andfilled by polylysine solution for surface modification overnight at 37 °C. Finally,
the chamber wasfilled with culture medium for cell culture. Hippocampal neurons
were prepared using a standard protocol [ 28 ]. After 1 day, medium was changed to
Neurobasal™medium supplemented with B27 Serum-Free Supplement, Glutamax™
and 0.1% Gentamicin reagent solution [ 29 ]. A gas-permeable/water-impermeable
membrane covers were used to avoid evaporation while allowing for diffusion of
gases (Fig.4.2d).
Cardiomyocyte culture: Hybrid scaffolds (Fig.4.3b) consisting of nanoES
(Fig.4.3a, g) sandwiched between two electrospun PLGAfiber layers were used in
all experiments. The device chip was wire-bonded (Fig.4.3c, h), and assembled
with a petri-dish (Fig.4.3d). The device chamber was cleaned by O 2 plasma and
sterilized by UV-light and ethanol solution. The hybrid scaffolds were coated with
fibronectin/gelatin solution overnight prior to cell seeding. Cardiac cells were
isolated from intact ventricles of 1 to 3-day-old neonatal Sprague/Dawley rats as
described elsewhere [ 30 ]. The cardiac cells werefinally seeded with 5–10 mg/mL
Matrigel™ontofibronectin/gelatin coated PLGA/nanoES at an initial cell density of
3 – 6 107 cm−^2 (Fig.4.3e). After 1–2 days, the cell-seeded nanoES was manually
folded into a construct, and was maintained in incubator for an additional 3–8 days
Fig. 4.2 Chip assembly for neuronal 3D cultures.aA scrolled-up nanoES chip was sterilized and
assembled onto a temperature controlled chip carrier.bA shallow PDMS chamber (dashed box)
was cleaned and placed over the assembled chip.cA glass ring wasfixed over the PDMS
chamber.dA gas-permeable, water-impermeable membrane cover was used for neuron cultures
4.2 Experimental 43