Tissue Engineering
Definition:
Tissue engineering is the study of the growth of new connective tissue or organs from cells and a collagenous scaffold to produce a fully functioning organ. The goal is for the organ that is created to be put back into the donor host. This will eliminate the need for organs to be transplanted from a different donor and therefore there will not be any chance of organ rejection. The process of tissue regeneration begins with taking cells, through a biopsy, from the future recipient of the tissue engineered organ. Cells from the biopsy are cultured to make a cell bank. Then these cells undergo more changes in order to be ready for implantation. During this process, growth factors or cytokines can be added in order to promote cellular biochemical and physical activity. The cells that were taken will eventually secrete a new collagen rich neo-tissue which can then be inserted back into the original patient with no chance of rejection.1
Types:
There are many different methods that have been used in order to prepare structures to be used as tissue engineering scaffolds. Some of these methods are nanofiber self-assembly, textile technologies, solvent casting and particulate leaching, gas foaming, emulsification/freeze drying, thermally induced phase separation, electrospinning, hydrogel-biodegradable hydrophobic polymer hybrids and CAD/CAM technologies. The scaffolds usually do at least one of the following: allow cell attachment and migration, deliver and retain cells and biochemical factors, enable diffusion of vital cell nutrients and expressed products, or exert certain mechanical and biological influences to modify the behavior of the cell phase.
History:
Tissue regeneration has evolved from referring to prosthetic devices and surgical manipulation of tissues to what we know of it today. The key discovery in the field of tissue engineering came in the mid 1980’s when Dr. Joseph Vacanti and Dr. Robert Langer had the idea to design appropriate scaffoldings for cell delivery as opposed to seeding cells onto available naturally occurring scaffolds that did not have any physical or chemical properties that could be manipulated, which led to unpredictable outcomes. Tissue engineering was made mainstream with the public when a BBC broadcast on the potential of tissue engineering showed the mouse with the human ear from the laboratory of Dr. Charles Vacanti.
Today’s Situation/Diseases it can treat:
Tissue engineering has immense potential for the field of science. There are many different areas of research in tissue engineering related to regenerative medicine. One of the areas is controlling stem cells through their environment. Scientists are attempting to figure out how to control what type of cells that stem cells turn into. They have realized that there is a biomechanical element to controlling how stem cells transform into other cells, which may be very important for the future as scientists are trying to use stem cells for medical uses. Another way scientists are researching tissue engineering is by implanting human livers into mice. Researchers have engineered human liver tissue that can then be implanted into a mouse. The mouse still has its liver, but the added human component can process drugs like a human liver can. Scientists are also looking to engineer mature bone stem cells. They have taken pluripotent stem cells and made them into mature bone grafts for patients that could be transplanted into a patient. Studies have been completed on using lattices to help engineered tissue survive. The difficulty with engineered tissues is that they do not have any vascularity to take them nutrients. Without a blood supply, cells die very quickly. Therefore, scientists are looking at how lattices can act as vascular bodies to the tissues. Tissue engineering is helping to repair cartilage in humans. Cartilage is difficult to repair, however a researcher has produced a biological gel that can be injected into the cartilage to help it heal. Finally, the organ that is in greatest need of transplantation, the kidney, has seen great strides thanks to tissue engineering. A researcher took the kidney scaffolds with epithelial and endothelial cells and produced an organ that was able to produce urine, clear metabolites and reabsorb nutrients in rats. This has major potential for helping to reduce donor organ shortages and complications associated with anti-rejection medications.2
While there have been many great developments in the field of tissue engineering, there is still a gap in the areas of complex functionality, functional and biomechanical stability and vascularization of the scaffolding for organ function.3
Tissue engineering is the study of the growth of new connective tissue or organs from cells and a collagenous scaffold to produce a fully functioning organ. The goal is for the organ that is created to be put back into the donor host. This will eliminate the need for organs to be transplanted from a different donor and therefore there will not be any chance of organ rejection. The process of tissue regeneration begins with taking cells, through a biopsy, from the future recipient of the tissue engineered organ. Cells from the biopsy are cultured to make a cell bank. Then these cells undergo more changes in order to be ready for implantation. During this process, growth factors or cytokines can be added in order to promote cellular biochemical and physical activity. The cells that were taken will eventually secrete a new collagen rich neo-tissue which can then be inserted back into the original patient with no chance of rejection.1
Types:
There are many different methods that have been used in order to prepare structures to be used as tissue engineering scaffolds. Some of these methods are nanofiber self-assembly, textile technologies, solvent casting and particulate leaching, gas foaming, emulsification/freeze drying, thermally induced phase separation, electrospinning, hydrogel-biodegradable hydrophobic polymer hybrids and CAD/CAM technologies. The scaffolds usually do at least one of the following: allow cell attachment and migration, deliver and retain cells and biochemical factors, enable diffusion of vital cell nutrients and expressed products, or exert certain mechanical and biological influences to modify the behavior of the cell phase.
History:
Tissue regeneration has evolved from referring to prosthetic devices and surgical manipulation of tissues to what we know of it today. The key discovery in the field of tissue engineering came in the mid 1980’s when Dr. Joseph Vacanti and Dr. Robert Langer had the idea to design appropriate scaffoldings for cell delivery as opposed to seeding cells onto available naturally occurring scaffolds that did not have any physical or chemical properties that could be manipulated, which led to unpredictable outcomes. Tissue engineering was made mainstream with the public when a BBC broadcast on the potential of tissue engineering showed the mouse with the human ear from the laboratory of Dr. Charles Vacanti.
Today’s Situation/Diseases it can treat:
Tissue engineering has immense potential for the field of science. There are many different areas of research in tissue engineering related to regenerative medicine. One of the areas is controlling stem cells through their environment. Scientists are attempting to figure out how to control what type of cells that stem cells turn into. They have realized that there is a biomechanical element to controlling how stem cells transform into other cells, which may be very important for the future as scientists are trying to use stem cells for medical uses. Another way scientists are researching tissue engineering is by implanting human livers into mice. Researchers have engineered human liver tissue that can then be implanted into a mouse. The mouse still has its liver, but the added human component can process drugs like a human liver can. Scientists are also looking to engineer mature bone stem cells. They have taken pluripotent stem cells and made them into mature bone grafts for patients that could be transplanted into a patient. Studies have been completed on using lattices to help engineered tissue survive. The difficulty with engineered tissues is that they do not have any vascularity to take them nutrients. Without a blood supply, cells die very quickly. Therefore, scientists are looking at how lattices can act as vascular bodies to the tissues. Tissue engineering is helping to repair cartilage in humans. Cartilage is difficult to repair, however a researcher has produced a biological gel that can be injected into the cartilage to help it heal. Finally, the organ that is in greatest need of transplantation, the kidney, has seen great strides thanks to tissue engineering. A researcher took the kidney scaffolds with epithelial and endothelial cells and produced an organ that was able to produce urine, clear metabolites and reabsorb nutrients in rats. This has major potential for helping to reduce donor organ shortages and complications associated with anti-rejection medications.2
While there have been many great developments in the field of tissue engineering, there is still a gap in the areas of complex functionality, functional and biomechanical stability and vascularization of the scaffolding for organ function.3
- Rensselaer Polytechnic Institute. What is tissue engineering? Accessed on July 12, 2016 http://www.rpi.edu/dept/chem-eng/Biotech-Environ/Projects00/tissue/What%20is%20Tissue%20Engineering.htm
- National Institute of Biomedical Imaging and Bioengineering. Tissue Engineering and Regenerative Medicine. Accessed on July 12, 2016 https://www.nibib.nih.gov/science-education/science-topics/tissue-engineering-and-regenerative-medicine
- Vacanti, C.A. (2006). The history of tissue engineering. Journal of Cellular and Molecular Medicine, 10(3), 569-576.