title: Hydrodynamic Radii of Ranibizumab, Aflibercept and Bevacizumab Measured by Time-Resolved Phosphorescence Anisotropy.
abstract: To measure the hydrodynamic radii of intravitreal anti-VEGF drugs ranibizumab, aflibercept and bevacizumab with μs time-resolved phosphorescence anisotropy.
  
  
  
  Ruthenium-based dye Ru(bpy)2(mcbpy - O - Su - ester)(PF6)2, whose lifetime of several hundred nanoseconds is comparable to the rotational correlation time of these drugs in buffer, was used as a label. The hydrodynamic radii were calculated from the rotational correlation times of the Ru(bpy)2(mcbpy - O - Su - ester)(PF6)2-labelled drugs obtained with time-resolved phosphorescence anisotropy measurements in buffer/glycerol solutions of varying viscosity.
  
  
  
  The measured radii of 2.76±0.04 nm for ranibizumab, 3.70±0.03 nm for aflibercept and 4.58±0.01 nm for bevacizumab agree with calculations based on molecular weight and other experimental measurements.
  
  
  
  Time-resolved phosphorescence anisotropy is a relatively simple and straightforward method that allows experimental measurement of the hydrodynamic radius of individual proteins, and is superior to theoretical calculations which cannot give the required accuracy for a particular protein.
authors.affiliation: Department of Physics, King's College London, Strand, London, WC2R 2LS, UK.
authors.forename: Liisa M
authors.initials: LM
authors.lastname: Hirvonen
authors.affiliation: Department of Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, Lambeth Wing, London, SE1 7EH, UK.
authors.forename: Gilbert O
authors.initials: GO
authors.lastname: Fruhwirth
authors.affiliation: School of Medicine, King's College London, London, SE5 9RS, UK.|Department of Ophthalmology, King's College Hospital, London, SE5 9RS, UK.
authors.forename: Nishanthan
authors.initials: N
authors.lastname: Srikantha
authors.affiliation: Department of Physics, King's College London, Strand, London, WC2R 2LS, UK.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Barber
authors.affiliation: Department of Ophthalmology, King's College Hospital, London, SE5 9RS, UK.
authors.forename: James E
authors.initials: JE
authors.lastname: Neffendorf
authors.affiliation: Department of Physics, King's College London, Strand, London, WC2R 2LS, UK. klaus.suhling@kcl.ac.uk.
authors.forename: Klaus
authors.initials: K
authors.lastname: Suhling
authors.affiliation: School of Medicine, King's College London, London, SE5 9RS, UK.|Department of Ophthalmology, King's College Hospital, London, SE5 9RS, UK.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Jackson
mesh_terms: D020533:Angiogenesis Inhibitors / Q000032:analysis / Q000737:chemistry; D000818:Animals; D016880:Anisotropy; D000068258:Bevacizumab / Q000032:analysis / Q000737:chemistry*; D002417:Cattle; D057446:Hydrodynamics; D008163:Luminescent Measurements / Q000379:methods*; D000069579:Ranibizumab / Q000032:analysis / Q000737:chemistry*; D040262:Receptors, Vascular Endothelial Growth Factor / Q000032:analysis / Q000737:chemistry*; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000032:analysis / Q000737:chemistry
chemical_list: D020533:Angiogenesis Inhibitors; D011993:Recombinant Fusion Proteins; C533178:aflibercept; D012710:Serum Albumin, Bovine; D000068258:Bevacizumab; D040262:Receptors, Vascular Endothelial Growth Factor; D000069579:Ranibizumab
keywords: fluorescence; hydrodynamic radius; phosphorescence; rotational diffusion; time-resolved anisotropy