Biomedical Engineering Reference
In-Depth Information
Chapter 1
Iron Oxide Nanoparticles and Derivatives
for Biomedical Imaging and Application
in Cancer Diagnosis and Therapy
Mehmet V. Yigit and Zdravka Medarova
Abstract
Imaging-capable nanoparticulate contrast agents for cancer diagnosis
and small RNA-based tumor therapy have been an emerging field in molecular
imaging and pharmaceutical sciences. One example of such agents includes mag-
netic nanoparticles (MN), which have traditionally been utilized as contrast agents
for Magnetic Resonance Imaging. The probes typically consist of a dextran-coated
superparamagnetic iron oxide core (for MRI), labeled with Cy5.5 dye (for near-
infrared in vivo optical imaging), coated with targeting-peptides for receptor-
mediated uptake by specific cell types and conjugated to synthetic small interfering
RNA (siRNA) molecules as therapeutic agents. The potential of these nanoparticles
as MRI contrast agents for tumor imaging and delivery modules for small
interfering RNA has been investigated. Furthermore, the feasibility of combining
the imaging and delivery capabilities of these nanoparticles for the tracking of
siRNA bioavailability has been explored. The versatile functionalization potential
of MN has allowed controlling properties of the agents, such as uptake mechanism
and target organ distribution. The tumoral accumulation of MN-siRNA results in a
remarkable level of target-gene down-regulation. Repeated treatment with MN-
siRNA targeting the tumor-specific anti-apoptotic gene, birc5, leads to the induc-
tion of apoptosis in the tumors and an overall reduction in tumor growth rate.
Bioconjugated MNs were also used for biosensing application for several metabol-
ically important compounds and processes. A second generation of nanoparticles,
which combine the capability for high-resolution MRI with detection by ultrasen-
sitive surface enhanced Raman scattering has been tested in silico and in vivo.
Different types of magnetic nanoparticles have been used for therapy of cancer by
Magnetic Fluid Hyperthermia.
