Cambridge University Department of Engineering
When physicians run out of treatment options they look to a nascent field known as bioengineering. Specialized scientists apply engineering principles to biological systems, opening up the possibility of creating new human tissue, organs, blood and even corneas such as the one shown here. Waiting lists for organ transplants continue to be lengthy so the race to save lives with bioengineered body parts is on. Here’s a look at some of the most notable achievements in recent years.
Fraunhofer Institute for Interfacial Engineering and Biotechnology
Producing small amounts of artificial skin to graft on patients and use for toxicity testing has been possible for years. Human skin cells are cultivated in the lab and then embedded in a collagen scaffold. In 2011, the Fraunhofer Institute for Interfacial Engineering and Biotechnology introduced a system that can rapidly manufacture two-layer artificial skin models. Their Tissue Factory has the capacity to make 5,000 skin sheets in a month.
Princeton University / Frank Wojciechowski
Reproducing 3-D biological structures, particularly the complex human ear, presents significant challenges for bioengineers. A team at Princeton University led by mechanical and aerospace engineering associate professor Michael McAlpine used 3-D printing technology to make a functional ear from calf cells and electronic materials. The ear that debuted in May 2013 is no mere replacement -- it can pick up radio frequencies well beyond the range that human ears normally detect.
Popular Science via Getty Images
Surgeon Anthony Atala directs the Wake Forest Institute for Regenerative Medicine and is known for growing new human cells, tissues and organs -- particularly ones that advance urology. Atala and his team’s bioengineered bladders succeeded in clinical trials. The bladders were constructed from patients’ cells that were grown over two months on a biodegradable scaffold and then implanted. Patients included children with spina bifida who risked kidney failure. It’s been several years since then and the results are positive. “These constructs appear to be doing well as patients get older and grow,” Atala told the NIH Record.
Massachusetts General Hospital/PNAS
Being able to make blood vessels in the lab from a patient’s own cells could mean better treatments for cardiovascular disease, kidney disease and diabetes. In 2011, the head of California-based Cytograft Tissue Engineering reported progress in a study where three end-stage kidney disease patients were implanted with blood vessels bioengineered in the lab. After eight months the grafts continued to work well, easing access to dialysis. Then this month a team at Massachusetts General Hospital found a way to encourage stem-like cells to develop into vascular precursor cells, a key step on the way to becoming blood vessel cells. They generated long-lasting blood vessels in living mice.
Ott Lab / Massachusetts General Hospital
Artificial heart devices have been surgically implanted since the 1980s, but no device has been able to replace the human heart as effectively as a healthy biological one. After all, a human heart pumps 35 million times in a single year. Recently scientists have made advances in adding more biological material to artificial heart devices. In May the French company Carmat prepared to test an artificial device containing cow heart tissue. At Massachusetts General Hospital, surgeon Harald C. Ott and his team are working on a bioartificial heart scaffold while MIT researchers recently printed functional heart tissue from rodent cells.
Wake Forest University Baptist Medical Center
Bioengineers are working on it, but the liver is one of the largest, most challenging organs to recreate. In 2010 bioengineers at Wake Forest University Baptist Medical Center grew miniature livers in the lab using decellularized animal livers for the structure and human cells. This month, a team from the Yokohama City University Graduate School of Medicine published results of a study where they reprogrammed human adult skin cells, added other cell types, and got them to grow into early-stage liver “buds.” Currently the scientists can produce about 100 of them, but the study’s lead author Takanori Takebe told the Wall Street Journal that even a partial liver would require tens of thousands.
Harvard Apparatus Regenerative Technology
In April, after an international team of surgeons spent nine hours operating on her at Children's Hospital of Illinois in Peoria, 32-month old Hannah Warren became the youngest patient to ever receive a bioengineered organ. Scientists had made a windpipe for her using her own bone marrow cells. Born without a trachea, she needed help breathing, eating, drinking and talking. Harvard Bioscience created the custom scaffold and bioreactor for the experimental procedure. Sadly Hannah died on July 7 due to complications from a more recent surgery on her esophagus. Despite the high risks, bioengineers say they will continue to move ahead.
When a ruptured or degenerating disc causes chronic back pain, treatment is limited. At worst, patients undergo surgery to fuse vertebrae together and then have limited flexibility. Over the past several years artificial discs have emerged as an alternative, but they can wear out as they work. In 2011, a research team from Cornell University bioengineered implants using gel and collagen seeded with rat cells that were then successfully placed into rat spines. This summer Duke bioengineers took things further, coming up with a gel mixture they think can help regenerate tissue when injected into the space between discs.
Little by little, bioengineered intestines are being grown in the lab to diagnose digestive disorders and to help patients born without a piece of intestine. In 2011, Cornell biological and environmental engineering assistant professor John March began collaborating with Pittsburgh-based pediatric surgeon David Hackam on a small artificial intestine using collagen and stem cells. Then last year in Switzerland, EPFL professor Martin Gijs led a project in the Laboratory of Microsystems to create a miniature intestinal wall from cultured epithelial cells and electronics called NutriChip to identify foods that cause inflammation. Scientists at Harvard’s Wyss Institute also made a “gut-on-a chip” to mimic the real thing using intestinal cells in a tiny silicon polymer device.
University of California, San Francisco
One in 10 American adults will have some level of chronic kidney disease, according to the Centers for Disease Control and Prevention. Currently around 600,000 patients in the U.S. have chronic kidney failure. Most rely on dialysis while a fraction of them actually get transplants. Scientists from the University of California, San Francisco are on a mission to create a sophisticated artificial kidney device made with human kidney cells, silicon nanofilters and powered by blood pressure. The project, led by UCSF nephrologist William Fissell and bioengineering professor Shuvo Roy, aims to begin testing the kidney device in 2017.
In many places, tongue piercings are the very emblem of the edgy and the hip who hang out at the local tattoo parlor. Soon they might be more than a fashion statement: they’ll give mobility to people confined by paralysis to wheelchairs.
A team at the Georgia Institute of Technology led by Jeonghee Kim and Maysam Ghovanloo, invented a wheelchair control that uses a headset and a barbell tongue piercing. The work appears in this week’s issue of Science Translational Medicine.
Right now people with tetraplegia -- paralysis of all four limbs -- have to control wheelchairs by sipping and puffing air. That system has some big drawbacks: the tubes have to be cleaned and if the patient has a respiratory problem, and many do, it’s less useful.
Other methods of control -– using brain signals, for instance, or eye movements -– have their own problems. Brian wave systems haven’t proven reliable enough yet and tracking eye movements requires a camera in front of the person’s face, which makes it difficult for the user to see where she’s going. Voice recognition won’t work well for many tetraplegics either, because many have weak voices.
The tongue piercing, or Tongue Drive System (TDS), works by changing the magnetic field around the user’s mouth with a tongue flick. The researchers built a headset that surrounded part of the face. The tongue piercing was a simple barbell-shaped magnet. The headset picked up the changes in the magnetic field of the barbell, with sensors just outside the cheeks. They then relayed information to an iPod the user carried. The iPod detected the tongue commands, and sent them to a powered wheelchair.
The technology was first demonstrated as a prototype at a conference last year. That version had a dental retainer that contained some of the sensors and transmitters. The one used in the new study omitted the retainer.
The researchers tested the technology in 23 able-bodied and 11 paralyzed participants. All received custom-made titanium barbell piercings. After just a half an hour of training, all 33 participants were able to use the TDS, and their performance improved over several weeks. They could play video games, dial phone numbers and drive a powered wheelchair through an obstacle course using only their tongues.
The system also works with computers, so users could move a cursor, which obviates the need for fancy eye-tracking equipment.
Promising as the technology is, there is still some work to be done to get it ready for prime time. Ghovanloo has a startup company, Bionic Sciences, which is working with Georgia Tech to make it a commercial reality. He told DNews that he hopes to do that within two years.
Photo: Dr. Maysam Ghovanloo with a participant from the clinical trial. Credit: Courtesay Maysam Ghovanloo, Georgia Institute of Technology