title: Aptamer Stainings for Super-resolution Microscopy.
abstract: Fluorescence microscopy is an invaluable tool to visualize molecules in their biological context with ease and flexibility. However, studies using conventional light microscopy have been limited to the resolution that light diffraction allows (i.e., ~200 nm). This limitation has been recently circumvented by several types of advanced fluorescence microscopy techniques, which have achieved resolutions of up to ~10 nm. The resulting enhanced imaging precision has helped to find important cellular details that were not visible using diffraction-limited instruments. However, it has also revealed that conventional stainings using large affinity tags, such as antibodies, are not accurate enough for these imaging techniques. Since aptamers are substantially smaller than antibodies, they could provide a real advantage in super-resolution imaging. Here we compare the live staining of transferrin receptors (TfnR) obtained with different fluorescently labeled affinity probes: aptamers, specific monoclonal antibodies, or the natural receptor ligand transferrin. We observed negligible differences between these staining strategies when imaging is performed with conventional light microscopy (i.e., laser scanning confocal microscopy). However, a clear superiority of the aptamer tag over antibodies became apparent in super-resolved images obtained with stimulated emission depletion (STED) microscopy.
authors.affiliation: Department of Neuro- and Sensory Physiology, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen Medical Center, Humboldtallee 23, 37073, Göttingen, Germany.
authors.forename: Maria Angela Gomes
authors.initials: MA
authors.lastname: de Castro
authors.affiliation: Department of Neuro- and Sensory Physiology, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen Medical Center, Humboldtallee 23, 37073, Göttingen, Germany.
authors.forename: Burkhard
authors.initials: B
authors.lastname: Rammner
authors.affiliation: Department of Neuro- and Sensory Physiology, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen Medical Center, Humboldtallee 23, 37073, Göttingen, Germany. f.opazo@gwdg.de.
authors.forename: Felipe
authors.initials: F
authors.lastname: Opazo
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism; D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000378:metabolism; D002460:Cell Line; D005456:Fluorescent Dyes; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D018613:Microscopy, Confocal / Q000379:methods*; D013194:Staining and Labeling; D014168:Transferrin / Q000276:immunology / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D052157:Aptamers, Nucleotide; D005456:Fluorescent Dyes; D014168:Transferrin
keywords: Affinity probes; Antibodies; Aptamers; Microscopy; STED; Staining; Super-resolution