title: Enhanced fluorescence imaging of live cells by effective cytosolic delivery of probes.
abstract: BACKGROUND
  Microscopic techniques enable real-space imaging of complex biological events and processes. They have become an essential tool to confirm and complement hypotheses made by biomedical scientists and also allow the re-examination of existing models, hence influencing future investigations. Particularly imaging live cells is crucial for an improved understanding of dynamic biological processes, however hitherto live cell imaging has been limited by the necessity to introduce probes within a cell without altering its physiological and structural integrity. We demonstrate herein that this hurdle can be overcome by effective cytosolic delivery.
  
  
  RESULTS
  We show the delivery within several types of mammalian cells using nanometre-sized biomimetic polymer vesicles (a.k.a. polymersomes) that offer both highly efficient cellular uptake and endolysomal escape capability without any effect on the cellular metabolic activity. Such biocompatible polymersomes can encapsulate various types of probes including cell membrane probes and nucleic acid probes as well as labelled nucleic acids, antibodies and quantum dots.
  
  
  CONCLUSIONS
  We show the delivery of sufficient quantities of probes to the cytosol, allowing sustained functional imaging of live cells over time periods of days to weeks. Finally the combination of such effective staining with three-dimensional imaging by confocal laser scanning microscopy allows cell imaging in complex three-dimensional environments under both mono-culture and co-culture conditions. Thus cell migration and proliferation can be studied in models that are much closer to the in vivo situation.
authors.affiliation: Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom.
authors.forename: Marzia
authors.initials: M
authors.lastname: Massignani
authors.forename: Irene
authors.initials: I
authors.lastname: Canton
authors.forename: Tao
authors.initials: T
authors.lastname: Sun
authors.forename: Vanessa
authors.initials: V
authors.lastname: Hearnden
authors.forename: Sheila
authors.initials: S
authors.lastname: Macneil
authors.forename: Adam
authors.initials: A
authors.lastname: Blanazs
authors.forename: Steven P
authors.initials: SP
authors.lastname: Armes
authors.forename: Andrew
authors.initials: A
authors.lastname: Lewis
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Battaglia
mesh_terms: D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism*; D005337:Fibrin / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D005453:Fluorescence; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D057054:Molecular Imaging / Q000379:methods*; D015335:Molecular Probes / Q000737:chemistry / Q000378:metabolism*; D011108:Polymers / Q000378:metabolism; D012235:Rhodamines / Q000378:metabolism; D013194:Staining and Labeling
chemical_list: D015335:Molecular Probes; D011108:Polymers; D012235:Rhodamines; D005337:Fibrin
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