The Emerging Applications of Graphene Oxide and Graphene in Tissue Engineering - Biomimetics: Advancing Nanobiomaterials and Tissue Engineering - page 286

( a )

Three days Two weeks Three weeks

Glass Graphene Glass Graphene Glass Graphene

( c )

300

One month

( b )

Glass Graphene

200

100

0

Glass Graphene

( d )

GFAP
TUJ1

Glass Graphene

50

30

10

Glass Graphene

GFAP TUJ1 DAPI GFAP TUJ1 DAPI

Figure 12.3 Enhanced differentiation of human neural stem cells (hNSCs) on
graphene substrates compared to the glass slide (control) substrates. (a) Phase-
contrast images of differentiated hNSCs on both graphene and glass slides after
three days, two weeks, and three weeks of differentiation. The cells on the glass
slide gradually detached from the substrate. (b) Phase-contrast (top row) and
fl uorescence (bottom row) images of differentiated hNSCs on the graphene
and glass substrates after one month of differentiation. Differentiated hNSCs
were stained with DAPI (blue), GFAP (red), and TUJ1 (green) to reveal cell
nuclei, astroglial cells, and neural cells, respectively. (c) Cell number per area on
graphene and glass substrates after one month of differentiation indicating more
cells on the graphene than on the glass slide (p 0.001). (d) Immunoreactive glia

and neurons stained by GFAP (red) and TUJ1 (green), respectively, on graphene
and glass substrates. Note that more glia cells were observed on the glass slides
compared to graphene substrates, while more neuron cells were present on
the graphene than on the glass substrate (p

<

< 0.05). All scale bars are 200 m m.

Reproduced with permission from [38].

(Figure 12.3). In addition, stem cells on the graphene substrates differenti-
ated into more neuron cells and less glia cells compared to those on the
glass slides. These phenomena were attributed to the strong cell adhesion
to graphene, which led to the retention of more cells on graphene than
on the glass slide over long culture times [84]. Successful use of human
neural stem cells for the neuron generation and brain repair strongly
depends on higher differentiation of these cells toward neurons rather