New developments in the 3D printing of human tissue have been cropping up in the headlines with increasing frequency lately; in my opinion, bioprinting is one of the most exciting 3D printing applications in existence. It’s not as new as you may think, though; the technology has been in development for over a decade. Dr. Bradley Ringeisen, Head of the Bioenergy and Biofabrication Section for the chemistry division of the United States Naval Research Laboratory (NRL), is one of the pioneers of bioprinting, and he was recently recognized as the Department of Defense Scientist of the Quarter for the work he has been doing in the field since 2000.
If you’ve been following the latest developments in bioprinting, you’ll know that several companies and research organizations have stepped into the arena with new methods for printing cells, tissues, and even organs. While the methods vary from company to company, most bioprinting techniques involve the use of “inks” created from stem cells mixed with nutrient-fortified gels or liquids to print soft tissue. While printers have been developed specifically for the purpose of bioprinting, standard printers have also been used; it’s the same extruder-based process that the most common 3D printers use. Dr. Ringeisen, who began working for NRL as a post-doctoral associate before being hired full time in 2002, developed a very different method.
That method is known as Biological Laser Printing, or BioLP, and it’s been patented by the NRL, which, in its patent application, describes the technology as:
“A method for creating a microarray of proteins and other biomaterials that uses focused laser pulses to transfer material from a three layer target onto a receiving substrate. The transparent support layer allows a laser pulse to focus at its interface with the absorbant coating layer causing the biomaterial to be propelled to a specific location on the receiving substrate.”
Those biomaterials can be cell inks, gels or solids, as well as soil and sediment or biomolecules. Dr. Ringeisen was the first to print both mammalian and bacterial cells using the technology, and he has since developed it further by adding a laser absorption layer to protect the biomaterials from the lasers’ potentially damaging ultraviolet light.
“BioLP is unique because it does not use a traditional micro-tube or capillary-based printhead,” said Dr. Ringeisen. “Therefore, BioLP cannot clog and has been used to print a variety of materials….BioLP has also been used in conjunction with Navy-patented biodegradable biopapers that can be easily printed to and then stacked to create 3D tissue mimics. These biopapers have been created with a range of material properties that mimic soft and hard tissues, whereas all other bioprinters are relegated to printing liquid inks and subsequently form soft tissues only.”
Dr. Ringeisen and his colleagues were the first to use BioLP to print viable microorganisms directly from soil samples, opening the possibility for the discovery of new microorganisms and enzymes that could be used for everything from new antibiotic development to carbon sequestration and biofuels. The technology has already been used to 3D print “highways of surrogate cells” to regrow neurons in the spinal cord, and the potential lifesaving applications of BioLP are many. The NRL hopes to use it in the future for the treatment of common military ailments like traumatic brain injury (TBI), radiation exposure, burns and hearing loss.
Dr. Ringeisen is furthering bioprinting research with the recent establishment of a DoD Bioprinting Consortium, which is bringing the NRL together with the Uniformed Services University for the Health Sciences and the Walter Reed National Military Medical Center to study potential treatments for TBI and radiation exposure, as well as skin replacement therapies, using bioprinting technology.