Stimulated Emission Depletion Microscopy Resolves Nanoparticle Assembly on a Porous Membrane Surface

Abstract

Stimulated emission depletion microscopy—depending on the nature of fluorophore and sample, depletion laser power, and other experimental conditions—provides diffraction unlimited lateral resolution in the range of 20- 100 nm. In this paper, a detailed description of such a microscope along with one of the possible imaging schemes is provided. Application of such a microscope in resolving self assembly of polymeric nanoparticles on porous alumina membrane in wet condition is demonstrated. STED microscopy resolves formation of loose linear to quasi polygonal self-assembly patterns on the membrane surface. Possible reasons for the formation of such self assembly patterns are provided.