Biomedical Engineering Reference
In-Depth Information
that there will be a minimal signal from PA of 2°Ab-QD on the cell surface.
PA of the 2°Ab-QD is possible because the 2°Ab is not only specific for the
cell membrane surface proteins but is also specific to the anti-HER2/neu that
were used to label the membrane proteins in tubes 3 and 4. This process can
be used to minimize PA for in vitro diagnostics of cells, proteins, and other
biomolecules using NMs.
3.3.4 Electrostatic Charge-charge Interaction
Other schemes that have been used in biosensors for infectious disease diag-
nostic devices include the electrostatic interactions.
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For example, silver
NPs in polystyrene sulfonate/polyacrylic acid capsules were coated with avidin
via electrostatic interactions and used as label for electrochemical detection of
E. coli
DNA hybridization through a biotin-avidin interaction.
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Their use of capsules of silver NPs (AgNPs) was reported to: (1) lower the
detection limit as compared to other AgNPs-based assays; (2) lower the detec-
tion limit in comparison to many hybridization assays using other NMs; and (3)
approach the sensitivity of chemiluminescence, which is reported to be one of
the most sensitive DNA detection methods using AgNPs.
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The group of Meyer has exploited the specific biotin-avidin interaction
when they used commercially prepared magnetic beads coated with strepta-
vidin for the detection of
Yersinia pestis
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and
Francisella tularensis.
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The
detection principle used anti-Ft or anti-YPFI Abs for capturing the Ft or YPFI
antigen. Biotinylated Abs were coupled with the streptavidin in magnetic beads.
Binding resulted to a change in the induced magnetic field. These streptavidin-
modified magnetic beads showed promise in the development of easy, fast, and
highly sensitive biosensor for the detection and quantification of the infectious
diseases mentioned.
3.4 APPLICATIONS OF BIOCOMPATIBLE NMS
Biomedical applications of NMs in the field of medicine and the life sciences
research in general are growing rapidly. Nanomedicine not only aspires to
develop a valuable set of research tools and devices,
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but also garners a
lot of attention for its possible commercial applications in the pharmaceuti-
cal industry that may include targeted drug delivery systems, new therapies,
and in vivo imaging.
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NM-based neuro-electronic interfaces, nanobiosensors,
NMs-based strip immunoassays, and nanoelectronic-based sensors are among
the on-going and active areas of research in nanotechnology.
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Going into the
molecular level, nanotechnology holds promise that cell repair can be carried
out by molecular nanomachines that could revolutionize medicine and the med-
ical field. Nanomedicine sales reached 6.8 billion dollars in 2004 with over 200
companies and 38 products worldwide putting a minimum of 3.8 billion dollars
in nanotechnology R&D investment every year.
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This unprecedented growth
