At the University of Michigan, three children under 2 with tracheobronchomalacia had 3D printed devices implanted to open their airways and restore their breathing.
Professors Glenn Green and Scott Hollister were able to create and implant customized tracheal splints for each patient. The device was created directly from CT scans of their tracheas, integrating an image-based computer model with laser-based 3D printing to produce the splint.
The splint was sewn around the patient’s airways to expand the trachea and bronchus and give it a skeleton to aid proper growth. It is designed to be reabsorbed by the body over time. The growth of the airways were followed with CT and MRI scans, and it was shown to allow airway growth for all three patients.
The findings suggest that early treatment of tracheobronchomalacia may prevent complications of conventional treatment such as a tracheostomy, prolonged hospitalization, mechanical ventilation, cardiac and respiratory arrest, food malabsorption and discomfort. None of the devices implanted in this study have caused complications.
The bioresorable splints enabled the patients to come off of ventilators and ended their need for paralytics, narcotics and sedation. Researchers noted improvements in multiple organ systems. The patients were also relieved of immunodeficiency-causing proteins that prevented them from absorbing food so that they no longer needed intravenous therapy.
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MIT Technology Review
Harvard professor Jennifer Lewis has created a patch of tissue containing skin cells and biological structural material interwoven with blood-vessel-like structures using a 3-D printer and “disappearing” ink.
Lewis’s team created hollow, tube-like structures within a mesh of printed cells using an “ink” that liquefies as it cools. The tissue is built by the 3-D printer in layers. A gelatin-based ink acts as extracellular matrix—the structural mix of proteins and other biological molecules that surrounds cells in the body. Two other inks contained the gelatin material and either mouse or human skin cells. All these inks are viscous enough to maintain their structure after being laid down by the printer.
A third ink with counterintuitive behavior helped them create the hollow tubes. This ink has a Jell-O-like consistency at room temperature, but when cooled it liquefies. The team printed tracks of this ink amongst the others. After chilling the patch of printed tissue, the researchers applied a light vacuum to remove the special ink, leaving behind empty channels within the structure. Then cells that normally line blood vessels in the body can be infused into the channels.
The smallest channels printed were about 75 micrometers in diameter, which is much larger than the tiny capillaries that exchange nutrients and waste throughout the body. The hope is that the 3-D printing method will set the overall architecture of blood vessels within artificial tissue and then smaller blood vessels will develop along with the rest of the tissue.