fiber scaffolds were labeled by physical absorption of rhodamine 6G from an
aqueous solution.
Hematoxylin-eosin and Masson trichrome staining: The vascular constructs were
cut andfixed in formalin solution and then infiltrated with molten paraffin. The
infiltrated tissues were embedded into paraffin blocks and cut into 5– 6 lm sections.
Then the sections were rehydrated. Standard hematoxylin and eosin staining [ 33 ]
was carried. Collagen secretion by HASMCs was assessed on deparaffinized sec-
tions using a Masson’s trichrome staining kit according to a standard protocol [ 34 ].
4.2.5 Characterization................................
Confocal and epi-fluorescence imaging was carried out using an Olympus Fluoview
FV1000 confocal laser scanning microscope.ImageJwas used for 3D recon-
struction and analysis of the confocal and epi-fluorescence images. Bright-field
optical micrographs of histological samples were acquired on an Olympus FSX100
system. HMXST Micro-CT X-ray imaging system was used for imaging metal
interconnects in synthetic vascular construct.VGStudio MAXwas used for 3D
reconstruction and analysis of the micro-CT images. LIVE/DEAD®Viability/
Cytotoxicity Kit was used to evaluate hippocampal neuron viability on days 7, 14
and 21 of the culture. CellTiter 96®AQueous One Solution Cell Proliferation Assay
was used for evaluate the mitochondrial metabolic activity of cardiomyocyte on
days 2, 4, 6, 8, 10 and 12 of the culture.
4.2.6 Electrical Measurement..........................
The nanowire FET conductance and transconductance were measured and cali-
brated in 1PBS as described previously [ 18 ]. For nanowire FET stability tests,
nanoES were maintained under neuron culture conditions for predetermined
intervals. Electrical transport measurements and recordings were obtained in culture
medium (for neuron), tyrode solution (for cardiac construct) and PBS solution with
different pH value (for vascular construct) by home-built amplifiers as described
previously [ 18 , 20 ].
4.3 Results and Discussion................................
4.3.1 NanoES Characterization.........................
We have designed two nanoES (Fig.4.5) that are free-standing,flexible and contain
similar components. 3D self-organized nanoES (Fig.4.5a) were made by electron
46 4 Three-Dimensional Macroporous Nanoelectronics...