Optical super-resolution imaging by high-index microspheres embedded in elastomers

We demonstrated feasibility of super-resolution imaging through high-index microspheres embedded in transparent elastomers. We performed imaging, with resolution improvement by a factor of two, by using implanted barium titanate glass microspheres (diameters similar to 30-150 mu m and refractive index similar to 1.9-2.1) in a thin film of polydimethylsiloxane elastomer placed over the specimen. Microsphere-assisted imaging technique is a promising candidate for applications in cancer research. As a proof-of-principle, we used microsphere-assisted imaging technique for the observation of radiation-induced gamma-H2AX foci formation in U87 human glioblastoma cells irradiated by clinical proton beams. (C) 2014 Optical Society of America