Quantification of combinatorial
effects of nanotopographical and
biochemical cues on synaptic maturation and stability. (A) (Left)
Confocal micrographs displaying neuronal PSD-95 expression on 3D NPs
functionalized with PDLO and PDL and on a planar Au surface functionalized
with PDLO. (Right) Quantification of PSD-95 protein expression is
performed by processing the images with the granulometric filter method.
The magenta and green cross sections indicate the fluorescence and
the corresponding filtered intensities, respectively. The start and
the end positions of the cross sections are read from the left (0
μm) to the right (40 μm). The yellow dotted grids denote
the regions of 3D NPs. The position of the PSD-95 puncta was defined
above an arbitrary offset on the filtered fluorescence scale, that
is, 30, indicated by the black dotted lines. All scale bars represent
30 μm in images on the left and 10 μm in images on the
right. (B) Bar graph showing the quantified combinatorial effects
of nanotopographical cues (3D NPs, planar Au, and planar glass surfaces)
and biochemical cues (PDLO and PDL) conferred by the normalized numbers
of PSD-95 ensembles (density). PSD-95 puncta is significantly higher
in neurons grown on PDLO/NPs (1 ± 0.048) compared to (0.52 ±
0.076, 0.63 ± 0.083, 0.59 ± 0.088, 0.57 ± 0.077, and
0.59 ± 0.068) for neurons grown on PDL/NPs, PDLO/planar Au, PDLO/planar
glass, PDL/planar Au, and PDL/planar glass, respectively. (n = 4, **p < 0.01, ANOVA).