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.