How 3D Printing Will Change Medicine

The struggle to recreate human tissues in the laboratory is nearly as old as the medical profession itself. The cell as you all know, is the structural, functional and biological unit of all organisms, whether it is a single celled-bacteria or a 90 trillion-celled human! While these microscopic units appear simple, they are actually quite complex and almost impossible to build from scratch, which is why for the longest time 'growing' new human body parts in the laboratory seemed like an impossible task. That perception seems to be changing somewhat, thanks to the recent advent of 3-D printing.

One of the biggest hurdles to recreating human organs has been the challenge of combining the various cells that make up each one and ensuring that they are in the right place so that they can function as efficiently as the one that is being replaced. Now using these new machines, researchers can finally do that by 'printing' the different cells, one at a time and positioning them correctly within a structure. It is therefore no wonder that grafting researchers all over the world are busy developing almost every human organ possible, ranging from the ear to the kidney and liver and even the largest one of all - the skin! Here is a brief synopsis on their progress.

Ears

While the outer ears may appear superfluous, they actually plays a big role in hearing. Unfortunately, they sometimes fail to develop properly or become damaged, which is why the researchers at Massachusetts Institute of Technology and Cornell University have been trying to recreate them, since 2007.

They begin by converting the 3-D image of the human subject's ear into a digitized 'solid' ear using the printer to create the exact mold. They then inject the mold with collagen - the tough but malleable tissue that forms the outer ear and nose, that they extracted from rat tails. To this they injected 250 million cells from the cow ears. The collagen provided a dependable scaffold upon which the cartilage was able to grow and thrive.

What amazes lead researcher Lawrence Bonassar, an associate professor of biomedical engineering at Cornell University, is how fast the process works. According to him, it takes less than half a day to create the mold, one day to print it, a half hour to inject the gel and then a few days in nourishing culture media, before it's ready to be implanted.

Having perfected the technique, the researchers now hope to begin conducting tests using human cells, ideally from the person for whom the implant is being made, so that the probability of rejection can be reduced drastically. If all goes according to plan, they plan to have them readily available for the thousands of young children that suffer from microtia, a condition where the external ear is not fully developed, within three years!

Kidneys

To say that kidneys are amongst the most important organs of the human body is an understatement. They do after all help filter the blood stream and ensure that all harmful substances are duly removed and excreted. While recreating such a complex organ is no easy task, researchers at Huazhong University of Science and Technology in China's Eastern Zhejiang Province have already succeeded in the first step - 'Printing' out functioning mini kidneys capable of filtering blood and creating urine for excretion and, keeping them alive in the lab for a full four months! A full-size human kidney is hopefully, not too far behind!

Liver

Weighing between 1.44 to 1.66kg, the soft pinkish brown triangular liver that comprises of four disparate lobes is the largest internal organ and gland and one of the most important ones in the human body. It's many varied roles that include detoxification, protein synthesis and the production of biochemicals necessary for digestion, make it crucial for survival. These same qualities also make it hard to replicate synthetically.

But this hasn't stopped the researchers at San Diego based Organavo who are working on creating this complex organ with their 3-D printers. While still very much a work in progress, the building blocks that have already been built by them and other similar companies are expected to be very useful in testing the toxicity of new medicines on the human body.

Skin

Did you know that the skin is the largest organ in the human body? Not only does it encase all the organs, but it also, protects the body from external harm. However sometimes with larger injuries and burns, the skin itself needs some rescuing and re-grafting. The problem with current grafting methods is that in order to work, it requires a piece of skin from another part of the patient's body.

Researchers at North Carolina's Wake Forest School of Medicine are working on a project that completely eliminates this need. They have created a system in which a camera scans a wound to create a 3D image, and then new ‘skin’ is printed right onto the scrape or burn. In trials with mice, researchers were able to help heal skin injuries in record time. They hope that this will work as efficiently in humans not only improving healing times tremendously, but also reducing the risk of infection, which is a big issue today.

When Chuck Hill came up with the 3-D printing process that he coined 'sterolithography', in 1986, he would have never guessed that it may one day provide the answer to many of our problems - ranging from helping with school projects to feeding the growing world population to even, saving lives!

Resources: Gizmodo.com, Popsci.com,news.cornell.edu