several thousand people belong to the biohacker scene in the u.s. like cannon, many of them see themselves as pioneers. >> i bet you when the very first astronauts went up into space, they might have known the engineers, they might have known the scientists, they might have been completely comfortable with all the science and the measurements, but every time they heard a rattle you know they went, "oh no, that's it, i'm in trouble." it's the same with me. every time i feel a tingle, "the battery is going to explode!" >> san diego on the west coast. here, too, researchers are exploring new territory. dr. darryl d'lima is trying to produce cartilage from stem cells. he wants use it to repair warn out joints with the help of a 3- d printer. >> what we do with the discarded tissue is instead of throwing it away, we bring it to the lab and we try to print fresh tissue, live tissue with a 3-d-printer. if that works, some day we think we might be able to print directly into the patient's knee. >> d'lima thinks that in 3 to 5 years that could be done right