Bioimaging of Hyaluronate–Interferon α Conjugates Using a Non-Interfering Zwitterionic Fluorophore

Abstract

We conducted real-time bioimaging of the hyaluronate–interferon α (HA–IFNα) conjugate using a biologically inert zwitterionic fluorophore of ZW800-1 for the treatment of hepatitis C virus (HCV) infection. ZW800-1 was labeled on the IFNα molecule of the HA–IFNα conjugate to investigate its biodistribution and clearance without altering its physicochemical and targeting characteristics. Confocal microscopy clearly visualized the effective <i>in vitro</i> cellular uptake of the HA–IFNα conjugate to HepG2 cells. After verifying the biological activity in Daudi cells, we conducted the pharmacokinetic analysis of the HA–IFNα conjugate, which confirmed its target-specific delivery to the liver with a prolonged residence time longer than that of PEGylated IFNα. <i>In vivo</i> and <i>ex vivo</i> bioimaging of the ZW800-1-labeled HA–IFNα conjugate directly showed real-time biodistribution and clearance of the conjugate that are consistent with the biological behaviors analyzed by an enzyme-linked immunosorbent assay. Furthermore, the elevated level of OAS1 mRNA in the liver confirmed <i>in vivo</i> antiviral activity of HA–IFNα conjugates. With the data taken together, we could confirm the feasibility of ZW800-1 as a biologically inert fluorophore and target-specific HA–IFNα conjugate for the treatment of HCV infection