Boiko V. Optical properties of synthetic opals infiltrated by biological molecules

The spectral shifts of the photonic stop band upon filling the pores of photonic crystal with aqueous solutions of DNA and amino acids (tryptophan and glycine) were studied. It was shown that introduction of DNA molecules into the pores of photonic crystals increases intensity of the signal and allows detecting luminescence in the visible range. Enhancement of the luminescence is caused by localization of light inside synthetic opals due to interference and multiple scattering in the interglobular space and trapping on structural defects. Due to localization of light, it interacts with biological molecules for longer time, which increases an efficiency of absorption and emission processes. The fluorescent images of DNA molecules and cells on the surface of synthetic opals without labels and dyes were obtained for the first time. It is shown that the introduction of DNA molecules into the pores of PC leads to changes in its conformation due to confinement effects. The content of A and Z forms as well as undefined conformational states increase upon infiltration into PC.