Upconversion NIR-II fluorophores for mitochondria-targeted cancer imaging and photothermal therapy

Abstract

NIR-II fluorophores have shown great promise for biomedical applications with superior in vivo optical properties. To date, few small-molecule NIR-II fluorophores have been discovered with donor-acceptor-donor (D-A-D) or symmetrical structures, and upconversion-mitochondria-targeted NIR-II dyes have not been reported. Herein, we report development of D-A type thiopyrylium-based NIR-II fluorophores with frequency upconversion luminescence (FUCL) at ~580 nm upon excitation at ~850 nm. H4-PEG-PT can not only quickly and effectively image mitochondria in live or fixed osteosarcoma cells with subcellular resolution at 1 nM, but also efficiently convert optical energy into heat, achieving mitochondria-targeted photothermal cancer therapy without ROS effects. H4-PEG-PT has been further evaluated in vivo and exhibited strong tumor uptake, specific NIR-II signals with high spatial and temporal resolution, and remarkable NIR-II image-guided photothermal therapy. This report presents the first D-A type thiopyrylium NIR-II theranostics for synchronous upconversion-mitochondria-targeted cell imaging, in vivo NIR-II osteosarcoma imaging and excellent photothermal efficiency.

All-in-one mitochondria-targeted NIR-II fluorophores for cancer therapy and imaging

“…The E gap (1.7 eV) of H4–PEG-Glu was close to that of CH1055 (1.5 eV) with a typical NIR-II optical E gap based on previous results. 17 H4–PEG-Glu was further purified using HPLC and all compounds were characterized by 1 H-NMR, 13 C-NMR, HRMS and MALDI-TOF-MS (Fig. S1–S6 † ).…”

Recent Progress on NIR-II Photothermal Therapy

“…Zeng et al (2018b) conjugated water-soluble and biocompatible smallmolecule NIR-II dye H2a-4T with fetal bovine serum (FBS) and Cetuximab proteins to enhance the tumor targeting and achieved good PTT effect on colorectal cancer. Assorted dyes with NIR-II fluorescence were adopted and developed for use in PTT with good photothermal effect, and showed promising perspective of NIR-II dyes utilized for imaging-guided PTT Zhou et al, 2020a;Xu et al, 2020b;Chen et al, 2020;Sun et al, 2020).…”

NaYS2:Er3+ - a highly efficient NIR II response multi-photon up-conversion phosphor

“…Recently, the near-infrared second (NIR II) spectral region, especially for 1530 nm, shows great potential in the large penetration depth for tissue, and high-resolution imaging etc [24][25][26][27] . Particularly, 1530 nm is also the wavelength of optical communication, exhibits a low loss in transmission, and is widely used in metro, long-distance, ultra-long-distance and submarine optical cable systems [28][29][30][31] .…”