Nanotechnology and nanomedicine in cardiovascular therapy - Biomaterials and Devices for the Circulatory System - page 248

to full-thickness dermal wounds, angiogenesis was signifi cantly higher along
with the level of maturity when compared to that induced by the application
of VEGF (Trentin et al. , 2006).
Therapy of CVD has become a highlight of nanomedicine research and
may play a central role in disease prevention and treatment.

9.2 Nanomedicine in cardiovascular imaging

There has been a signifi cant improvement in platform technology for
imaging modalities for magnetic resonance imaging (MRI), nuclear-
computed tomography imaging, and optical and ultrasound imaging. In
addition our increased understanding of specifi c cellular markers has pro-
vided novel targets for these modalities over the past 10 years. Added to
this the potential of nanotechnology, the area of CVD imaging is an
extremely exciting one.

9.2.1 Nuclear/positron emission tomography imaging

The general approach of nuclear (gamma/SPECT (single photon emission
computed tomography)) imaging and positron emission tomography (PET),
for example, has been to utilise very small tracer quantities of contrast
agents (e.g. radionuclide-labelled antibodies, peptides or small molecules)
rather than large payload particles. For example, folate receptor-targeted
polymeric shell cross-linked nanoparticles containing 64 Cu have been
recently used for PET imaging of tumours. Other approaches for charac-
terising atherosclerosis include imaging of apoptosis by annexin-
phosphatidyl serine targeting, unstable carotid plaque imaging with meta-
bolic (fl uorodeoxyglucose) readouts, and macrophage chemotaxis imaging
(Blankenberg et al. , 2002; Rudd et al. , 2002; Britz-Cunningham and
Adelstein, 2003; Rossin et al. , 2005).

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9.2.2 Optical imaging

10 nm) fl uorescent semiconductor nanocrystals
which possess unique luminescent properties compared with more estab-
lished organic dyes and fl uorescent proteins. Their fl uorescence emission is
stable and dependent on particle size. Cadmium selenium-zinc sulphide
quantum dots have been used to visualise capillaries hundreds of microme-
tres deep through the skin of living mice. Cadmium-based quantum dots
have also be used to image cerebral vasculature. Methoxy-PEGylated
quantum dots were used to visualise arterioles and capillary networks in
mouse hind limb skeletal muscle (Akerman et al. , 2002; Larson et al. , 2003;
Bateman et al. , 2007; J.D. Smith et al. , 2007).

Quantum dots are small ( <