Conformational analysis of single polymer chains in three dimensions by super-resolution fluorescence microscopy

A single polymer chain was directly observed via a super-resolution optical imaging technique, photoactivated localization microscopy (PALM). A hydrophobic rhodamine spiroamide derivative enabled the PALM observation of synthetic polymers. The conformation of a single chain of poly(butyl methacrylate) was investigated with a spatial resolution of 15 nm. The distribution functions of the chain conformation were directly obtained from the high-resolution image of individual chains. Moreover, the three-dimensional structure of individual chains was successfully observed with a lateral spatial resolution of 20 nm and a depth resolution of 40 nm.