Mechanical cues in cellular microenvironment are central in directing a
class of cellular behaviors such as the dynamic of cell adhesion, migration,
and differentiation. Several advanced optical techniques, such as
structured-illumination nano-profilometry (SINAP), have been developed for a
better resolution of these dynamic processes. These techniques however
require culturing cells on materials of refractive index close to that of
glass, while most studies regarding the effects of mechanical cues on
cellular dynamics were conducted on hydrogel-based substrates. Here we
report the development of culturing substrates of tunable rigidity and
refractive index suitable for SINAP studies. Polyvinyl chloride (PVC)-based
substrates were mixed with a softener called Di(isononyl)
Cyclohexane-1,2-Dicarboxylate (DINCH) and cured by heating. The volume
ratios of PVC to DINCH were varied from 1:1 to 3:1. The Young’s modulus of
the resulting substrates ranged from 18 kPa to 40 kPa. The yielded
refractive indices of the composite substrates as measured by phase contrast
tomography ranged from 1.47 to 1.53. Human lung adenocarcinoma cells CL1-5
were cultured on the composite substrates and cell viability was examined
using the MTT assay. The dynamics of cell adhesion and filopodia activities
were examined using SINAP. Preliminary results suggest that PVC based
culturing substrates have a great potential in the application of SINAP
based studies.