title: Detecting and Quantifying Biomolecular Interactions of a Dendritic Polyglycerol Sulfate Nanoparticle Using Fluorescence Lifetime Measurements.
abstract: Interactions of nanoparticles with biomaterials determine the biological activity that is key for the physiological response. Dendritic polyglycerol sulfates (dPGS) were found recently to act as an inhibitor of inflammation by blocking selectins. Systemic application of dPGS would present this nanoparticle to various biological molecules that rapidly adsorb to the nanoparticle surface or lead to adsorption of the nanoparticle to cellular structures such as lipid membranes. In the past, fluorescence lifetime measurements of fluorescently tagged nanoparticles at a molecular and cellular/tissue level have been proven to reveal valuable information on the local nanoparticle environment via characteristic fluorescent lifetime signatures of the nanoparticle bound dye. Here, we established fluorescence lifetime measurements as a tool to determine the binding affinity to fluorescently tagged dPGS (dPGS-ICC; ICC: indocarbocyanine). The binding to a cell adhesion molecule (L-selectin) and a human complement protein (C1q) to dPGS-ICC was evaluated by the concentration dependent change in the unique fluorescence lifetime signature of dPGS-ICC. The apparent binding affinity was found to be in the nanomolar range for both proteins (L-selectin: 87 ± 4 nM and C1q: 42 ± 12 nM). Furthermore, the effect of human serum on the unique fluorescence lifetime signature of dPGS-ICC was measured and found to be different from the interactions with the two proteins and lipid membranes. A comparison between the unique lifetime signatures of dPGS-ICC in different biological environments shows that fluorescence lifetime measurements of unique dPGS-ICC fluorescence lifetime signatures are a versatile tool to probe the microenvironment of dPGS in cells and tissue.
authors.affiliation: Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany. alexander.boreham@fu-berlin.de.
authors.forename: Alexander
authors.initials: A
authors.lastname: Boreham
authors.affiliation: Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany. jpikkemaat@zedat.fu-berlin.de.
authors.forename: Jens
authors.initials: J
authors.lastname: Pikkemaat
authors.affiliation: Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany. pierre.volz@fu-berlin.de.
authors.forename: Pierre
authors.initials: P
authors.lastname: Volz
authors.affiliation: Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany. brodwolf@zedat.fu-berlin.de.|Helmholtz Virtual Institute-Multifunctional Biomaterials for Medicine, Helmholtz-Zentrum Geesthacht, Kantstr. 55, 14513 Teltow, Germany. brodwolf@zedat.fu-berlin.de.
authors.forename: Robert
authors.initials: R
authors.lastname: Brodwolf
authors.affiliation: Institut für Laboratoriumsmedizin, Klinische Chemie und Pathobiochemie, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. christian.Kuehne@charite.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Kuehne
authors.affiliation: Mivenion GmbH, Robert-Koch-Platz 4, 10115 Berlin, Germany. Licha@mivenion.com.
authors.forename: Kai
authors.initials: K
authors.lastname: Licha
authors.affiliation: Helmholtz Virtual Institute-Multifunctional Biomaterials for Medicine, Helmholtz-Zentrum Geesthacht, Kantstr. 55, 14513 Teltow, Germany. haag@chemie.fu-berlin.de.|Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany. haag@chemie.fu-berlin.de.
authors.forename: Rainer
authors.initials: R
authors.lastname: Haag
authors.affiliation: Helmholtz Virtual Institute-Multifunctional Biomaterials for Medicine, Helmholtz-Zentrum Geesthacht, Kantstr. 55, 14513 Teltow, Germany. jens.dernedde@charite.de.|Institut für Laboratoriumsmedizin, Klinische Chemie und Pathobiochemie, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. jens.dernedde@charite.de.
authors.forename: Jens
authors.initials: J
authors.lastname: Dernedde
authors.affiliation: Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany. ulrike.alexiev@fu-berlin.de.|Helmholtz Virtual Institute-Multifunctional Biomaterials for Medicine, Helmholtz-Zentrum Geesthacht, Kantstr. 55, 14513 Teltow, Germany. ulrike.alexiev@fu-berlin.de.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Alexiev
mesh_terms: D050091:Dendrimers / Q000737:chemistry*; D005453:Fluorescence; D005990:Glycerol / Q000737:chemistry; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D013431:Sulfates / Q000737:chemistry*
chemical_list: D050091:Dendrimers; D013431:Sulfates; D005990:Glycerol
keywords: dendritic polymers; fluorescence lifetime; nanomedicine; protein corona