Chemistry Reference
In-Depth Information
18
16
PEG-MSH-NDP
PEG
14
12
10
8
6
4
2
0
Fig. 20 Biodistribution of HAuNs targeted with NDP-MSH-PEG-HAuNs and untargeted,
i.e., functionalized with PEG. Data are plotted as % of injected dose per gram of tissue. Mean
FSD (
n
ΒΌ
5). *,
P
<
0.01. Figure adapted from [
105
]
irradiation selectively addresses the AuNPs based on their size-dependent physical
properties, such as SPR or X-ray radiosensitization. The potential applications that
arise from these opportunities will be discussed in the following sections by means
of selected examples.
5.2 AuNPs as Contrast Agents in Molecular Imaging and
as Therapeutic Agents
Molecular imaging is an emerging field integrating molecular biology, chemistry,
and radiology in order to gain understanding about biological processes and to
identify diseases based on molecular markers, which appear earlier than the clinical
symptoms [
106
]. The application of AuNPs in this area is increasing rapidly and
offers excellent prospects for the development of new strategies for the diagnosis
and treatment of cancer [
107
]. The reasons for this increasing attention to gold
nanoconstructs are many: their size-dependent and shape-dependent plasmonic
properties enable them to absorb and scatter light in the visible to NIR region,
which may render them suitable for image-guided therapy and photothermal ther-
apy (PTT). Significant synthetic advances now allow the design of AuNPs with
highly controlled geometry, surface charge, physicochemical properties, and the
decoration of their surfaces with polymers and bioactive molecules in order to
improve biocompatibility and to achieve active targeting. This is stimulating the
development of a diverse range of nanometer-sized objects that can recognize
cancer tissue [
107
]. The use of the unique optical properties of AuNPs presents a
