Biomedical Engineering Reference
In-Depth Information
deleterious sequelae occur. For patients suspected of experiencing sleep apnea,
in vivo sensors could constantly monitor blood concentrations of oxygen and
cardiac function to detect problems during sleep. In addition, cardio-specific anti-
bodies tagged with nanoparticles may allow doctors to visualize heart movement
while a patient experiences sleep apnea to determine both short- and long-term
effects of apnea on cardiac function.
Detection and Treatment of Atherosclerotic Plaques
in the Arteries
A key feature of the atherosclerotic process is the angiogenic expansion of the vasa
vasorum in the adventitia, which extends into the thickening intimal layer of the
atheroma in concert with other neovessels originating from the primary arterial
lumen. Magnetic resonance molecular imaging of focal angiogenesis with integrin-
targeted paramagnetic contrast agents has been reported with PFC nanoparticles
and liposomes. Site-targeted PFC nanoparticles also offer the opportunity for local
drug delivery in combination with molecular imaging.
The diagnosis and treatment of unstable plaque is an area in which nanotechnology
could have an immediate impact. Fibrin-specific PFC nanoparticles may allow the
detection and quantification of unstable plaque in susceptible patients, which may
be an important feature of future strategies to prevent heart attacks or stroke.
Research is under way using probes targeted to plaque components for noninvasive
detection of patients at risk. In an extension of this approach, targeted nanoparticles,
multifunctional macromolecules, or nanotechnology-based devices could deliver
therapy to a specific site, localized drug release being achieved either passively (by
proximity alone) or actively (through supply of energy as ultrasound, near-infrared,
or magnetic field). Targeted nanoparticles or devices could also stabilize vulnerable
plaque by removing material, for example, oxidized low-density lipoproteins.
Devices able to attach to unstable plaques and warn patients and emergency medi-
cal services of plaque rupture would facilitate timely medical intervention.
Monitoring for Disorders of Blood Coagulation
Patients would benefit greatly from nanotechnological devices that could monitor
the body for the onset of thrombotic or hemorrhagic events. Multifunctional devices
could detect events, transmit real-time biologic data externally, and deliver antico-
agulants or clotting factors to buy critical time.
A gold nanoparticle-based simple assay has been described that enables the
visual detection of a protease (Guarise et al.
2006
). The method takes advantage of
the high molar absorptivity of the plasmon band of gold colloids and is based on
the color change of their solution when treated with dithiols. Contrary to the native
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