Most of the recent super-resolution imaging techniques developed for biology are based on fluorescence properties which generally require toxic dyes. We show how super-resolution can be obtained without dyes by simply adding 20-micrometer-diameter dielectric spheres on the sample under a microscope objective. The microsphere behaves as a non-classical lens, collecting evanescent waves in a full-field imaging process. Resolutions of up to between /5 and /7 can be reached in air and in immersion, respectively. For translucent biological samples, a dark-field optical setup is proposed. Performance of the label-free super-resolution technique is demonstrated through the imaging of fixed nerve sections from a mouse embryo brain.