title: Subdiffraction fluorescence imaging of biomolecular structure and distributions with quantum dots.
abstract: We introduce semiconductor quantum dot-based fluorescence imaging with approximately 2-fold increased optical resolution in three dimensions as a method that allows both studying cellular structures and spatial organization of biomolecules in membranes and subcellular organelles. Target biomolecules are labelled with quantum dots via immunocytochemistry. The resolution enhancement is achieved by three-photon absorption of quantum dots and subsequent fluorescence emission from a higher-order excitonic state. Different from conventional multiphoton microscopy, this approach can be realized on any confocal microscope without the need for pulsed excitation light. We demonstrate quantum dot triexciton imaging (QDTI) of the microtubule network of U373 cells, 3D imaging of TNF receptor 2 on the plasma membrane of HeLa cells, and multicolor 3D imaging of mitochondrial cytochrome c oxidase and actin in COS-7 cells.
authors.affiliation: Physics Department, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany.
authors.forename: Meike
authors.initials: M
authors.lastname: Heidbreder
authors.forename: Ulrike
authors.initials: U
authors.lastname: Endesfelder
authors.forename: Sebastian
authors.initials: S
authors.lastname: van de Linde
authors.forename: Simon
authors.initials: S
authors.lastname: Hennig
authors.forename: Darius
authors.initials: D
authors.lastname: Widera
authors.forename: Barbara
authors.initials: B
authors.lastname: Kaltschmidt
authors.forename: Christian
authors.initials: C
authors.lastname: Kaltschmidt
authors.forename: Mike
authors.initials: M
authors.lastname: Heilemann
mesh_terms: D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000378:metabolism*; D005453:Fluorescence; D006367:HeLa Cells; D006801:Humans; D007150:Immunohistochemistry; D018613:Microscopy, Confocal / Q000379:methods; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000378:metabolism; D015388:Organelles / Q000378:metabolism; D045663:Quantum Dots; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000199:Actins; D024101:Mitochondrial Proteins; D047889:Receptors, Tumor Necrosis Factor, Type II; D003576:Electron Transport Complex IV