Rhodamine Spiroamides for Multicolor Single-Molecule Switching Fluorescent Nanoscopy

VLADIMIR N. BELOV; MARIANO L. BOSSI; JONAS FOLLING; VADIM P. BOYARSKIY; STEFAN W. HELL

CHEMISTRY-A EUROPEAN JOURNAL

Wiley-VCH Verlag 10762 GmbH&Co. KGaA,

Lugar: Weinheim; Año: 2009 vol. 15 p. 10762 - 10776

0947-6539

The design, synthesis, andevaluation of new rhodamine spiro-ACHTUNGTRENUNGamides are described. These moleculeshave applications in optical nanoscopybased on random switching of the fluorescentsingle molecules. The newmarkers may be used in (co)localizationstudies of various objects and their(mutual) positions and shape can bedetermined with a precision of a fewtens of nanometers. Multicolor staining,good photoactivation, a largenumber of emitted photons, and selectivechemical binding with amino orthiol groups were achieved due to thepresence of various functional groups on the rhodamine spiroamides. Rigidizedsulfonated xanthene fragmentfused with six-membered rings, N,N’-bis(2,2,2-trifluoroethyl) groups, and acombination of additional doublebonds and sulfonic acid groups withsimple aliphatic spiroamide residueprovide multicolor properties and improveperformance of the rhodaminespiroamides in photoactivation andbioconjugation reactions. Having both essential parts of the photoswitchableassembly—the switching and the fluorescent(reporter) groups—combinedin one chemical entity make this approachattractive for further development.A series of rhodamine spiro-ACHTUNGTRENUNGamides is presented along with characterizationsof their most relevant propertiesfor application as fluorescentprobes in single-molecule switchingand localization microscopy. Opticalimages with resolutions on the nanometerscale illustrate the potential ofthe labels in the colocalization of biologicalobjects and the two-photon activationtechnique with opticalsectioning.