New Cy5 photosensitizers for cancer phototherapy: a low singlet–triplet gap provides high quantum yield of singlet oxygen

Abstract

Highly efficient triplet photosensitizers (PSs) have attracted increasing attention in cancer photodynamic therapy where photo-induced reactive oxygen (ROS, such as singlet oxygen) produces via singlet-triplet intersystem crossing (ISC) of the...

Highly selective generation of singlet oxygen from dioxygen with atomically dispersed catalysts

“…[17][18][19][20][21][22] Conventional approaches to 1 O 2 production mainly include thermal processes using enzymatic or chemical reactions and photosensitization of O 2 with rationally designed photosensitizers. [23][24][25][26] However, the production of 1 O 2 through these approaches is always accompanied by other ROS generation. In addition, thermal processes oen require harsh conditions such as rigorous pH and particular solvents.…”

Attachment of −tBu groups to aza-BODIPY core at 3,5-sites with ultra-large Stokes shift to enhance photothermal therapy through apoptosis mechanism

“…Their singlet oxygen yields are low and calculated to be 8.1% for SMe-tBuazaBDP and 4.4% for CF 3 -tBuazaBDP , respectively [ 58 ]. In terms of the calculation formula, one can find that ISC ( k ISC ) rate is closely related to singlet-triplet energy differences (Δ E st ) [ [59] , [60] , [61] ]. So, to estimate the difficulty of the ISC, the first ten lowest-lying singlet and triplet transitions of SMe-tBuazaBDP have been calculated, as listed in Table S4 .…”

“…So, to estimate the difficulty of the ISC, the first ten lowest-lying singlet and triplet transitions of SMe-tBuazaBDP have been calculated, as listed in Table S4 . Obviously, the energy gap Δ E st between S 1 and T 1 state is about 1 ​eV, which is not a favorable energy difference for ISC [ [59] , [60] , [61] ]. In short, SMe-tBuazaBDP exhibits a weak ISC effect.…”

ER-Targeting Cyanine Dye as an NIR Photoinducer to Efficiently Trigger Photoimmunogenic Cancer Cell Death

“…TCy5, originally proposed as a classic imaging chromophore, is favorable among existing dyes because it combines good water solubility, strong NIR absorption (>650 nm), and a versatile chemical structure. 48 The NIR character allows TCy5 to harvest light energy in deep tissue and image with low tissue scattering in vivo. The meso-position of TCy5 has been herein modified with polyfluorophenyl, which serves two functions: as a ligand for specific ER targeting and as a powerful electron-withdrawing group (EWG) that can enhance the ROS generation ability.…”

“…Herein, thio-pentamethine cyanine (TCy5) dyes have been developed as type II ICD photoinducers. TCy5, originally proposed as a classic imaging chromophore, is favorable among existing dyes because it combines good water solubility, strong NIR absorption (>650 nm), and a versatile chemical structure . The NIR character allows TCy5 to harvest light energy in deep tissue and image with low tissue scattering in vivo .…”