Hyperbranched Phosphorescent Conjugated Polymer Dots with Iridium(III) Complex as the Core for Hypoxia Imaging and Photodynamic Therapy

Abstract

Real-time monitoring of the contents of molecular oxygen (O) in tumor cells is of great significance in early diagnosis of cancer. At the same time, the photodynamic therapy (PDT) could be realized by highly toxic singlet oxygen (O) generated in situ during the O sensing, making it one of the most promising methods for cancer therapy. Herein, the iridium(III) complex cored hyperbranched phosphorescent conjugated polymer dots with the negative charges for hypoxia imaging and highly efficient PDT was rationally designed and synthesized. The incomplete energy transfer between the polyfluorene and the iridium(III) complexes realized the ratiometric sensing of O for the accurate measurements. Furthermore, the O-dependent emission lifetimes are also used in photoluminescence lifetime imaging and time-gated luminescence imaging for eliminating the autofluorescence remarkably to enhance the signal-to-noise ratio of imaging. Notably, the polymer dots designed could generate the O effectively in aqueous solution, and the image-guided PDT of the cancer cells was successfully realized and investigated in detail by confocal laser scanning microscope. To the best of our knowledge, this represents the first example of the iridium(III) complex cored hyperbranched conjugated polymer dots with the negative charges for both hypoxia imaging and PDT of cancer cells simultaneously.

<p>Multifunctional hypoxia imaging nanoparticles: multifunctional tumor imaging and related guided tumor therapy</p>

“…Feng et al prepared Ir(III) complex hyperbranched phosphorescent-conjugated Pdots for hypoxia imaging and PDT. 52 The scholars chose phosphorescent oxygen sensor fac-tris(1-phenylisoquinolinato-N,C2′)iridium(III) and the oxygen-insensitive dye 9,9-dioctylfluorene to synthesize hyperbranched conjugated polymer (Ir-HPC). The surface was coated with poly(styreneco-maleic anhydride) (PSMA) to fabricate Ir-HPC/PSMA dots.…”

High‐Performance Organic Electroluminescence: Design from Organic Light‐Emitting Materials to Devices

“…Conjugated polymers with iridium(III) complex in linear chain often result in the self‐quenching of the phosphorescence due to the strong interchain interactions, as illustrated in Figure . To solve this problem, the iridium(III) complex cored hyperbranched conjugated polymers emerge, because they possess compact three‐dimensional branched chains, the iridium(III) complex is completely shielded by the branched structures, suppressing the phosphorescence self‐quenching, thereby enhancing solid‐state emission effectively …”

Recent Progress on the Exploration of the Biological Utility of Cyclometalated Iridium(III) Complexes

“…Zhao, Wang, and coworkers continued to develop dual emissive probes for O 2 , employing poly(fluorene) as a fluorophore . The group recently reported the preparation and applications of polymer dots consisting of a charge‐neutral, hyperbranched Ir(III) complex and poly(styrene‐ co ‐maleic anhydride) (PSMA) ( 34 in Scheme ) . In this system, PSMA was to impart negative charges to the polymer dots for improved hydrophilicity and for minimization of the aggregation of polymer dots.…”