By Grissel Trujillo de Santiago
Up to now, organ shortage is an ever-growing problem that affects millions of people around the world. Fortunately, the application of science, in particular 3D bioprinting technology, towards the attainment of health holds the bold and hopeful promise of opening the door to the production of functional organs for patients registered on never-ending waiting lists.
The manufacture of hollow bodily organs, such as the bladder, or tube-like structures, like the urethra, is now a reality. However, producing more complex solid organs, such as the kidneys or liver, presents a much greater challenge. That’s why our research team has worked diligently towards making the dream of organ bioprinting possible, developing biomaterials and techniques that defy the current limits of this technology.
3D bioprinting is an additive manufacture technology that involves the layer-by-layer deposition of a mixture composed of biomaterials and living cells intended to form a predesigned 3D structure. Both the architectural design and the choice of materials and cells are defined depending on the tissue to be produced. Once printed, the construct is provided with nutrients and incubated under sterile conditions. Over time, the cells contained in the structure undergo proliferation and maturation, thus forming artificial biological tissues.
Challenges and possible solutions
Many challenges are still ahead. The technologies currently available continue to be limited in their capacity to fabricate biological tissues of relevant size. Production of tissues thicker than 0.2 mm poses a great challenge, as the cells encapsulated within do not get enough oxygen for survival.
One solution to this problem is vascularization, that is to say, the incorporation of blood vessels capable of continuously supplying oxygen and nutrients to the tissues. Another challenge facing bioprinting technology to date is the need to produce biological structures with a microarchitecture similar to that naturally present in human tissues. These two aspects, the fine microstructure and the presence of blood vessels, are essential to fabricate functional artificial tissues and keep them alive and healthy.
Our research team is working on the development of technologies that recreate tissue microstructure and incorporate blood vessel-like structures practically and efficiently.
Making the difference
We have found in chaotic flows a simple yet powerful tool to achieve both objectives as they allow us to manipulate fluids to create mathematically predictable structures. In this context, chaos does not involve disorder but evolves exponentially. It is very efficient for architecture generation. The structures are formed through repeated processes of deformation and folding of the flow, and a very high resolution is attained (in micron scale). Fortunately, these chaotic structures emulate those that are naturally present in human tissues.
Our chaotic bioprinting system design project, which earned the L’Orèal-UNESCO-AMC-CONACyT 2019 Award, allows for the simultaneous use of multiple materials. In the interest of fabricating vascularized tissues, two types of materials will be used: permanent and fugitive. The former will make up solid tissue while the latter will be removed from the construct to create hollow structures similar to the blood vessels in human tissues. This artificial vasculature will allow for perfusion of fresh, oxygenated medium to provide nutrients and keep the tissue alive.
Two decades from now, we are very likely to witness the emergence of 3D bioprinting technologies capable of producing transplantable organs for patients. Our research work decidedly aims to contribute to the realization of that dream.
About the author
Grissel Trujillo de Santiago received her Ph.D. in engineering science from Tecnológico de Monterrey (2014). She joined the National System of Researchers (Level I) in 2015.
She was a postdoctoral researcher at Dr. Ali Khademhosseini’s laboratory (Harvard-MIT), where she furthered her work on biomaterials applied to tissue engineering. She received funding for her postdoctoral work from CONACyT, Fundación México en Harvard, Tecnológico de Monterrey, and MIT, which has led to the publication of thirteen research papers to date. She is currently a research professor at Tecnológico de Monterrey and a member of the Nanotechnology for Device Design Research Group. She is a lecturer for the undergraduate program in biomedical engineering and the postgraduate programs in nanotechnology and biotechnology.
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