Physics of the Future: How Science Will Shape Human Destiny and Our Daily Lives by the Year 2100

tricorders—like these in
Star Trek
—that can diagnose almost any disease; portable MRI detectors and DNA chips will make this possible.
    Tissue engineering grows new organs by first extracting a few cells from your body. These cells are then injected into a plastic mold that looks like a sponge shaped in the form of the organ in question. The plastic mold is made of biodegradable polyglycolic acid. The cells are treated with certain growth factors to stimulate cell growth, causing them to grow into the mold. Eventually, the mold disintegrates, leaving behind a perfect organ.
    I had the opportunity to visit Anthony Atala’s laboratory at Wake Forest University in North Carolina and witness this miraculous technology firsthand. As I walked through his laboratory, I saw bottles that contained living human organs. I could see blood vessels and bladders; I saw heart valves that were constantly opening and closing because liquids were being pumped through them. Seeing all these living human organs in bottles, I almost felt as if I were walking through Dr. Frankenstein’s laboratory, but there were several crucial differences. Back in the nineteenth century, doctors were ignorant of the body’s rejection mechanism, which makes it impossible to graft new organs. Plus, doctors did not know how to stop the infections that would inevitably contaminate any organ after surgery. So Atala, instead of creating a monster, is opening an entirely new lifesaving medical technology that may one day change the face of medicine.
    One future target for his laboratory is to grow a human liver, perhaps within five years. The liver is not that complicated and consists of only a few types of tissue. Lab-grown livers could save thousands of lives, especially those in desperate need of liver transplants. It could also save the lives of alcoholics suffering from cirrhosis. (Unfortunately, it could also encourage people to keep bad habits, knowing that they can get replacement organs for their damaged ones.)
    If organs of the body, like the windpipe and the bladder, can be grown now, what is to prevent scientists from growing every organ of the body? One basic problem is how to grow the tiny capillaries that provide blood for the cells. Every cell in the body has to be in contact with a blood supply. In addition, there is the problem of growing complex structures. The kidney, which purifies the blood of toxins, is composed of millions of tiny filters, so a mold for these filters is quite difficult to create.
    But the most difficult organ to grow is the human brain. Although recreating or growing a human brain seems unlikely for decades to come, it may instead be possible to inject young cells directly into the brain, which will incorporate them into the brain’s neural network. This injection of new brain cells, however, is random, so the patient will have to relearn many basic functions. But because the brain is “plastic”—that is, it constantly rewires itself after it learns a new task—it might be able to integrate these new neurons so that they fire correctly.
    STEM CELLS
    One step beyond this is to apply stem cell technology. So far, the human organs were grown using cells that were not stem cells but were cells specially treated to proliferate inside molds. In the near future, it should be possible to use stem cells directly.
    Stem cells are the “mother of all cells,” and have the ability to change into any type of cell of the body. Each cell in our body has the complete genetic code necessary to create our entire body. But as our cells mature, they specialize, so many of the genes are inactivated. For example, although a skin cell may have the genes to turn into blood, these genes are turned off when an embryonic cell becomes an adult skin cell.
    But embryonic stem cells retain this ability to regrow any type of cell throughout their life. Although embryonic stem cells are more highly prized by scientists, they are also more controversial, since an embryo has to be sacrificed in order to extract these cells, raising ethical issues. (However, Lanza and his colleagues have spearheaded ways in which to take adult stem cells, which have already turned into one type of cell, and then turn them into embryonic stem cells.)
    Stem cells have the potential to cure a host of diseases, such as diabetes,heart disease, Alzheimer’s, Parkinson’s, even cancer. In fact, it is difficult to think of a disease in which stem cells will not