Medical technology: New frontiers in health care 145autoimmune diseases such as lupus. At this point, however, potential applications of nanotech-
nology are at the research stage. Current projects include the following:
◆ Nanoscale coatings for medical devices
◆ Nanotankers that supply tissues with oxygen
◆ Nanocontrast agents that illuminate speciic cells in diseased tissue
◆ Nanoscafolding that aid the three-dimensional growth of artiicial organs
◆ Nanoscale cancer killing machines that travel through the body and selectively poison cancer
cells
◆ Nanosensors that analyze the condition of tissue
◆ Nanosurgibots that perform surgery at the cellular level
Although major technical obstacles have yet to be overcome, the potential for nanotechnological
applications appears limitless, and future nanomedicine is expected to be instrumental in diag-
nosing and treating cancer.
9 Another promising ield, stem cell research, could eventually beat cancer and many debili-
tating genetic diseases. hanks to embryonic stem cells, a single cell consisting of a sperm cell and
an egg blossoms into a complex human embryo, with more than 200 diferent types of cells. In
their DNA, these master cells contain the complete instruction manual for life, and they are
responsible not only for an embryo’s development, but for the renewal, regeneration, and repair
of cells throughout an individual’s lifetime. Since the late 1980s, bone marrow stem cells have suc-
cessfully treated leukemia. More recently, they have been used for other blood-related disorders,
metabolic and immune deiciency diseases, and cancers of the brain, kidneys, and breast, among
others. International registries can match suitable donors with patients in need of bone marrow
transplants. Because stem cells know exactly where to go when they are needed in the body and
can live forever if frozen, the sky is the limit in how they could be used.
10 here are two types of stem cells: adult, or somatic, stem cells, which are found in existing
tissue, and embryonic stem cells. Embryonic stem cells can be extracted only from unused in
vitro embryos at fertility clinics or cloned embryos, which makes this practice the subject of
heated debate. Stem cell research is generally considered vital in principle, and the United States
government funds research with embryos created before 2001. However, individual states are
responsible for regulation, and laws vary widely, from an outright ban to a policy of open encour-
agement. One proposal for getting around the ethical issue is to collect embryonic stem cells from
the umbilical cord and to store and bank them for future use. In the meantime, it will take medical
researchers years to learn how stem cells really work before they can produce viable medical
cures.
11 When Dr. Christiaan Barnard performed the irst heart transplant in 1967, it seemed like a
miracle. Back then, few could imagine how commonplace organ transplants would become and
how many lives they would save. When James Watson and Francis Crick discovered the double
helix structure of DNA in 1953, who would have thought that 50 years later, the Human Genome
Project would complete its mapping of 99% of the human genome? When the irst artiicial heart
was implanted in Barney Clark in 1982, who would have believed that the cumbersome machin-
ery used in that experimental operation would evolve into two pounds of plastic, polyurethane,
and metal engineered to be resistant to clot formation? Whether it’s artiicial heart valves or pace-
makers, laser eye surgery, artiicial bionic limbs, biocomposite skin for burn victims, or any num-
ber of medical wonders, technology is changing the face of medicine.
12 As technology proceeds to break through new barriers, it will change lives and life itself.
Who can guess where it will take us next?After reading
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