Self‐Assembly Induced Photosensitization of Long‐Tailed Heavy‐Atom‐Free BODIPY Derivatives for Photodynamic Therapy

Abstract

Type I photosensitizers (PSs) are a promising approach for photodynamic therapy (PDT) since they can generate radicals that are tolerant to hypoxia. Thus, the development of highly efficient type I PSs is essential. Self‐assembly is a promising strategy for developing novel PSs with desirable properties. Here, a simple and effective approach is developed to create heavy‐atom‐free PSs for PDT by self‐assembling long‐tailed boron dipyrromethene dyes (BODIPYs). The resulting aggregates BY‐I16 and BY‐I18 can efficiently convert their excited energy to the triplet state, producing reactive oxygen species that are essential for PDT. Furthermore, the aggregation and PDT performance can be regulated by adjusting the length of the tailed alkyl chains. As proof of concept, the efficacy of these heavy‐atom‐free PSs both in vitro and in vivo under both normoxic and hypoxic conditions is demonstrated.

NIR-II Light-Driven Genetically Engineered Exosome Nanocatalysts for Efficient Phototherapy against Glioblastoma

“…This heightened cytotoxicity can be attributed to Mn@Bi 2 Se 3 @RGE-Exos’ ability to generate elevated levels of ROS through multienzyme catalysis under NIR-II irradiation. To corroborate this hypothesis, the ROS production characteristics of Mn@Bi 2 Se 3 @RGE-Exos were evaluated using specialized fluorescent probes, dihydroethidium (DHE) and 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA), − under NIR-II irradiation. As anticipated, a dose-dependent ROS generation was seen in Mn@Bi 2 Se 3 @RGE-Exos-treated C6 cells upon NIR-II irradiation (1064 nm, 1.0 W/cm 2 , 5 min), confirming the intracellular ROS generation by Mn@Bi 2 Se 3 @RGE-Exos (Figure S25).…”

NIR-Absorbing Tetraphenylethene-Containing bisBODIPY Nanoplatforms Demonstrate Effective Lysosome-Targeting and Combinational Phototherapy

“…Inside the NPs, the bisBODIPYs were tightly packed, enhancing the intermolecular exciton coupling of the dimers. This combined intramolecular and intermolecular exciton coupling could help enhance the probability of intersystem crossing, which is crucial for efficient PDT. − Subsequently, the ROS production capacities of the NPs were evaluated. As shown in the Figures f,g and S16–S19, under the same molecular concentration (20 μM) and irradiation condition (755 nm, 0.10 W cm –2 ), the bisBODIPY NPs significantly improved the emission of ROS indicator 2′,7′-dichlorodihydrofluorescein (DCFH).…”

“…Known for its exceptional photophysical properties and robust photo/chemical stability, boron dipyrromethene (BODIPY) is a favored choice in designing phototherapeutic agents. − Extending the π-conjugation of the BODIPY core or constructing oligomers can yield BODIPY derivatives with NIR absorption. − However, most BODIPYs used in tumor phototherapy exhibit a single phototherapeutic effect, either photothermal or photodynamic. − In this study, to address the aforementioned issues, we designed and synthesized two α–α-linked bisBODIPYs with tetraphenylethene (TPE) moieties. The intramolecular J-type exciton coupling of the bisBODIPY not only redshifts the molecular absorption but also enhances the intersystem transition process, thereby enhancing PDT process. − Furthermore, installation of one or two bulky TPE moieties (Figure ) at the α-position of bisBODIPY further extends NIR absorption and confers aggregation-induced emission (AIE) activities, preventing ROS quenching upon aqueous aggregation. − Additionally, the combination of electron-rich TPE as the electron donor and electron-deficient BODIPY core as the electron acceptor creates a donor–acceptor (D–A) structure, likely enhancing spin–orbit coupling and reducing the energy gap between S 1 and T 1 states, thereby promoting intersystem crossing . The rotor characteristics of TPE also improve the efficiency of photothermal conversion .…”

Remote Control of Energy Transformation‐Based Cancer Imaging and Therapy

“…PDT and PTT transform photonic energy into chemical or thermal energy to eliminate tumors, and single photonic energy transformation has been extensively reported for cancer treatment. [ 116–119 ] Due to the oxygen consumption of tumor tissue during PDT, the efficacy of PDT gradually decreases, making it suitable for early cancer treatment. However, the thermal effect of PTT will show better efficacy with prolonged treatment time.…”