(676e) Dendrimer Based Nanoprobes for Super-Resolution Fluorescence Microscopy (STORM)

Recent advances in imaging and single molecule fluorescence microscopy have enabled the direct observation of biological processes at the molecular level. Super-resolution imaging techniques such as photoactivated localization microscopy (PALM)and stochastic optical reconstruction microscopy (STORM) have been developed using photoswitchable fluorescent proteins and organic dyes. However, there is a strong need for development of bright and photostable nanoscale probes for biological imaging to further push the limits of high resolution microscopy.

In this work, we demonstrate the use of dye-conjugated dendrimers as nanoscale imaging probes for high-resolution fluorescence microscopy, which overcomes the diffraction limited optical resolution and enables imaging at a higher resolution compared to standard organic dyes. Generation-5 polyamidoamine (PAMAM) dendrimers were modified to contain multiple fluorescent dyes, and the photophysical properties of these nanoprobes were characterized using single molecule fluorescence microscopy, total internal reflection microscopy (TIRF-M). For dendrimer-based imaging probes, we observed enhanced photophysical properties including highly extended photobleaching lifetimes and enhanced localization precision compared to single organic dyes such as Cy5 or Alexa flour 657. Using this new class of chemical imaging probes, we were able to achieve a 10 nm spatial resolution for reconstructed images from dSTORM, which surpasses the spatial resolution of single organic probes (25 nm).