title: Near-infrared quantum dots for HER2 localization and imaging of cancer cells.
abstract: BACKGROUND
  Quantum dots are fluorescent nanoparticles with unique photophysical properties that allow them to be used as diagnostic, therapeutic, and theranostic agents, particularly in medical and surgical oncology. Near-infrared-emitting quantum dots can be visualized in deep tissues because the biological window is transparent to these wavelengths. Their small sizes and free surface reactive groups that can be conjugated to biomolecules make them ideal probes for in vivo cancer localization, targeted chemotherapy, and image-guided cancer surgery. The human epidermal growth factor receptor 2 gene (HER2/neu) is overexpressed in 25%-30% of breast cancers. The current methods of detection for HER2 status, including immunohistochemistry and fluorescence in situ hybridization, are used ex vivo and cannot be used in vivo. In this paper, we demonstrate the application of near-infrared-emitting quantum dots for HER2 localization in fixed and live cancer cells as a first step prior to their in vivo application.
  
  
  METHODS
  Near-infrared-emitting quantum dots were characterized and their in vitro toxicity was established using three cancer cell lines, ie, HepG2, SK-BR-3 (HER2-overexpressing), and MCF7 (HER2-underexpressing). Mouse antihuman anti-HER2 monoclonal antibody was conjugated to the near-infrared-emitting quantum dots.
  
  
  RESULTS
  In vitro toxicity studies showed biocompatibility of SK-BR-3 and MCF7 cell lines with near-infrared-emitting quantum dots at a concentration of 60 μg/mL after one hour and 24 hours of exposure. Near-infrared-emitting quantum dot antiHER2-antibody bioconjugates successfully localized HER2 receptors on SK-BR-3 cells.
  
  
  CONCLUSIONS
  Near-infrared-emitting quantum dot bioconjugates can be used for rapid localization of HER2 receptors and can potentially be used for targeted therapy as well as image-guided surgery.
authors.affiliation: UCL Centre for Nanotechnology and Regenerative Medicine, University College London, London, UK.
authors.forename: Sarwat B
authors.initials: SB
authors.lastname: Rizvi
authors.affiliation: UCL Centre for Nanotechnology and Regenerative Medicine, University College London, London, UK.
authors.forename: Sepideh
authors.initials: S
authors.lastname: Rouhi
authors.affiliation: Department of Physics, King's College London, London, UK.
authors.forename: Shohei
authors.initials: S
authors.lastname: Taniguchi
authors.affiliation: UCL Centre for Nanotechnology and Regenerative Medicine, University College London, London, UK.
authors.forename: Shi Yu
authors.initials: SY
authors.lastname: Yang
authors.affiliation: Department of Physics, King's College London, London, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Green
authors.affiliation: UCL Centre for Nanotechnology and Regenerative Medicine, University College London, London, UK ; Royal Free London NHS Foundation Trust Hospital, London, UK.
authors.forename: Mo
authors.initials: M
authors.lastname: Keshtgar
authors.affiliation: UCL Centre for Nanotechnology and Regenerative Medicine, University College London, London, UK ; Royal Free London NHS Foundation Trust Hospital, London, UK.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Seifalian
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000175:diagnosis / Q000378:metabolism; D045744:Cell Line, Tumor; D005260:Female; D056945:Hep G2 Cells; D006801:Humans; D061986:MCF-7 Cells; D051379:Mice; D050997:Nanomedicine; D036103:Nanotechnology; D009369:Neoplasms / Q000175:diagnosis* / Q000378:metabolism*; D045663:Quantum Dots / Q000737:chemistry / Q000648:ultrastructure; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology / Q000378:metabolism*; D019265:Spectroscopy, Near-Infrared
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
keywords: HER2 localization; anti-HER2 antibody; cancer; in vitro imaging; nanotechnology; quantum dots