Spectroscopic characterization of the binding mechanism of fluorescein and carboxyfluorescein in human serum albumin

Saba A J Sulaiman, H. Udani Kulathunga, Osama K. Abou-Zied

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Fluorescein (FL) and some of its precursors have proven to be effective fluorescent tracers in pharmaceutical and medical applications owing to their high quantum yield of fluorescence in physiological conditions and their high membrane permeability. In order to protect FL from metabolic effects during the process of its delivery, human serum albumin (HSA) has been used as a carrier because of its compatibility with the human body. In the present work, we used spectroscopic methods to characterize the binding mechanisms of FL and one of its derivatives, 5(6)- carboxyfluorescein (CFL), in the HSA protein. The absorbance change of the two ligands (FL and CFL) was quantified as a function of the HSA concentration and the results indicate a moderate binding strength for the two ligands inside HSA (1.00 ± 0.12 × 104 M-1). The quenching effect of FL(CFL) on the fluorescence intensity of W214 (the sole tryptophan in HSA) indicates that FL and CFL occupy Site I in the protein which is known to bind several hydrophobic drugs. By performing site-competitive experiments, the location of the ligands is determined to be similar to that of the anticoagulant drug warfarin. At higher ratios of [ligand]/[HSA], we observed an upward curvature in the Stern-Volmer plots which indicates that the ligands occupy more pockets in Site I, close to W214. Our results indicate that both ligands bind in HSA with a moderate strength that should not affect their release when used as fluorescent reporters. The chemical and physical identities of the two ligands are also preserved inside the HSA binding sites.

Original languageEnglish
Title of host publicationProgress in Biomedical Optics and Imaging - Proceedings of SPIE
PublisherSPIE
Volume9339
ISBN (Print)9781628414295
DOIs
Publication statusPublished - 2015
EventReporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications VII - San Francisco, United States
Duration: Feb 8 2015Feb 10 2015

Other

OtherReporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications VII
CountryUnited States
CitySan Francisco
Period2/8/152/10/15

Fingerprint

Fluorescein
albumins
Serum Albumin
serums
Ligands
ligands
Fluorescence
drugs
Proteins
anticoagulants
proteins
fluorescence
Medical applications
Quantum yield
Binding sites
6-carboxyfluorescein
tryptophan
human body
Drug products
Warfarin

Keywords

  • Carboxyfluorescein
  • Drug binding sites
  • Fluorescein
  • Fluorescent probes
  • Fluorescent tracers in medicine
  • Human serum albumin

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

Cite this

Sulaiman, S. A. J., Kulathunga, H. U., & Abou-Zied, O. K. (2015). Spectroscopic characterization of the binding mechanism of fluorescein and carboxyfluorescein in human serum albumin. In Progress in Biomedical Optics and Imaging - Proceedings of SPIE (Vol. 9339). [933908] SPIE. https://doi.org/10.1117/12.2077520

Spectroscopic characterization of the binding mechanism of fluorescein and carboxyfluorescein in human serum albumin. / Sulaiman, Saba A J; Kulathunga, H. Udani; Abou-Zied, Osama K.

Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Vol. 9339 SPIE, 2015. 933908.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Sulaiman, SAJ, Kulathunga, HU & Abou-Zied, OK 2015, Spectroscopic characterization of the binding mechanism of fluorescein and carboxyfluorescein in human serum albumin. in Progress in Biomedical Optics and Imaging - Proceedings of SPIE. vol. 9339, 933908, SPIE, Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications VII, San Francisco, United States, 2/8/15. https://doi.org/10.1117/12.2077520
Sulaiman SAJ, Kulathunga HU, Abou-Zied OK. Spectroscopic characterization of the binding mechanism of fluorescein and carboxyfluorescein in human serum albumin. In Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Vol. 9339. SPIE. 2015. 933908 https://doi.org/10.1117/12.2077520
Sulaiman, Saba A J ; Kulathunga, H. Udani ; Abou-Zied, Osama K. / Spectroscopic characterization of the binding mechanism of fluorescein and carboxyfluorescein in human serum albumin. Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Vol. 9339 SPIE, 2015.
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