Biomedical Engineering Reference
In-Depth Information
(A)
Graphene
SERS
Cell
uptake
Au
coating
Detect
stem cell
differentiation
NP
(B)
Cardiac MRI
Magnetic
Au
coating
Cell
uptake
Monitor
stem cells
in situ
NP
(C)
Detect
Au coated
Cationic
dendrimer
coating
DNA
siRNA
Cell
uptake
Tr ansfected
cells
Magnetic NP
Figure 9.2
Gold-coated nanoparticles (NPs) for detection and imaging of stem cells. (A) Graphene
oxide encapsulated gold NPs internalized by undifferentiated neural stem cells show a strong C=C
Raman band centered at 1656 cm
−1
in surface enhanced Raman spectroscopy (SERS), whereas the
differentiated cells show a low intensity signal. These NPs can be used for
in situ
monitoring of the
differentiation state of stem cells. (B) Gold-coated magnetic NPs can be used for safe
in situ
monitoring
of stem cells using cardiac magnetic resonance imaging. The gold coating reduces toxicity of the
superparamagnetic iron oxide core used as a contrast agent. (C) The gold-encapsulated magnetic NPs
are coated with a water-soluble cationic dendrimer for complexation with the negatively charged
siRNA or plasmid DNA for safe gene transfection of stem cells. The NPs can be used for safe gene
delivery and monitoring of the transfected stem cells.
of SPION-labeled ESCs resulted in a significant improvement in heart function in mice
[126]. Shah
et al
. synthesized multimodal magnetic core-shells (MCNPs) with a magnetic
core and a gold shell for imaging and immobilization of small interfering RNA (siRNA;
Figure 9.2B) [123]. The multimodal NPs were prepared by coating the water-soluble MCNPs
with a cationic polyamine dendrimer for complexation with the negatively charged siRNA
or plasmid DNA (pDNA; Figure 9.2C) [123]. The gold shell of the NPs, which is biocom-
patible with stem cells, provides a large surface area for functionalization and complexation
with anionic nucleic acids, and dark-field imaging can be used to monitor cell differentiation.
The magnetic core of the NPs in Figure 9.2C allows
in situ
monitoring of differentiation of
NSCs [123].
To evaluate the proximity and adhesion of transplanted MSCs to metallic implants
in vivo
, Tautzenberger
et al
. synthesized phosphonate-functionalized NPs and evaluated
their uptake by MSCs [125]. Unlike carboxy- or amino-functionalized NPs, phosphonate-
functionalized NPs firmly attach to the surface of titanium implants. They reported robust
intracellular incorporation of the NPs in MSCs with the use of transfection agents [125].
They also reported that the incorporation of NPs did not affect viability of MSCs and the
cells underwent osteogenic, chondrogenic or adipogenic differentiation in an appropriate
medium [125]. These studies clearly demonstrate that NPs are potentially useful for tracking
