When it comes to news about wars, stories are often focussed on the mortality rate. Obviously, this is a very important part of wars and something which needs to be reported of. However, the world sometimes forgets about the wounded soldiers. The number of U.S. soldiers with serious injuries has increased, according to Michael Romanko, an official at the Armed Forces Institute of Regenerative Medicine (AFIRM) by the Department of Defence. The U.S. army therefore wants to try its luck with bioprinting.
The U.S. army currently invests in the technique and is investigating how it could help them to treat wounds. By printing skin cells on the patient, they hope to be able to recover wounds fully. Burns, which account for 10 to 30 percent of all war injuries, could potentially be recovered by bioprinting news layers of skin. The aforementioned AFIRM was therefore established in 2008. It is a network of universities, military laboratories and investigators and they focus on fields such as skin repair.
At the 2013 Experimental Biology conference in Boston, Organovo, a company specialised in bioprinting, presented the first fully cellular 3D bioprinted liver tissue.
“We have achieved excellent function in a fully cellular 3D human liver tissue. With Organovo’s 3D bioprinted liver tissues, we have demonstrated the power of bioprinting to create functional human tissue that replicates human biology better than what has come before. Not only can these tissues be a first step towards larger 3D liver, laboratory tests with these samples have the potential to be game changing for medical research. We believe these models will prove superior in their ability to provide predictive data for drug discovery and development, better than animal models or current cell models,” said Keith Murphy, Chairman and Chief Executive Officer at Organovo.
Cross-section of multi-cellular bioprinted human liver tissue
Key research features
Organovo managed to combine three key features that set their 3D tissues apart from 2D cell-culture models.
1. The tissues are not a monolayer of cells (approximately 20 cell layers thick)
2. The multi-cellular tissues closely reproduce the distinct cellular patterns found in native tissue.
3. The Organovo tissues are highly cellular, comprised of cells and the proteins those cells produce, without dependence on biomaterials or scaffold for 3-dimensionality. As Dr. Sharon Presnell, CTO and VP of R&D stated: “They actually look and feel like living tissue”.
Click here for more information about Organovo’s 3D Human Liver Tissue Model.
Scientists at the Cornell University have found a method that enables them to grow a new ear within days using a combination of 3D printing and living-cell gels. This new technique could help hundreds of children born with the … syndrome (missing an ear) to give them an ear that looks and feels biologically normal.
“This is such a win-win for both medicine and basic science, demonstrating what we can achieve when we work together,” said co-lead author Lawrence Bonassar, associate professor of biomedical engineering.
To make the ears, Bonassar and colleagues started with a digitized 3-D image of a human subject’s ear and converted the image into a digitized “solid” ear using a 3-D printer to assemble a mold. They injected the mold with collagen derived from rat tails, and then added 250 million cartilage cells from the ears of cows. This Cornell-developed, high-density gel is similar to the consistency of Jell-O when the mold is removed. The collagen served as a scaffold upon which cartilage could grow.
Today, the only reliable treating method is to take a piece of rib bone and carve and mold it into an ear shape before covering it with skin grafts. These scientists hope that this new technology will be less invasive for the patient and give a more natural look.
Now there is something new. The scientists at the Wake Forest Institute for Regenerative Medicine (WFIRM) have recently made advances in simplifying the printing process for creating implantable cartilage-constructs that could be used to help re-grow damaged cartilage in areas such as joints. The WFIRM scientists used a hybrid 3D printer which is a combination of an inkjet printer and an electro spinning machine.
The combination of these two technologies is the key to creating cartilage-constructs as it combines both synthetic (for strength) and natural (gel used to promote healthy cell growth) materials. The scientists used the electrospinning machine to generate an electrical current through polymer solution to create very fine fibers. The process allows the scientists to control the composition of the polymers, which coalesce into porous structures and allows the cells to integrate into the surrounding tissue.
“This is a proof of concept study and illustrates that a combination of materials and fabrication methods generates durable implantable constructs,” said James Yoo, M.D., Ph.D., Professor at the Wake Forest Institute for Regenerative Medicine, and an author on the study. “Other methods of fabrication, such as robotic systems, are currently being developed to further improve the production of implantable tissue constructs.”
Applying it in practice
Combined with a solution of healthy rabbit ear cells, the scientists tested their findings using layered flexible mats of electro spun polymer. These were deposited using the hybrid 3D printer. The constructs resulting out of the printing sessions were then stress-tested, they were found to be robust and still alive after one week of testing using variable weights. To see how these constructs would function/react in a living system, they were introduced into living mice in a controlled environment. All developments were analyzed for two, four and eight weeks. After eight weeks the constructs developed the structures and properties of that of elastic cartilage. This is very promising for use in human patients.
If you have heard of term bioprinting than you know that scientists are already capable of creating small samples of human tissue in the lab. The big problem at this point is that before they can make human sized organs, the scientists need to find a way to keep large quantities of the cells alive so they have enough to print entire organs.
To convince living cells to grow into things like liver tissue or heart tissue, cells need to get nutrients or else they die. The tissues in our bodies have blood vessels to solve this problem, but trying to 3D print a tiny empty space is not an easy job.
A network of sugar
To tackle this problem Jordan Miller found a way to make a model of the blood vessel network in a material that ultimately dissolves away. Sugar. To creat this network, Jordan used a Makerbot 3D printer to make this sugar. There were some modifications needed to be able to keep the sugar dry and intact and to stop the sugar extrusion very precisely. Because of the open-source network of Makerbot and RepRap the team was able to tackle both problems with a heated build platform and a Frosttruder. With these modifications and a lot of trial and error, the team now introduced a great way to work with 3D printed human tissue and we’re yet one step closer to the actual realization of printing human organs!
These two video’s show how this vessel network works and how it’s printed
Bioprinting is in its early days but the future looks very exciting. Using modified printer cartridges and extracted cells as the basis, bioprinting will make it possible to print full organs and other human parts on demand. Such a possibility will eventually wipe out the need for donor organs, which is a problem today considering the vast amount of patients in need of new organs.
This infographic created by PrinterInks (in collaboration with Organovo) shows where bio-printing is headed in the future: