Biomedical Engineering Reference
In-Depth Information
electronic, magnetic, catalytic, and other properties that are distinct from those
of atoms/molecules or bulk materials. In order to exploit the special proper-
ties that arise due to the nanoscale dimensions of materials, researchers must
control and manipulate the size, shape, and surface functional groups of NMs,
and structure them into periodically ordered assemblies to create new products,
devices, and technologies or improve existing ones.
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The science of con-
trolling, manipulating, or engineering the properties and utilizing these NMs for
the purpose of building microscopic machinery is termed as nanotechnology.
The control and manipulation process can be done using the “top-down” or
“bottom-up” approach. In the “top-down” approach, large chunks of materials
are broken down into nanostructures by lithography or any other outside force
that impose order on NMs.
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NMs are directly relevant to medicine because of the role of nanoscale phe-
nomena, such as enzyme action, cell cycle, cell signaling, and damage repair.
NMs can be used to create tools for analyzing the structure of cells and tis-
sues from the atomic and cellular levels and to design and create biocompatible
materials at the nanoscale for therapies, diagnostics, and replacements. NMs
can be used to create precisely targeted drugs that are engineered to locate and
sit on specific proteins and nucleic acids associated with the disease and/or dis-
orders. These NMs can also be used to deliver small organic molecules and
peptides at effective sites of action to carry out their function more effectively,
protected from degradation, immune attack, and shielded to pass through barri-
ers that block the passage of large molecules.
At present, NMs are being tested for various biomedical applications to learn
if they can help facilitate sensitive and accurate medical diagnostics as well as
for effective therapeutics. More specifically for drug delivery purposes, the use
of NMs is attracting increasing attention due to their unique capabilities and
their negligible side effects not only in cancer therapy but also in the treatment
of other ailments. Among all types of NMs, biocompatible superparamagnetic
iron oxide NMs or nanoparticles (SPIONs) with proper surface architecture and
conjugated targeting ligands/proteins have attracted a great deal of attention for
drug delivery applications.
Several biological applications of NMs appear to be a few years away from
producing practical products. One example is nanosized semiconductor crystals
called QDs that are being developed for the analysis of biological systems. In
the presence of a light source, these QDs emit specific colors of light depending
upon their size. QDs of different sizes can be attached to biological molecules
allowing researchers to follow these molecules simultaneously during biolog-
ical processes with a single screening tool. When used as disease screening
tool, these QDs offer quicker, less laborious DNA and antibody screening com-
pared with more traditional methods.
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Use of nanoscale particles and coat-
ings is also being pursued for drug delivery systems to achieve improved timed
release of the active ingredients or delivery to specific organs or cell types. New
developments in nanotechnology have led to optical nanosensor systems with
