From butterfly wings to custom replacement body parts
Professor Alexander Seifalian
Inspired by butterfly wings, London researchers are designing and making custom-made replacement body parts. Professor Alexander Seifalian at University College London and his team are leading the effort to provide replacement organs using nano technology, 3D printing and the patient’s own stem cells.
In conjunction with the London Royal Free Hospital, noses, ears, tear ducts, blood vessels and trachea are being developed with a handful of patients already receiving the replacements under a compassionate use programme.
Professor Seifalian explains the innovative research behind the project began with studying butterfly wings. “The patterns of butterfly wings are different depending on the butterfly you are studying. When we crushed the wing we discovered a nano-particle and so we synthesized a similar chemical material. We found two types of materials—one that didn’t disappear, but stayed there forever and another that gradually disappeared,” he said. This approach enables the team to design scaffolds that are permanent or are gradually bio-absorbed, depending on the application. By studying the mechanical properties of various human body parts in cadavers, researchers can manufacture replacements that have the same mechanical properties.
The replacement body part process usually begins with a CT or MRI patient scan. In the case of a nose or an ear, facial pictures also are taken to help customise the design. These images are then converted via software to enable the 3D printing of a scaffold. The scaffold polymer material is patented. Seifalian said, “We have a nano-composite material based on nano-technology. We take the 3D printed scaffold, wash it, sterilize it and add the patient’s stem cells.” He added, “In some cases we make a scaffold that is honeycombed. When we manufacture it, we put in sugar and then dissolve the sugar to make lots of small holes, a honeycomb structure, and that’s the way the cells grow into the scaffold.”
FOR SOME REPLACEMENTS LIKE AN EAR OR A NOSE, IT IS STATIC, SITTING THERE AND DOING VIRTUALLY NOTHING; MORE COSMETIC. WITH INTERNAL ORGANS IT IS QUITE COMPLEX BECAUSE THEY HAVE TO FUNCTION.Professor Alexander Seifalian, at University College London
Originally the patient’s stem cells were harvested from bone marrow, a time consuming and painful process. The research team has moved to using the patient’s own fat as a stem cell source removed via liposuction and then concentrated. “This happens within three hours. The stem cells do not go out of the operating theatre. So this could be done in almost any hospital,” he said. For noses and ears, the scaffold is placed in a bioreactor filled with nutrients to encourage the stem cells to turn into cartilage.
Skin on another part of the patient’s body, such as an arm or forehead, is stretched by a small balloon inserted under the skin which is then inflated until is it loose enough to accommodate the scaffold. “Then we put the scaffold under the patient’s skin so their own skin can grow on it. In about seven to eight weeks, the skin has grown onto the scaffold and we can move it to the end site,” Seifalian said. He also noted that it is very important the scaffold has the same mechanical properties as the skin so it moves with the skin and will not extrude once implanted.
The opportunities for the replacement body part technology are vast, but Seifalian highlighted that some areas are easier than others. He said, “For some replacements like an ear or a nose, it is static, sitting there and doing virtually nothing; more cosmetic. With internal organs it is quite complex because they have to function.” However Professor Seifalian is exploring these applications as well. A UK coronary artery trial has just started, while a transcatheter delivered heart valve is in pre-clinical trials in France. He believes that complex organs such as kidneys and the liver are many years away. “We think there’s a huge potential for many simple organs, potentially almost off the shelf in any hospital,” he said.
Considering the hurdles to innovation, Professor Seifalian noted that academics have many demands on their time in addition to research: teaching, publishing papers, supervising theses, etc. Also costs can be prohibitive as grants usually only fund proof of concept, not development. He said, “For academics it can be difficult. We can do research and proof of concept, but taking it to a clinical trial is difficult and quite costly. GMP manufacturing, sterilized packaging, all the registry bodies…a lot of grant bodies don’t pay for costs in these areas. We also don’t have the expertise in these areas and to pay for the support is very difficult.”
Having surmounted many of these hurdles for several replacement body part applications using nano-technology 3D printed scaffolds, Professor Seifalian and his team are bringing the future forward.
Chondrogenic potential of bone marrow–derived mesenchymal stem cells on a novel, auricular-shaped, nanocomposite scaffold (2013) Available here: http://tej.sagepub.com/content/4/2041731413516782.full/
Surface Modification of Biomaterials: A Quest for Blood Compatibility (2012) Available here: http://www.hindawi.com/journals/ijbm/2012/707863/