A pH-sensitive supermolecular fluorescent probe for albumin-mediated cell imaging

Abstract

A supermolecular fluorescent probe with favorable pH-sensitive serum albumin responsiveness was successfully fabricated based on the assembly of a binary host-guest complex of water-soluble pillar [5]arene (WP5) and ICT probe DPI. DPI possessed a favorable fluorescence "turn-on" property towards bovine serum albumin (BSA). This property was retained after the binary amphipathic complex formation between WP5 and DPI. Moreover, due to the excellent pH responsiveness of WP5, WP5⊃DPI complex exhibited favorable pH-sensitive BSA responsiveness. The WP5⊃DPI complex also possessed strong BSA binding ability. Common commercial drugs had a negligible adverse effect on the BSA responsiveness of WP5⊃DPI complex. Furthermore, the amphiphilic WP5⊃DPI complex assembled into stable spherical nanoparticles in solution. Such a pH-sensitive supramolecular fluorescent probe had negligible cytotoxicity but exhibited excellent cell permeability and favorable cell imaging properties, demonstrating potential for albumin-mediated precise tumor imaging.