” But this is still in the early stages.
Currently, 3D organ printing is mostly used in virtual surgical planning. 3D printers can create a model of an internal structure from computed tomography (CT scan) or magnetic resonance imaging (MRI) data. This model can then be used for planning a complex surgery.
Certain parts of human bone and cartilages can be 3D printed using metal or polymer materials, which is similar to the process of 3D printing industrial products.
Dentistry is also using 3D printers to save time and enhance precision. 3D printers offer dentistry the ability to accurately and rapidly produce crowns, bridges, stone models and a range of orthodontic appliances.
Ron Karni, M.D., assistant professor of otorhinolaryngology-head and neck surgery at UTHealth Medical School, believes 3D printers will eventually be used to customize medical instrumentation to patient anatomy. “One of the core principles of minimally-invasive surgery is minimal disturbance of unaffected areas,” he says. For instance, he says a 3D printer might be coupled to the imaging data (say, from a CT scan) of a patient in order to create a customized oral retractor, allowing the surgeon to more easily access a tumor through the mouth. If a patient had a small mouth or narrow jaw, or had difficulty opening wide, customized retractors created by a 3D printer could be used in these challenging situations.
What the future holds
3D models are essentially patient data, in fact, the ultimate patient data. Ethical and safety concerns surrounding the protection of this private health information are plentiful. “Therefore, HIPAA regulations apply, and there may be implications on what’s considered private data,” Zhu points out. “Can 3D models from one patient be used to print an organ for another patient? We will have to answer these questions as the technology’s ability reaches the point where we can feasibly and affordably print human tissues for transplantation.”
As 3D printer technology progresses, Zhu believes that many patients with terminal illnesses such as cancer, or those suffering from traumatic injury may eventually be treated or cured.
Zhu muses on our 3D future. “If you want me to make a wild prediction for the next 100 years, companies may one day be able to use a robot to scan the broken pieces in a human body, print them out in real time and assemble them back into the body. When a car accident happens, a robot ambulance may come over and fix the patient on-site. Or maybe there will be no car accidents in the future, since cars will be driven by an automated guidance system.”