The idea of using a printer connected to a computer to print a working 3D object seems straight out of a science fiction movie but the technology is very much real today. Going by the present developmental trends in the 3-D printing technology, a future where printing a tangible and practically usable object with the click of a button seems to be a real possibility. The technology of 3D printing was invented by Charles Hull in 1984 using a technique called stereolithography that prints multiple thin layers to build up an object (Barnatt, 2016). The technology is an intuitive integration of Computer Assisted Design and state-of-the-art printing technology to create 3D objects based on digital inputs. NASA has already adopted the technology to print machine parts at the international space station and the Oak Ridge National laboratory has been successful in printing an entire body of a car (Patwardhan, 2015). The prospect of 3D printing technology in the healthcare sector is enormous and market analysts predict that by the year 2020, the 3D healthcare market will cross the $1.2 billion mark (Patwardhan, 2015).
In the field of medical research, the practice of generating cell cultures and using them to create tissues such as skin and blood vessels in the laboratory has already been mastered. However, creating an entire organ in the laboratory that is viable and can be implanted in a living body without any complication is still a major challenge. The 3D printing technology is opening up new avenues in this direction and medical researchers have already been able to print viable organ tissues. With regards to the printing of an entire organ, the research is still at its infancy but holds great promise for future given the rate at which it is developing (Griggs, 2014).
Bioprinting: Creating ground-breaking prospects in healthcare:
Fig 1: A concept 3D printed heart (Atwell, 2013)
While the 3D printing technology is highly sophisticated and complex, 3D bioprinting is a whole new ball game with even greater complexities. While printing biomaterials a wide range of factors need to be addressed such as the type of biological material used for printing, cellular characteristics, biological sensitivity issues to name a few. For this reason the process of printing requires involvement of different technological domains such as molecular biology, cell biology, tissue engineering and physics. At the moment, researchers are already using the technology to print and transplant skin tissues, cartilages and blood vessel grafts but the printing and transplantation of entire organs such as heart, lungs and kidney is still not a reality (Murphy and Atala, 2014). The idea of printing a working kidney or a heart in a laboratory seems to be overambitious today but researchers working in the field would say otherwise. Given the high quality of healthcare that people are receiving today in USA and Europe the life expectancy has increased significantly. This has in turn increased the need for organ transplants and it is reported that on average around 15 Americans die every day for not getting an organ transplant on time. Medical researchers are hoping that with the successful bioprinting of viable organs this shortage will cease to exist and will further improve people's quality of lives. According to the researchers, an additional benefit of bioprinted organs would be their use in processes such as drug toxicity testing and vaccine testing, considered far more accurate than the currently used animal testing models (Griggs, 2014).
The 3D bioprinting technology is not just about printing tissues and organs that can be implanted in a living body. The technology has made it possible for surgeons today to recreate 3D models of the organs before performing a complicated surgery. This means that there is no need to rely only on CT scans and there is much greater chance that the outcome of the surgery will be far more successful (Zaleski, 2015). 3D models can be extremely beneficial for neurosurgeons who perform some of the most complicated surgeries on extremely complex anatomical structures. A 3D model of such complex neuroanatomical features will allow them to plan their surgery to the tiniest possible detail and guarantee desired outcomes (Ventola, 2014)
Coming back to the implants, a very interesting surgery was performed in the Netherlands in 2014 where doctors were able to replace major parts of a patient's skull bone with 3D printed replacements made out of plastic. Similarly, in 2015 a team of doctors in Spain replaced major parts of a patient's sternum and rib cage with 3D printed replacements made from titanium. Another interesting development in the field of prescription medicine is the use of 3D bioprinted drugs. In 2015, FDA approved the use of the first 3D printed drug called Spritam prescribed for epilepsy. Developed and created by Aprecia Pharmaceuticals, the drug is printed using biochemical ink and there are possibilities that its efficacy is increased through the customization of the dose according to the genetic makeup of the patient. However, the real benefit and challenge lie in successfully mastering the bioprinting technology at the molecular and cellular levels (Zaleski, 2015). Researchers at the Cardiovascular Innovation Institute (CII) in Louisville have made great progress in the 3D bioprinting technology and are currently working towards developing an entire working heart that will be transplantable in patients. They are also making great progress in stem cell printing that will effectively nullify all the ethical issues surrounding the current protocols of retrieving the same from embryos. It is anticipated that successful stem cell printing along with 3D bioprinting will revolutionize the field of regenerative medicine and will offer the means to quickly repair and replace organs and improve surgical outcomes (Gilpin and Hiner, 2016). Another revolutionary concept that researchers are currently working towards and making appreciable progress is in situ 3D bioprinting. With the potential of completely revolutionizing the field of medicine, the technique will print cells directly on the body and will dramatically reduce the healing period. Researchers at the Wake Forrest School of Medicine have already developed a "skin printer" and have already done the initial tests with laboratory mice. Skin injuries on the laboratory mice were 3D scanned and the digital data was used to direct the skin bioprinter head to spray a mixture of skin cells, coagulant and collagen on to the wound. The injuries healed within 2-3 weeks compared to normal healing process of 5-6 weeks (Barnatt, 2016).
Hurdles and ethical concerns surrounding 3D bioprinting:
Given the regulations of Food and Drug Administration, full scale 3D bioprinting of tissues and organs face certain restrictions but going by the current rate of progress in the sector, they will certainly not remain for long. At the moments the regulations that exist are also not very clear as the technology is relatively new. For this reason, research centres and private companies are carrying out their own studies without any common set of guidelines specifically made for 3D bioprinting. Concerns are also being raised regarding the affordability of the technology. Many people are of the opinion that 3D printed organs, when they come to the market, will only be affordable to the super rich and will fail to make a real positive impact on the general health care outlook. It is also anticipated that successful organ printing will create serious ethical issue and will easily bypass the intellectual property rights of thousands of companies making them unsustainable in the market (Mearian, 2014). Another major hurdle in 3D bioprinting technology is the durability of the supporting connective tissue and the development of a fully functional vascular system to nourish the organs. Safety is another major concern surrounding 3D bioprinting due to its ramification for human health (Dodds, 2015). There is also a possibility that those who will have the financial means to afford the technology will try to explore ways to receive enhancements that will give them a competitive edge over their contemporaries and this will create unavoidable ethical and moral dilemmas.
There is doubt in the fact that 3D bioprinting can greatly improve the quality of healthcare and will go a long way in saving people's lives. The technology is already being used extensively in the field of prosthetics with great success but with regards to printing viable organs much more research is needed. Fears and ethical concerns are already being expressed regarding the possible misuse of technology and it will necessary on the part of the researchers to negate those apprehensions and move towards a direction committed to the welfare of the mankind.
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