Authored by Chuck Hull
Following up about Lake Nona Impact Forum presentation last Friday, 11/27, moderated by Walter Isaacson discussing with Chuck Hull and United Therapeutics’ CEO Martine Rothblatt, the presentation focused on updating the forum’s Medical Centric audience about our program for 3D printing implantable lungs. The presentation was very well received, with a standing ovation at the end.
Martine addressed the need, with up to 300,000 sufferers of end stage lung disease. She described the printed lung scaffold, and how lung cells that are perfused into the scaffold to bring it to life. These cells are produced from the patient’s own cells so there will be no rejection. This is contrasted with today’s donated lungs that require the patient to take anti-rejection medication, and the patient is more subject to lung infections. She also hit on her vision of a factory with the capacity to supply these many lungs, and the large number of 3D printers it will take to do this. She also touched briefly on the other projects she has for liver and for kidney.
I mostly discussed the lung scaffold 3D printer we have developed, and the challenges and innovations it took to go from a conventional 3D printer to one that can print with such fine detail over the dimensions of a full-size lung, and with a material softer than Jello. The architecture is upside down stereolithography, with a vat of photocurable bioink. Imaging is through a glass plate and a flexible membrane at the bottom of the vat, with Texas Instruments Digital Multimirror Devices, projected through a microscope lens for the small feature size. This tiny 4MP image is “scrolled” across the image plane with a new image at every pixel – this method essentially eliminates the possibility that stuck pixels can have holes or blockages in the lung structure. The image is scrolled in 28 bands to expose the lung scaffold cross-sections. This is done layer after thousands of layers to 3D print the entire scaffold.
For bioink development, UT focused on the required physical and biological properties and 3D Systems focused on printability. Eventually these two studies were brought together and the final bioink developed. The printed material, like actual lung tissue, is extremely soft. 3D printers usually depend on having harder materials when successive layers are formed. The fine detail of a lung will distort or break apart with conventional recoating, especially at very thin layers, so a new “low force re-coater” technology has been developed. Finally, there is no way our original standard STL format can cope with the huge amount of detailed structure and data in a lung. A new format was developed, based on combining the Scientific capability of Mathematica with a library and format developed by DreamWorks Animation called OpenVDB. That format was developed for feature film visual effects and animation. I call this new format “Science meets Hollywood to manufacture transplantable lungs,”
These and more technologies were developed to make 3D printed lung scaffolds possible, and twenty-four of these printers are now running at United Therapeutics’ R&D lab in Manchester, NH. To be clear transplantable lungs is still an R&D project with many steps to go, but the ability to print lots of full-size scaffolds is a very major step along the way and something for 3D’s regenerative medicine team in San Diego to celebrate.
Another thing from the presentation, I have been working with a film team to put together a documentary about 3D printing and my journey along the way. The film team extracted a short teaser from the documentary about the lung project, and this was shown at the start of our presentation. It was a great introduction and set the tone. When the documentary nears completion and introduction I’ll update with more details.
