Biomedical Engineering Reference
In-Depth Information
Reduction
Oxidation
Undifferentiated
e
-
PR
PR
Differentiated
Au
A
Cr
Cr
SiO
2
e
-
(C)
(D)
(E)
5
60
No cell
Undifferentiated mNSC
No cell
40
20
0
Undifferentiated mNSC
4
Differentiated mNSC
Differentiated mNSC
3
2
100 nA
-20
E
pc
= 154 mV
1
-40
0
0.6 .4
0.2
0.0
-0.2
-0.4
-0.4
-0.2
0.0
Voltage/mV
0.2
0.4
E/V vs. Ag/AgCl
Figure 7.11
Electrochemical signals from undifferentiated and differentiated neural stem cells (NSCs).
(A) Schematic illustration of the detection strategy for electrochemical signals of undifferentiated/
differentiated single NSCs. (B) Picture of microelectrodes arrays. White squares indicate undifferentiated/
differentiated NSC adhered on photoresist-removed area where graphene oxide (GO) encapsulated gold
nanoparticles (GNP) were immobilized between two metal electrodes prior to cell seeding. (C) Cyclic
voltammetry of undifferentiated/differentiated NSCs attached on a microgap. (D) Intensities of cathodic
peaks at 154 mV obtained from a bare GO-GNP modified microgap: electrodes with undifferentiated and
differentiated NSCs. (E) Intensity-voltage curve achieved from undifferentiated/differentiated NSCs showing
the differences between current intensities and patterns induced by the electrons that passed through cells on
GO-GNPs bridging a microgap. Figure reproduced with permission from: ref. 63, © 2013 Elsevier.
Control 1 (glass)
Control 2 (NPs)
Control 3 (GO)
EXP. (NPs+GO)
(A)
Substrate A
Substrate B
Substrate C
Substrate D
(B)
Neurons
Neural stem cell
Neuronal differentiation
and axonal alignment
Figure 7.12
Schematic diagram depicting the influence of nanoparticle (NP) monolayers coated
with graphene oxide (GO) on the alignment of the axons extending from human neural stem cells
(NSCs), and the differentiation of NSCs into neurons. (A) Different control and experimental
conditions for differentiating NSCs into neurons where: substrate A is glass with a positively charged
surface; B is glass with a monolayer of positively charged NPs; C is glass with a positively charged
surface and coated with GO; D is glass with a monolayer of positively charged NPs coated with GO.
(B) Neural stem cells cultured and differentiated on substrate D with a monolayer of NPs coated with
GO show enhanced neuronal differentiation and axonal alignment. The differentiated NSCs (orange)
and the NPs-coated with GO (blue) in the scanning electron microscopy image have been pseudocolored
to enhance the contrast. (Inset) Close-up image showing the axons aligned on a monolayer of NPs
coated with GO. Figure reproduced with permission from: ref. 64, © 2013 John Wiley & Sons.
