3D printing technology has incredible potential and there seems to be very few limits to its application as scientists refine and improve the technique. While it can currently be used to make custom prosthetic devices, bioengineers want to take it a step further and create cellular materials. Possible uses include specialized cartilage, bone or skin or possibly simple, whole organs like bladders.
A new special issue of Trends in Biotechnology is dedicated to biofabrication – the use of biological materials to construct biological therapeutics, products or systems. Scientists take a moment to consider the state of the science as well as where it could lead in the future, and in the video above, you can take a look inside a biofabrication lab.
One application is so-called “organs-on-a-chip,” microscopic systems in 3D that imitate the structure and function of tissue. As medicine tailored to individuals gains traction, such systems could be of great benefit to patients. Researchers have been able to screen drugs and analyze physiology using the chips; so far lung, pancreatic and gut tissue has been grown on the chips using human stem cells. 3D printing could help researchers oversome some of the limitations of the technology such as coast and speed.
"The intersection of 3D printing for microfluidic fabrication and bioprinting 3D tissues shows great promise in the direction of single-step organ-on-a-chip engineering and can allow greater flexibility and throughput in the research process," said Savas Tasoglu, an Assistant Professor at the University of Connecticut, who works to create new applications of 3D printing in this area.
"In future studies, more advanced 3D bioprinters that can print a range of viscous materials may be utilized to print and fabricate both the microfluidic platform and patterned complex tissues inside the device simultaneously. Such closed integrated systems will greatly simplify the fabrication of organ-on-a-chip models and enable faster iterations of organ-on-a-chip designs," he concluded.
Expanding on that idea, scientists see promise in the use of organoids in drug evaluation. Those organoids - miniature, simplified, multi-cellular versions of organs - can be generated with 3D printing.
"Along with the development of novel advanced bioprinting techniques, fabrication of physiologically relevant tissue models will become a vital tool in pharmaceutical development in the next decade," said Ibrahim Ozbolat and Weijie Peng of Pennsylvania State University and Derya Unutmaz of The Jackson Laboratory of Genomics Medicine. "Integrating with other 3D biofabrication and supporting techniques, bioprinted organ/human-on-a-chip models and microarrays will significantly decrease the attrition rate of new therapeutics in preclinical trials and significantly shorten the drug development process."
Another use would be the manufacture of skin that could be a huge help to burn victims and other patients with major wounds. Skin printed onto a collagen gel was shown to have biologically normal markers and connections at 10 days following cultivation. A different group was able to grow blood vessels inside such cell layers.
"It is now a reality to utilize sophisticated machine control to create tissue-engineered constructs," explained Wei Long Ng of the Nanyang Technological University in Singapore. "Although the ultimate goal of bioprinting a skin equivalent with complete functional performance has yet to be achieved, bioprinting shows promises in several critical aspects of skin tissue engineering, including creating pigmented and/or aging skin models, vasculature networks, and hair follicles."
Investigators are working to improve the creation of 3D networks of blood vessels in bioengineered tissue, a requirement for successful implantation and subsequent imitation of natural human anatomy.
"Vascularization is currently regarded as one of the main hurdles that need to be taken to translate tissue engineering to clinical applications at a large scale," say bioengineers Jeroen Rouwkema and Ali Khademhosseini, both of MIT and Harvard. "It is clear that approaches that focus on the active patterning of vascular cells within engineered tissues provide the highest level of control over the initial organization of vascular structures."
More complex biological systems are still under development, but researchers hope to help people with devastating cranial and facial injuries. Hurdles remain, but craniofacial reconstruction could be possible one day using 3D printing.
"A promising future approach for the treatment of external craniofacial tissues could be a handheld bioprinting device that will enable the delivery of cells into tissues such as skin or cartilage," explained surgeon Dafydd Visscher of the VU University Medical Center in Amsterdam.
"For now, focusing on the optimization of bioprinting technologies to enhance the self-repair capabilities of tissues in the craniofacial area seems a logical first step in clinical bioprinting. With the need for long-term clinical studies, intelligent polymers, and ultimately good manufacturing production of bioprinted constructs, there is still a long road ahead.”
Further reading on biofabricated organs: Knowlton et al.: "Towards Single-Step Biofabrication of Organs on a Chip via 3D Printing" https://www.cell.com/trends/biotechnology/fulltext/S0167-7799(16)30087-7
More information on fabricating skin: Ng et al.: "Skin Bioprinting: Impending Reality or Fantasy?" https://www.cell.com/trends/biotechnology/fulltext/S0167-7799(16)30025-7
Additional details regarding craniofacial resconstruction: Visscher et al.: "Advances in Bioprinting Technologies for Craniofacial Reconstruction" https://www.cell.com/trends/biotechnology/fulltext/S0167-7799(16)30005-1