3-D printing for medical applications is no longer the future, it is now. 3-D printing or additive manufacturing is a process of making three-dimensional objects from a CAD model or a digital 3-D model. The creation of a 3-D printed object is achieved using additive processes. In an additive process, an object is created by laying down thin successive layers of material in the form of liquid or powdered plastic, metal, or cement and thin fusing layers together. 3-D printing is the opposite of subtractive manufacturing which is cutting out or hollowing out of a piece of metal or plastic with a milling machine. Liquid polymer form is the most common type of 3-D printing. The polymer is cured rapidly by ultraviolet light. This is the primary use in medical applications and is referred to as stereolithography.
Researchers have created the most advanced artificial cornea using 3-D printing and bio-ink made with human stem cells. The cornea is the protective, clear outer layer covering the eye. 3-D printed artificial corneas made of decellularized corneal stroma and stem cells. Stroma is a type of cell that makes up certain types of connective tissue (supporting tissue that surrounds other tissues and organs). Decellularized tissue is made by chemically or physically removing the cellular compartment of living tissue.
This process uses a simple, low-cost 3D bio-printer to form the shape of a human cornea. This bio-ink was successfully expelled out of the printer. The researchers then showed that stem cells on the printed cornea grew, creating a human cornea.
3D-printed corneas will now have to undergo further testing. It is likely patients will have to wait several years before 3-D printed corneas are approved for use by the FDA in the United States. These devices represent help to those with severe corneal damage or disease. This technology may eventually replace the use of donated corneas in eye surgery. Bypassing the complications of finding a donor match from deceased donors where the need far exceeds the supply.