Regenerative Medicine: 3-D Printed Organs for Human Transplant

Having enough organs for transplant is an ongoing issue that transplant centers face. Currently, the only way that a person can get a transplant is by getting picked off of the National Transplant Waiting List. Seventeen individuals die each day while awaiting an organ transplant. Statistics are hard to change because the only way for an organ to be harvested is through donation. Finding donors is difficult enough--finding a match to a recipient is even harder with that small selection of people. Another huge obstacle that is out of the healthcare facilities and transplant centers’ hands: organ rejection. So even if someone is lucky enough to get another chance of life, their body might reject the new and foreign tissue. New options for these individuals are necessary. So is there another way to shorten the time of being on the waiting list? In the near future, there might just be bioprinting. 3-D printing organs, also often called bioprinting, is the process of using stem cells to make them into cellular structures for transplantation.

Stem cells have the possibility to be any type of cell throughout the body, and the stem cells that would be used for bioprinting are the patient's stem cells. You might wonder, where do the stem cells actually come from? There are a lot of categories of stem cells, but for bioprinting, we just need to know about embryonic stem cells. You might be able to already recognize why they are used and where they come from. Since embryos grow into every type of cell in the body, they have the potential to develop into any cell tissue needed for transplant. So the possibilities are endless. The question still lies, where do they come from? They originate from a sperm cell being fused with an egg cell to create an embryo. At the beginning stages of development, the cells begin to divide. This creates numerous identical cells with no differentiation between them called, you guessed it, stem cells. These stem cells would continue on to develop into every tissue in the body, but when talking about the scientific application to the medicine they are used in different ways. There are a lot of ethical entanglements that are involved with the use of stem cells in this way because of the ongoing argument on what is considered a person or not. These harvested stem cells are collected and stored in cultures to be grown into the various tissues that are needed.

There is another way that stem cells can be created. When referring to ethics, this usually has more preference because it does not require a fertilized egg. In this scenario, there is no embryo. How it works is that a human egg has its nucleus removed. Then a nucleus, from the cell of a tissue you are trying to replicate, is inserted into the human egg with no nucleus. After this fusion, it begins to replicate in a way that an embryo would, and after a period of replication, you would have enough stem cells to be used as a culture to get the end product of an organ for transplantation. Those cellular structures that could be created include but are not limited to skin, cornea, heart, kidney, liver, and lung tissues. Stem cells can be guided into becoming specific cells that can be used to regenerate and repair diseased or damaged tissues in people. With that being said, these cultures can be used in numerous ways from organ transplantation to testing drug effectiveness to brain disease treatments. The possibilities are endless. It is important to keep in mind that if the organ has a lot of different structures and is more complex then it would take longer than others to be produced compared to something like a blood vessel for instance. Currently, simple structures like a blood vessel are already being produced, so something like a heart is not too far out of reach.

Now that there are these stem cells, the next step would be the actual bioprinting itself. A special 3-D printer is necessary that can be used with bio-ink solutions because this soft material is a lot different from what traditional 3-D printers are typically using, materials like plastic and metal. That bio-ink I mentioned is a hydrogel solution that contains the live cells and other jelly-like materials to ultimately become a tissue structure. They are printed onto materials that encourage the growth and development of the newly printed tissue.

There is one last significant game-changing aspect of bioprinting; the fact that the 3-D printer would be using an individual’s own cells, so the chance of rejection reduces greatly. This idea solves every issue that the entire organ transplant process poses. From the lengthy waiting time on the National Transplant Waiting List to the chances of organ rejection, bioprinting is the future of medical research and healthcare.

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