With all of the other advancements that 3D printing has brought, it’s no surprise that attempting to build a 3D human heart would be next. A team at the University of Louisville has printed two-ventricle cylinders and small veins with cells. According to Stuart Williams, a cell biologist leading the project, "They have also successfully tested the tiny blood vessels in mice and other small animals,” The Associated Press reported.

However, the researchers do point out that it will be years, maybe decades, before the 3D heart will ever be transplanted into an actual person. Williams, on the other hand, is hopeful that in three to five years they can assemble an entire heart — what would be called a “bioficial heart.” He says the biggest challenge he faces is getting the cells to work together as they would in a normal heart.

“Before any organ can be engineered — whether it's printed or built by hand — there is much groundwork that must be accomplished. Vital to the process is a thorough understanding of cell biology," said Dr. Anthony Atala in an opinion piece he wrote for CNN.

Different labs all over the world have already printed up different organs such as lungs, arms, the liver, and other organs. Last month, the world’s first skull transplant using a plastic printed piece was used on a 22-year-old-woman suffering from a bone structure condition. In October of last year, a dad created a 3D hand for his son, who was born without fingers on his left hand. The printer was priced at $2,000, but the materials for the hand only cost about $10.

This technology has already proven effective in many cases. "We're experiencing an exponential explosion with the technology," said Michael Golway, president of Louisville-based Advanced Solutions Inc., the builders of the printer that William used for the 3D heart.

3D shares have also shown a steady increase in the market. Last year, CNN Money reported that there was a steady increase in shares throughout 2013. Despite the costliness of the machines, and sometimes the materials, it looks like more research is going to be invested into developing this technology, especially for human organ transplants.