28-03-2012, 04:07 PM
Understanding Nanodevices
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What Is Nanotechnology?
A nanometer is a billionth of a meter. Its difÞcult to imagine anything so small, but think of
something only 1/80,000 the width of a human hair. Ten hydrogen atoms could be laid side-byside
in a single nanometer.
Nanotechnology is the creation of useful materials, devices, and systems through the manipulation
of matter on this miniscule scale. The emerging Þeld of nanotechnology involves scientists from
many different disciplines, including physicists, chemists, engineers, and biologists.
There are many interesting nanodevices being developed that have a potential to improve cancer
detection, diagnosis, and treatment.
Nanotechnology Plays by Different Rules
Much of todays nanoscale research is designed to reach a better understanding of how matter
behaves on this small scale. The factors that govern larger systems do not necessarily apply at the
nanoscale. Because nanomaterials have large surface areas relative to their volumes, phenomena
like friction and sticking are more important than they are in larger systems.
Designing Nanodevices for Use in the Body
Other challenges apply speciÞcally to the use of nanostructures within biological systems.
Nanostructures can be so small that the body may clear them too rapidly for them to be effective in
detection or imaging. Larger nanoparticles may accumulate in vital organs, creating a toxicity
problem. Scientists will need to consider these factors as they attempt to create nanodevices the
body will accept.
Nanopores
Another interesting nanodevice is the nanopore. Improved methods of reading the genetic code will
help researchers detect errors in genes that may contribute to cancer. Scientists believe nanopores,
tiny holes that allow DNA to pass through one strand at a time, will make DNA sequencing more
efÞcient. As DNA passes through a nanopore, scientists can monitor the shape and electrical
properties of each base, or letter, on the strand. Because these properties are unique for each of the
four bases that make up the genetic code, scientists can use the passage of DNA through a
nanopore to decipher the encoded information, including errors in the code known to be associated
with cancer.
Dendrimers as Cancer Therapy
A single dendrimer can carry a molecule that recognizes cancer cells, a therapeutic agent to kill
those cells, and a molecule that recognizes the signals of cell death. Researchers hope to
manipulate dendrimers to release their contents only in the presence of certain trigger molecules
associated with cancer. Following drug release, the dendrimers may also report back whether they
are successfully killing their targets.