The term tissue engineering is often synonymous with regenerative medicine. It is essentially the use of a combination of engineered material constructs, suitable biochemical factors and/or cells to improve or replace the function of a failing organ. Other applications of tissue engineering are the testing of drug efficacy and toxicity, as well as the basic studies of tissue development (Berthiaume, Maguire, & Yarmush, 2011).
Most tissue engineering methods utilize living cells; therefore the supply of reliable cells is essential. Cells are derived from two sources: 1) donor tissue and 2) stem cells. Stem cells have a high proliferative capacity and are pluripotent, making them suitable for deriving large cell quantities.
Another important issue to consider in tissue engineering is the cellular environment. The ideal environment allows cells to function as they normally do in native tissue. This can be mimicked through control of materials, mechanical settings, and the chemical background, hence the use of cell scaffolds (Berthiaume et al., 2011).
Scaffolding usually provides one of the following (Berthiaume et al., 2011):
a. Cell attachment and possibly migration
b. Retention and presentation of biochemical factors
c. Porous environment for diffusion of nutrients, metabolic by products and waste
d. Mechanical rigidity or flexibility
Some methods used in regenerative medicine do not involve utilising living cells prior to implantation of the scaffold/material. These methods rely on the host cells to migrate into the scaffolds. Cells exhibit the ability for directional migration, and this is dependent on the concentration gradient of bioactive signalling molecules present. Different types of cells encounter different obstacles dur...
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...o biological polymers are synthetic ones. Polymers such as polyfumarates and polylactic acid can be processed to form a range of 3D scaffolds with variable network structures/porosities and surface characteristics. Hydrogels are also a form of polymer and will be further described in a later section. They are popular due to its minimally invasive implantation and ability to gel in situ, providing a 3D cellular microenvironment with high water content (Stevens, 2008).
Bone has a composite nature, made up of both organic and inorganic components. As such, composite materials like HA-collagen nanocomposite systems aim to combine the toughness of polymers and the strength of inorganic materials. Despite the promising results, current composites are still mechanically inferior to that of real bone, as recreating the nanoscale order in organization of bone is difficult.
The cells unique nature has scientists intrigued to do research with the focus of finding a way that these cells can be used to replace patients’ injured or diseased tissues. Advancement is made to all the three types of stem cells namely embryonic stem cells, adult stem cells in addition to induced pluripotent cells. Embryonic cells are the building blocks of an embryo that is developing, and can develop into almost all body cell types. Somatic cells are found in the body tissues. They renew and regenerate in healthy bodies. The third type which is induced pluripotent is genetically modified embryo cells from skin cells.2 Research on these cells are geared towards saving humanity; a noble course.
“Through the isolation and manipulation of cells, scientists are finding ways to identify young, regenerating ones that can be used to replace damaged of dead cells in diseased organs. This therapy is similar to the process of organ transplant, only the treatment consists of the transplantation of cells rather than organs. The cells that have shown by far the most promise of supplying diseased organs with healthy cells are called stem cells.” (Chapter Preface)
Because stem cells are essentially a blank slate, scientists are theoretically capable of growing any human tissue cell. There is enormous medical potential in this. Stem cell research is the next step in advancing the medical field. It is comparable to the discovery of penicillin or the inoculation for smallpox.
Stem cell research began in 1956 when Dr. E Donnall Thomas performed the first bone marrow transplant (“Adult stem cells are not more promising,” 2007). Since that time, research has evolved into obtaining cells from a variety of tissues. According to stem cell research professors, Ariff Bongso and Eng Hin Lee (2005), “Stem cells are unspecialized cells in the human body that are capable of becoming cells, each with new specialized functions” (p. 2). Stem cells are in various adult tissues, such as bone marrow, the liver, the epidermis layer of skin, the central nervous system, and eyes. They are also in other sources, such as fetuses, umbilical cords, placentas, embryos, and induced pluripotent stem cells (iPSCs), which are cells from adult tissues that have been reprogrammed to pluripotency. Most stem cells offer multipotent cells, which are sparse...
The human body endures a great deal of wear and injury during its lifetime. It is for this reason that the body has several tissues that are capable of regeneration. Bone is one of those tissues that receives extensive use so it is necessary that it is strong in order to carry out its functions; however, it will occasionally face injury. Although our bones are capable of regeneration, a new method would help the elderly and others that have a more difficult time healing after injury. I viewed a “TED Talk” lecture, which discussed a new way of regenerating bone with the help of our own bodies. Molly Stevens, the head of a biomaterials lab, presented “A New Way to Grow Bone” where she discussed a new technique called “in vivo bioreactor”. She also answered why this new procedure is beneficial. Researchers like Stevens are constantly trying to find innovative new techniques and they do this by asking questions. The question that Stevens presented in the video was an intriguing one: “Can we recreate the regeneration of bone on demand and transplant it?”.
Since organs are on short supply throughout the world scientists have taken to trying to create organs in the lab. The field of organ growing is possible thanks to recent advances in stem-cell research and is commonly known as ‘tissue engineering’. Tissue engineering uses the patient’s own cells to build new organs or replace damaged tissues in the patient’s own organs, which is called grafting.3The process works by differentiating pluri-potent stem-cells into the cells that the patient needs. The cells are then allowed to grow and multiply in a nutrient solution. When the cells are in adequate numbers they are sometimes inserted into the patients existing tissue but are most commonly used to grow a new organ or tissue graft.
Research on stem cells is advancing knowledge about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. This promising area of science is also leading scientists to investigate the possibility of cell-based therapies to treat disease, which is often referred to as regenerative or reparative medicine. There is genuine scientific excitement over the concept of using the body's own cellular building blocks to regenerate damaged or ageing organs. Stem cells are one of the most fascinating areas of biology today. But like ...
Tissue engineering can join the list of medical advances that science-fiction movies beat reality to. This component of regenerative medicine is one of the newest and most intriguing aspects of medicine and is guaranteed to enhance the quality of health care universally.
Since human recognize the material, biomaterials have had initial development. As early as 3500 BC, the ancient Egyptians used sutures made of cotton fiber or horse hair, and in 16th century gold plate was used to repair jaw bone and ceramic materials were used to make dedendum, and so on. With the development of medicine and materials science, especially the success of the research and development of new materials, such as the rapid development of polymer materials in the 1940s provides a great opportunity for the research and application of biomaterials. It could be said that in addition to the brain and most
A real-life example of its application in the human body is in wound repair. The main focus of tissue engineering in this application is in artificial skin to treat burns but it can also be used in various other dermal diseases. An example of this is the Advanced Tissue Sciences Dermagraft, which is a 3 dimensional human neonatal dermal fibroblast culture that has been grown on a biodegradable scaffold and has been cryopreserved (Nature Publishing Group., 2014). The main function of a scaffold is to direct cell behaviour such as migration, proliferation, differentiation and maintenance of phenotype (Amoabediny, Salehi-Nik, & Heli, 2011). The use of this Dermagraft is in the treatment of foot ulcers that have developed as a side effect of long – term diabetes. According to clinical trials, significant healing occurred with this material especially when the Dermagraft cells were alive and fully functional.
damaged tissues. The emerging use of stem cell research is a relatively new concept. Due to the
Polymers: A great variety of polymers are used as biomaterials in medicine. Their applications vary from facial prostheses to tracheal tubes, from dentures to hip and knee joints and from kidney and liver parts to heart components. Polymeric materials are also used for medical adhesives and sealants and are also used for coatings that perform a range of functions.
First off, biomaterials have had a drastic increase in how much research is being done and how far they have come with actually coming out with materials that will benefit the population. The actual definition for a biomaterial is, “Any nondrug material that can be used to treat, enhance or replace any tissue, organ, or function in an organism” (Ige, Umoru, & Aribo, 2012). It is a very complicated field of study as one can tell from the definition. They can date back to the beginning of mankind. Some of the first recorded forms of biomaterials date back to Ancient Egypt, where they would use inserts in their mouth as fake teeth. We still do this today, except we are far more advanced now. We have the ability to create a fake tooth with properties that would make it almost real. “Humankind’s use of materials to augment or repair the body dates to antiquity, when natural materials such as wood were used in an attempt to structurally replace tiss...
"Artificial" tissue is grown-up from the patient's personal cells. However, when the harm is so dangerous that it is unbearable to use the patient's own cells, artificial tissue cells are grown. The trouble is in discovery a scaffold that the cells can grow and organize on. The features of the support must be that it is biocompatible; cells can adhere to the support, mechanically durable and recyclable. One successful support is a copolymer of lactic acid and glycolic acid.
The field of regenerative medicine encompasses numerous strategies, including the use of materials and de novo generated cells, as well as various combinations thereof, to take the place of missing tissue, effectively replacing it both structurally and functionally, or to contribute to tissue healing[29]