Photodynamic therapy (PDT) strategy has been widely used in tumor treatment, and the reagents for reactive oxygen species (ROS) play a crucial role. Herein, we develop a fluorogen (TTB) containing an electron-accepting benzo[1,2-b:4,5-b′]dithiophene 1,1,5,5-tetraoxide core and electron-donating 4,4′-(2,2-diphenylethene-1,1-diyl)bis(N,N-diphenylaniline) groups for image-guided targeting PDT application. TTB exhibits a prominent aggregation-induced emission (AIE) property with strong near-infrared (NIR) fluorescence in aggregates and is capable of efficiently generating ROS of O2•– and 1O2 under white light irradiation. The nanoparticles (RGD-4R-MPD/TTB NPs) with NIR emission (∼730 nm), high photostability, and low dark cytotoxicity are fabricated by encapsulating TTB within polymeric matrix and then modified with RGD-4R peptide. They show excellent performance in targeting PDT treatment of PC3, HeLa, and SKOV-3 cancer cells in vitro. The investigations on pharmacokinetics, biodistribution, and long-term tracing in vivo reveal that RGD-4R-MPD/TTB NPs can selectively accumulate in tumors for real-time, long-term image-guided PDT treatment. The RGD-4R-MPD/TTB NPs-mediated PDT in multiple xenograft tumor models disclose that the growth of cervical, prostate, and ovarian cancers in mice can be effectively inhibited. These results demonstrate that the reagents employing NIR fluorogen TTB as a photosensitizer could be promising candidates for in vivo image-guided PDT treatments of tumors.
Achieving near-zero thermal expansion (NZTE) in single-phase materials over broad temperature ranges is crucial yet challenging for precision applications. Here, we report a new family of NZTE materials based on triple tetragonal-tungsten-bronze (TTB) oxides, including Ta 8 W 9 O 47 (TWO), (Nb 0.5 Ta 0.5 ) 8 W 9 O 47 (NTWO), and (Nb 0.5 Ta 0.5 ) 8 (Mo 0.5 W 0.5 ) 9 O 47 (NTMWO), synthesized via solid-state reaction and entropy-driven cation doping. High-temperature X-ray diffraction reveals anisotropic lattice behavior in all compositions: positive expansion along the a - and b -axes counterbalanced by negative expansion along the c -axis. This compensation yields average linear coefficients of thermal expansion (CTE) near zero ( α l < 1.30 µK −1 ) from 300 to 1673 K. Notably, Nb-doping in NTWO optimizes this balance, achieving the lowest α l of 0.656(43) µK −1 . Distinct temperature regimes highlight specific advantages: TWO maintains stable NZTE ( α dil = −0.455(1) µK −1 ) from 173–773 K; NTWO exhibits ultralow CTE (−0.079(1) µK −1 ) between 473–773 K; and NTMWO demonstrates exceptional dimensional stability at cryogenic temperatures (93–300 K, α dil = −0.096(1) µK −1 ). The bulk NZTE behavior stems from the synergy between the intrinsic anisotropic lattice expansion and microstructural features, such as rod-like grains and porosity. These results establish Ta 8 W 9 O 47 -type TTB oxides as a robust, non-ferroelectric platform for designing single-phase NZTE ceramics for precision and aerospace applications.
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