Pig hearts, kidneys and lungs may also become viable candidates for transplants if the technique is perfected.

CNN: Researchers clone pigs

First these results have to be replicated in the larger pig hearts Those experiments are under way at the University of Minnesota.

CNN: New hope may lie in lab-created heart

It has two large freezers with human cells and human hearts, and a dozen stainless steel sinks containing pig hearts immersed in a colorless liquid.

WSJ: Science Fiction Comes Alive as Researchers Grow Organs in Lab

While the beneficial results in pig hearts were particularly important due to their resemblance to human ones, two challenges remain before the same technique can be safely attempted in people.

WSJ: Nanotechnology Holds Promise for Heart Patients

Taylor says they've already started experimenting with pig hearts, which are closer in size to human hearts and because pig hearts are already used for replacement parts for some human heart patients.

CNN: New hope may lie in lab-created heart

The scientists mixed it with the VEGF and injected the combination into the hearts of two groups of test animals, rats and pigs, in which they had induced heart attacks. (Pig hearts bear significant similarities to human ones.) In both cases, instead of being washed away, the VEGF stayed on the lattice and slowly got released over several weeks.

WSJ: Nanotechnology Holds Promise for Heart Patients