According cases that result in the need for

According to the American Transplant, 116,000 people are currently on the waiting list for a lifesaving organ transplant. Liver failure, collapsed lung, kidney failure, etc. are just some medical cases  that result in the need for organ transplantation. Few are lucky enough to receive a transplant within weeks, however for others it could take years and unfortunately some never receive them. Researchers have tried countless times to limit the number of organ transplant casualties and only a few have shown success. That was until 2003 when Thomas Boland of Clemson University patented the use of inkjet printing for cells making 3D printed (also known as bioprinting) organs a possibility for transplantation. Since then bioprinting has been further developed to encompass the production of tissues and organ structures that are compatible with their host Years later advancements in bioprinting are accelerating leading it closer and closer to becoming a more common procedure. Here’s how Tandon, a 35-year-old biomedical and electrical engineer, sees it working: “A doctor uses a CT scanner to image the damaged section of bone and takes a small sample of fatty tissue. The scans and the sample are sent to EpiBone, which extracts stem cells — undifferentiated cells that can essentially be programmed to perform a wide array of functions.”(Shaer 1) The key to bioprinting are the stem cells gathered from  fatty tissue. These cells are the biomechanics that out each cell of our body. Common shown through Tandon’s research the acquired cells are applied to either a custom cut model or are used a biomaterial (explained later on on). However, unlike bioprinted organs, EpiBone places their constructs into a specially designed bioreactor, only about the size of a can of soda, with a chamber cast in the shape of a 3D printed bone model. This is “to ensure that the company’s proprietary growth ‘cocktail’ passing through the chamber seeds the bone tissue uniformly.”(Shaer 3) A cocktail is a solution of both the host’s stem cells and a polymer that is crosslinked allowing the cells to perform regrowth. What emerges, a few weeks later, is a replacement organ that not only fits the patient exactly but is made out of the patient’s own cells. Research groups such as EpiBone are conducting incredible studies revolutionizing modern regenerative medicine. For example, Epibone has begun a study that implants newly grown cheekbones into 16 pigs at the Louisiana State University School of Veterinary Medicine. Though research may seem close, Tandon ensures that, “it will be some time before EpiBone is ready to move on to human beings.”(Shaer 6) Currently, 3D organ structures have reacted more like human organs than the 2D tissue samples used beforehand. This information provides the medical industry with a huge potential booster for the implementation of bioprinted organs later on in the future. Thresholds are constantly being broken in bioprinting through conducting experiments and studies. Through research, biomedical engineers have discovered exceptional biomaterials for bioprinting and organ regeneration. Materials currently used in the field of regenerative medicine for repair and regeneration (including bioprinting) are based on naturally derived polymers including ,”(alginate, gelatin, collagen, chitosan, fibrin and hyaluronic acid, often isolated from animal or human tissues),”(Murphy 775) or synthetic molecules. The advantages of natural polymers for 3D bioprinting and other tissue engineering applications is their similarity to human ECM (Extracellular matrix), and their inherent bioactivity. The Extracellular matrix (ECM) is what holds the cells within the organ tissue together, our cells produce a group of extracellular molecules that provides structural and biochemical support to the surrounding cells. Because these cells are naturally made by the human body, natural polymers are the preferred biomaterials used in bioprinting.Although natural polymers are prefered there are certain advantages to synthetic polymers. One is specific is that they can be configured with specific physical properties to suit particular applications. However ,synthetic polymers, “possess the risk of the poor bio-acceptability but could also lead to the toxicity because of the toxic degradation.”(World Journal of Clinical Oncology 21-36) Even so, synthetic polymers hydrogels are attractive to bioprinting due to their,”hydrophilic, absorbent and manageable physical and chemical properties.”(World Journal of Clinical Oncology 21-36) Compared to natural polymers, synthetic polymers have mechanical properties allowing them to be configured to specific integration. Researcher Shen Ji and his team have found a way to make the best of both polymers by blending both natural and synthetic together. “Blends of synthetic and natural polymers have been used to develop mechanically tunable hydrogels with user-defined bioactivity,”(Ji 1) meaning that by incorporating both characteristics of natural and synthetic polymers allowing to make perfect matches for patients with configurations to specific integrations.In our everyday lives the field of biogrowth research may lack in popularity however, major studies have been conducted since before the development of bioprinters. Biogrowth was the prior stages leading up to the development of bioprinting. In its prototype stages, between 1999 and 2001, after a series of tests on dogs, Bioengineer Anthony Atala created custom-grown bladders that were transplanted into seven young patients suffering from spina bifida, a disorder that causes bladders to fail. By 2006, Atala announced that after close supervision the bioengineered bladders were working extraordinarily well. The marked history in bioprinting being that it was the first time a lab grown organ was successfully transplanted into a person. The possibilities are endless at this point. The skin-cell printer is one of several active projects developed by Atala that receives funding from the U.S. Department of Defense, The goal is to successfully create, “tissue regeneration initiatives for facial and genital injuries, both of which have been endemic among American soldiers injured in recent wars”( Sigaux 1). Anthony Atala has shown to be a remarkable export in the progression of bioengineering. In 2014 a group researchers led by Atala successfully implanted vaginas engineered using the patient’s’ own cells inteenagers suffering from are productive disorder called Mayer-Rokitansky-Küster-Hauser syndrome. Researchers have stated that, ” the main advantage of 3D printing technologies in large hard tissue and organ engineering is their capability to produce complex 3D objects rapidly from a computer model with varying internal and external structures.”( Wang 1) The functionality of 3D printers as well as the biological structure of the tissue in our organs gives an advantage to researchers.  All in all the field of bioengineer is ever growing in popularity as more procedures and uses are being developed every day.With the multitude of discoveries within the field of bioengineering comes many economic and scientific assumptions and predictions  being expressed for the future of bioprinting. The potential for the technology is never ending, and the industry is predicted to boom even more over the next ten years. According to a report report published by IDTechEx estimates that, ” the global 3D printing market will reach $7 billion by 2025, with about half coming from 3D bioprinting.”(Shaer 1) Research groups such as EpiBone have speculated that the future of their technology could be used to treat anything from bone loss and broken femurs as well as facial fractures and genetic defects. A guarantee made by researchers is that organs produced by “computer-assisted manufacturing” (Bioprinting) will be faster to implant with little no complications.  Once this limit is overcome, the production of “ready-to-implant”(Shaer 1) organs will become possible. These advancements in 3D bioprinting open up a new frontier for oncology research and could possibly be used for cancer treatment and removal. However, due to cancer’s effects on a microscopic scale more research is being focused on bioprinter technology and its compatibility with physiologically relevant materials and cells. A common goal is for biomaterials to have the ability to maintain complex combinations or gradients to achieve desired functionality. Once fully achieved, complex organs such as livers and hearts can be printed within a days time. Although still in its infancy bioprinting is a promising solution for addressing the growing international organ shortage. The ability to generate tissues for transplant on-demand with desired functionality and reduced immune response shows promise for the future of fabricating artificial organs. This potential for the future of bioprinting is appealing to investors because its promise of innovation. Funding from investors seems never ending as the economic future of bioprinting seems promising.Despite the constant discoveries and advances in bioprinting there are a few current limitations that are restraining the universal use of bioprinting. The practical limitation in terms of graft size is the ability to create a vascular network.(Sigaux 1) The process of bioprinting consists of printing with a single material, then each layer is connected and mechanically supported as it is placed. However, voids such as veins appear in a layer, leaving the possibility for subsequent layers that are deposited after it to collapse causing a cascade of offset features making the organ dysfunctional. One possible solution to this problem is to incorporate a sacrificial material, a method widely used in the fabrication of suspended structures such as arteries and veins. According to Nicolas Sigaux in his publication “Is 3D Bioprinting the Future of Reconstructive Surgery?”, “The lack of reliable methods to print pre-vascularized tissues is a hurdle that cannot be overlooked.”(Sigaux 1) This problem is common in bioprinting making it difficult to print large- scale tissues without complications. So far many of the small-scale tissues researchers currently print can survive bioprinting alone, “but full-scale organs and large tissue constructs will require an embedded vasculature as well as mechanically robust conduits to connect to host arteries and veins.”(Sigaux 1) Meaning in order to develop functional large organs, the vascular system within it the organ must be embedded separately as opposed to printing them along with the organ. Eventually these complication will be resolved and the future of bioprinting will thrive in the field of medicine and technology.Although bioprinting is relatively new in regenerative medicine, researchers have developed an alternative approach to bioprinting known as vivo bioprinting. With this approach cell and materials are deposited directly on or even inside the patient. “Currently, this approach has been used to bioprint skin directly into wound or burn defects and by others to bioprint bone into calvarial defects in mice,”(Murphy 784) states Sean Murphy in “3D bioprinting of tissues and organs” Murphy predicts that with the increasing speed and accuracy of 3D bioprinters, vivo bioprinting may become viable for the regeneration of tissues immediately after injury or during surgery. Another fascinating possibility for bioprinting is the integration of bioprinters into minimally invasive surgical robots. If possible this could potentially be able to remove and replace tissues during one surgery as well as having the ability to accelerate the healing of the tissues removed during surgeries. Murphy then states that, “3D-bioprinted tissue constructs are being developed not only for transplantation but also for use in drug discovery, analysis of chemical, biological and toxicological agents, and basic research.” (Murphy 784) The possibilities of bioprinting are endless and the potential uses are still being determined.Bioprinting is the procedure of the future, for now it requires further testing however, boundaries are being broken each day in the constant development and research brought together by the ideas of some the world’s best biomedical engineers. Although there are significant hurdles in the way such as the limitations of bioprinting and the ability to print vascular systems, innovation are being made each day. As the field of regenerative medicine continues to progresses toward printing tissues to specific integrations, beginning with 2D tissues such as skin, through to hollow tubes such as blood vessels, to hollow non tubular organs such as the bladder, and finally to solid organs such as the kidney, we will have to address increasingly difficult challenges, including cell and material requirements, tissue maturation and functionality, and appropriate vascularization and innervation however, researchers continue to have the common goal of eventually integrating bioprinting as an everyday procedure. In order to insure this goal research will be needed to overcome these challenges and to realize the potential of bioprinting eventually transforming the field of regenerative medicine.  One day someone in need of a transplant will no longer wait in fear for a compatible match to pop up, it is speculated that in the future bioprinted organs will take as little as a week to grow and be specially prepared for the patient. The National Donor list will gradually decrease, and the average lifespan of a person will increase. Many of the challenges facing the 3D bioprinting field relate to specific technical, material and cellular aspects of the bioprinting process.