Novel photoluminescence-enhancing substrates for image formation of   biological objects
  The use of photonic crystals, which were fabricated on the basis of synthetic opals, as substrates for the luminescence microscopy of biological objects has been shown. The spatial distributions of the photoluminescence by DNA clusters excited by 365-nm ultraviolet irradiation on opal surfaces and rough gold substrates have been studied. With the use of blood cells as an example, a possibility for the visualization of biological objects in the case where the nanostructure elements of synthetic opals are applied as labels and image amplifiers has been demonstrated. 
G. I. Dovbeshko, O. M. Fesenko, V. V. Boyko, V. F. Gorchev, S. O.   Karakhin, N. Ya. Gridina, V. S. Gorelik, V. N. Moiseenko
physics.optics cond-mat.mtrl-sci physics.bio-ph