title: Binding of human serum albumin to PEGylated liposomes: insights into binding numbers and dynamics by fluorescence correlation spectroscopy.
abstract: Liposomes for medical applications are often administered by intravenous injection. Once in the bloodstream, the liposomes are covered with a "protein corona", which impacts the behavior and eventual fate of the liposomes. Currently, many aspects of the liposomal protein corona are not well understood. For example, there is generally a lack of knowledge about the liposome binding affinities and dynamics of common types of blood plasma proteins. Fluorescence correlation spectroscopy (FCS) is a powerful experimental technique that potentially can provide such knowledge. In this study, we have used FCS to investigate the binding of human serum albumin (HSA) to standard types of PEGylated fluid-phase liposomes (consisting of DOPC and DOPE-PEG2k) and PEGylated gel-phase liposomes (consisting of DSPC and DSPE-PEG2k) with various PEG chain surface densities. We detected no significant binding of HSA to the PEGylated fluid-phase liposomes. In contrast, we found that HSA bound tightly to the PEGylated gel-phase liposomes, although only a low number of HSA molecules could be accommodated per liposome. Overall, we believe that our data provides a useful benchmark for other researchers interested in studying the liposomal protein corona.
authors.affiliation: Department of Micro- and Nanotechnology, DTU Nanotech, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. tlan@nanotech.dtu.dk and Center for Nanomedicine and Theranostics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
authors.forename: Kasper
authors.initials: K
authors.lastname: Kristensen
authors.affiliation: Department of Micro- and Nanotechnology, DTU Nanotech, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. tlan@nanotech.dtu.dk and Center for Nanomedicine and Theranostics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Urquhart
authors.affiliation: Department of Chemistry, DTU Chemistry, Technical University of Denmark, 2800 Kongens Lyngby, Denmark and Center for Nanomedicine and Theranostics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
authors.forename: Esben
authors.initials: E
authors.lastname: Thormann
authors.affiliation: Department of Micro- and Nanotechnology, DTU Nanotech, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. tlan@nanotech.dtu.dk and Center for Nanomedicine and Theranostics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Andresen