Figure 4: Optical design used to monitor the biological viablity
of the cells using the nanoporous polymer film. On the right are
the representative spectra corresponding to the each process.
(a) To measure the transmitted light from the sample,
illumination (light source) and observation (detector) are
aligned on the same optical path and the corresponded spectra
shows a broad shape which is not suitable for biological
observation. (b) To measure the diffracted light, the
observation (detector) is placed in the position of the
diffracted light path, from the sample normal, leading to a
sharp spectrum signal. (c) Seeding the cells on the sample
surface introduces a scattering effect as the cells scatter some
light out of the diffracted light path and the intensity of
spectrum decreases. (d) Cell death causes the cells to detach
from the sample surface and the intensity of spectrum increases.