A Warfarin-Based Supramolecular Nanoprobe for Cell Imaging and Drug Delivery

Warfarin is a well-established oral anticoagulant with decades of clinical application. Structurally, it selectively binds to Site 1 on serum albumin and contains a coumarin scaffold that confers intrinsic fluorescent characteristics, enabling potential bioimaging and drug delivery applications. Herein, a warfarin-based supramolecular nanoprobe was successfully fabricated through the self-assembly of a complex composed of water-soluble pillar[5]arene (WP5) and a warfarin-derived guest molecule (WFY). WFY exhibited strong intrinsic fluorescence and demonstrated selective fluorescence responsiveness toward bovine serum albumin (BSA). Interestingly, the complexation of WFY with WP5 did not alter its fluorescent properties. The WP5 ⊃ WFY complex inherently displayed robust intrinsic fluorescence, which was further selectively amplified upon its interaction with BSA. Moreover, the WP5 ⊃ WFY complex, being amphiphilic, self-assembled into spherical supramolecular nanoparticles. These nanoparticles possessed favorable doxorubicin (DOX) loading capacity. The drug-loaded nanoparticles DOX@WP5 ⊃ WFY exhibited physiologically stable yet rapid drug release properties in acidic environments. Additionally, the WP5 ⊃ WFY nanoparticles exhibited negligible cytotoxicity and excellent cell imaging capabilities. After loading with DOX, they enhanced the cytotoxicity of DOX while retaining their good cell imaging properties. The warfarin-based supramolecular nanoprobe holds potential as a promising carrier for theranostic strategies in cancer research and treatment.