Boron-dipyrromethene (BODIPY) dyes have aroused considerable interest in cancer theranostics over the past decade because of robust photochemical properties. Although a large number of BODIPY photosensitizers (PSs) containing heavy atoms have been reported, the development of heavy-atom-free BODIPY PSs for oncologic photodynamic therapy (PDT) has been limited mainly by the uncertainty in intersystem crossing (ISC) mechanisms, unbalanced phototoxic effectiveness and fluorescence quantum yields, and aggregation-caused quenching effects. In addition, the lack of extensive in vivo studies of heavy-atom-free BODIPY PSs continues to limit clinical application. Herein, novel heavy-atom-free BODIPY-phenoxazine triads (BDP-8/BDP-9) that generate efficient excited triplet states via radical pair intersystem crossing (RP-ISC) followed by triplet charge recombination were developed for use in fluorescence image-guided PDT. BDP-8/BDP-9 exhibited high molar absorption coefficients, prominent aggregation-induced emission, and excellent singlet oxygen generation capability upon light irradiation. The corresponding BODIPY nanoparticles (BDP-8/BDP-9 NPs) with bright red emission, considerable phototoxicity, and excellent tumor-targeting ability were simply prepared by encapsulating BDP-8/BDP-9 PSs in a polymeric matrix. More importantly, the results of both in vitro and in vivo experiments demonstrated the considerable potential of BDP-8 NPs for image-guided photodynamic cancer therapy. This study may inspire the development of potential BODIPY-based nanoagents for cancer theranostics.
Bibliographical noteFunding Information:
This study was supported by grants from the National Research Foundation of Korea (NRF) funded by the Korean government (MSIP) (No. 2012R1A3A2048814 for J.Y. and No. 2019R1A6A1A11044070 for S.P.). The high-resolution mass spectrometry analysis was performed using a Synapt G2-HDMS mass spectrometer (Waters, Manchester, U.K.) operating on MassLynx 4.1 software at KBSI (Korea Basic Science Institute, Ochang, Center of Research Equipment).
© 2021 American Chemical Society.
ASJC Scopus subject areas
- General Chemistry
- General Chemical Engineering
- Materials Chemistry