We embedded carbon nanotubes (CNTs) in
mouse embryoid bodies (EBs) for modulating mechanical
and electrical cues of the stem cell niche. The CNTs
increased the mechanical integrity and electrical conduc-
tivity of the EBs. Measured currents for the unmodified
EBs (hereafter, EBs) and the EBs-0.25 mg/mL CNTs
were 0.79 and 26.3 mA, respectively, at voltage of 5 V.
The EBs had a Young’s modulus of 20.9 ± 6.5 kPa,
whereas the Young’s modulus of the EB-0.1 mg/mL
CNTs was 35.2 ± 5.6 kPa. The EB-CNTs also showed
lower proliferation and greater differentiation rates com-
pared with the EBs as determined by the expression of
pluripotency genes and the analysis of EB sizes.
Interestingly, the cardiac differentiation of the EB-CNTs
was significantly greater than that of the EBs, as con-
firmed by high-throughput gene analysis at day 5 of cul-
ture. Applying electrical stimulation to the EB-CNTs spe-
cifically enhanced the cardiac differentiation and beating
activity of the EBs.

• Carbon nanotubes embedded in embryoid bodies direct cardiac differentiation