Mark Davis was enjoying a successful career as a chemical engineer - until his wife was diagnosed with breast cancer. After chemotherapy treatments compromised her immune system and made her gravely ill, she insisted to her husband, "There's got to be a better way - you can fix this." Davis didn't think he could. "Cancer - what did I know about it?" he wondered. "It was way out of my comfort zone from a scientific point of view." Ultimately, he rose to that very personal challenge, and 10 years later, the first drops of IT-101, a revolutionary nanoparticle drug he invented, were injected into the first human, Ray Natha. A terminal cancer patient, Natha was expected to live only a few months, but IT-101 reversed that grim prognosis and, today, more than a year later, his cancer remains stable. In addition to his dramatic improvement, Natha experienced virtually no side effects during the drug trial.

While Davis focuses his efforts on human survival, other researchers are trying to save planet Earth. Spurred by the looming energy crisis, Nathan Lewis and Sossina Haile are working to invent a new kind of fuel that uses the sun to power the planet. They are attempting to produce a prototype for a truly alternative fuel source - an artificial leaf that emulates natural photosynthesis, converting solar energy into a usable, clean chemical fuel. They hope their pioneering solar cell and fuel cell technologies will eventually end our dependence on petroleum and provide an energy source that won't pollute our planet.

Tuesdays, 10/16-23/07 from 9-10 p.m. ET