Researchers say a discovery could increase the availability of organs and tissues for transplants.

Right now, experts say more than 60 percent of the hearts and lungs donated every year have to be discarded because they cannot survive outside of the body any longer than four hours.

So this discovery could mean donated tissue and organs could have a longer shelf life.

Currently, only about 40 percent of donated hearts and lungs make it into a recipient patient. With this technique, doctors believe it would ensure that no organs are wasted, possibly eliminating the need for transplant waiting lists.

In a lab at the University of Minnesota's mechanical engineering building, Professor John Bischof and his team show us their newly discovered preservation technique on a piece of a pig's heart valve.

It's a discovery that Dr. Erik Finger, a transplant surgeon says could make more organs available, because they could be preserved longer, which would help more patients.

"The longer you keep the organ on ice the worse things are generally, the worse outcome you have. So if you could somehow preserve an organ and keep it on the shelf and use it when you wanted to, you have a lot of potential benefits," said Finger.

Here's how the preservation technique works: Researchers put a mixture which includes iron oxide nanoparticles into a vial with the human tissue. Then they put the vial in a machine for vitrification, a process that essentially cools the tissue. When it's time to warm that tissue they use an electromagnetic machine.

Bischof says it's the first time someone has figured out how to preserve and then rewarm large pieces of tissue without causing damage.

"So our innovation was to add the nanoparticles and scale it up so now we have this hope to go to a larger system," said Bischof.

Researchers say they will test this on rodent organs before they use it on human organs and Finger is hopeful that this technique will save more lives in the future.

"Depending on the organ, they may die if they don't get a transplant in time, so if we can improve the utilization and increase the number of transplants that are done, fewer people would die," said Finger.