THE FUTURE OF MEDICINE: 3D PRINTED ORGANS BY JULIA PENG ANALYZING THE ENGINEERING OF HUMAN ORGANS THROUGH 3D PRINTING TECHNOLOGY T hree years--that’s how long New Yorker Tim McCabe has been waiting for a kidney transplant. Diagnosed with ulcerative colitis as a teenager, Mc- Cabe has been suffering from deteriorating kidneys ever since. Each day, McCabe waits by the phone, anticipating news of an available kidney, but each day, he is met with disappointment. Having left his job as a highway inspector due to his declining physical condition, McCabe now spends his days confined by nonstop dialysis treatments, hoping to survive long enough to watch his two sons grow up. 1 This is the unfortunate reality for many Americans awaiting organ transplants, as there is a seemingly perpetual organ shortage crisis in the U.S. In the last ten years, the number of patients required a transplants has more than doubled, yet the actual number of transplants performed has remained stagnant. There are currently over 119,000 people awaiting an organ transplant, but in 2015, only 30,970 trans- plants were performed, with the wait time for each transplant averaging 3 to 5 years. Every 10 minutes, another person is added to the waiting list, and every day, 22 people die waiting for a transplant. 6 So what can we do to solve this issue? What if there were a way to make a new organ on demand, eliminating the need for donor compatibility and absolving the waiting list crisis? The solution may lie in 3D bioprinting, the manufacturing of new tissues and organs using 3D printing tech- nology. This would involve taking a sample of a patient’s cells and using those cells to ‘print’ a new organ by depositing cells and biomaterial layer by layer, creating a tissue structure identical to that of natural human tissue. Over the years, researchers have developed and improved upon meth- ods of printing vital human tissue, and this engineering technology has now advanced to a point where systematic organ printing may be on the horizon. Berkeley Scientific Journal | FALL 2016 The general 3D tissue printing process that researchers have been using does not deviate much from traditional 3D printing; the major difference is that the printer deposits cellular biomaterial instead of synthetic material. The printing process involves three major steps: preprocess- ing, or the development of the computer blueprint; processing, the depositing of biomaterial; and post-processing, or tissue maturation and conditioning. In the processing stage, there are currently three main approaches to depositing biomateri- al: inkjet, microextrusion, and laser assist- ed printing. Thermal inkjet printers heat the printhead electrically, forcing droplets of material out of the nozzle. Microextru- sion printers use pneumatic (operated by air pressure), piston, or screw dispensing systems to extrude beads of material from the nozzle. Laser assisted printers use laser-induced pressure to propel cell ma- terials onto a collector. Each printer type has its own set of advantages and disad-