3D printing seems like something out of a science fiction book. ‘Just imagine it and it’s there!’ The 3D printing technology has given people the ability to print action figures, bottle openers, and even a working gun. Although most of these are just tacky bits of plastic you could just as easily order from Amazon, there have been some recent developments in 3D printing that could change the medical industry for ever: 3D printed bones. Printing bones could give people access to lives they could never have lived before, bone cancer patients could replace cancerous bones, trauma patients could go all natural instead of getting steel plates and arthritic adults could grow an entire new hip instead of replacing the old one with a steel socket. The act of printing bones is called bioprinting.
Bioprinting has been around for a while, the first patent being claimed in 2003 was granted in 2006. Bioprinting is the process of creating cell patterns in a confined space using 3D printing technologies, where cell function and viability are preserved within the printed construct. Basically, creating living tissues from just a cell slurry for the purposes of transplants or drug testing. In addition to being really cool, bioprinting could lead to the reduction or complete removal of animal testing for drugs and other chemicals.
“Bio-ink is a material made from living cells that behaves much like a liquid, allowing people to “print” it in order to create a desired shape. To make bio-ink, scientists create a slurry of cells that can be loaded into a cartridge and inserted into a specially designed printer, along with another cartridge containing a gel known as bio-paper.” – John J Manappallil
Historically, surgeons had to take a bone graft from the patient’s fibula and shape it to fit the new location. The problem is that the relatively straight fibula does not shape well to areas like the jaw or skull and removing bone from a patient’s leg causes trauma. With 3D printed bones, we could custom print a bone that would fit perfectly to the patient’s needs.
In the 3D bioprinting world, it has been difficult to print something that can sustain blood flow and therefore ‘live’ longer than a few days. 3D printers are not yet fine enough to print blood vessels and arteries which is what the body uses to keep tissues alive. However, with the invention of tiny ‘scaffolds’ (made up of a FDA approved plastic) in the bio printed material, scientists have been able to print bones and other pieces of cartilage that can stay alive for months before being successfully transplanted into living patients.
There are a few different methods for 3D printing and then growing bones. A more traditional way to 3D print living tissues, including bones, is to create a plastic ‘scaffolding’ that creates artificial pathways through the tissue so that the tissues can have access to oxygen and stay alive. The Johns Hopkins University has discovered that a mix of bone powder and PCL (a biodegradable polyester used in making polyurethane) is the best way to go. With studies showing that mice who have a 5, 30 and 70 percent bone powder mixture in their skull implants, lived longer and stood up to damages better than mice with a higher percentage of bone powder. To make sure that these PCL and bone powder mixtures held together, scientists added human fat derived stem cells to these scaffolds to give them the nutrients needed to grow bone.
The Advanced Materials and Bioengineering Research Centre (AMBER) at Trinity College, Dublin is using a different technique that might just change the way we grow bones all together. Bones, hard as they may be, are not solid like you might think. Rather, they are a porous material that is full of capillaries and connective tissue. Instead of trying to create artificial pathways with the miniature scaffoldings, these scientists are attempting to grow bone the way that our bodies naturally grow it, by starting with cartilage.
“Our bones begin life as a simpler cartilage template, which develops into a more complex tissue as we grow. So we have instead used bioprinting technology to fabricate mechanically reinforced cartilage templates in the shape of an adult bone, and demonstrated that these tissues develop into functional bone organs following implantation into the body.” – Professor Daniel Kelly of Trinity College’s School of Engineering
Bioprinting these cartilage templates means that the body naturally accepts the immature bone and helps it grow into a fully functioning porous bone. This is pretty exciting, considering the implications. We could completely replace metal bone replacements and all of the issues that comes with, and instead, grow natural bones that heal and function like any other bone.
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BitNavi is a blog conceived by Karl Motey in the heart of Silicon Valley, dedicated to emerging technologies and strategic business issues challenging the industry.
Kaya Lindsay is a local Santa Cruz contributor who spends her time globetrotting, surfing the web, and writing for the BitNavi team.
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