Latest ArticlesSonodynamic therapy (SDT) exhibits promising clinical applications in cancer treatment owing to its advantages, including ultrasonic cavitation effect, mechanical effect, and deep tissue penetration. Titanium dioxide (TiO2) nanomaterials, recognized as excellent sonosensitizers, have been extensively studied in cancer SDT. This review first outlines the mechanism of TiO2-based SDT, then systematically discusses the regulation of TiO2 sonosensitivity, covering aspects such as morphology, particle size, element doping, defect engineering, heterojunction structure, and interactions with the tumor microenvironment. Furthermore, the review generalizes ultrasound-responsive TiO2-based therapeutic modalities for tumor treatment, including SDT, SDT combined with chemotherapy, chemodynamic therapy, photothermal therapy, immunotherapy, and treatment visualization. Finally, the review navigates the ongoing challenges and prospects in TiO2-based cancer SDT.
It has been widely recognized that hole transporting materials (HTMs) play a key role in the rapid progress of perovskite solar cells (PVSCs). However, common organic HTMs such as spiro-OMeTAD not only suffer from high synthetic costs, but also usually require the additional chemical doping process to improve their hole transport ability, which unfortunately induces the terrible stability issue. Therefore, it is urgent to develop low-cost dopant-free HTMs for efficient and stable PVSCs. In this work, we have successfully developed a new class of efficient dopant-free fluoranthene-based HTMs (TPF1–5) with quite low lab synthetic costs by combining donor-acceptor and branched structure designs. The detailed structure-property study revealed that tuning the twisted arms at different substitution sites would regulate the intermolecular interactions and film-forming ability, thereby significantly affecting the performance of the HTMs. By applying these HTMs in conventional PVSCs, the dopant-free TPF1-based devices not only achieved the best efficiency of 21.76%, which is comparable to that of the doped spiro-OMeTAD control devices, but also showed much better operational stability, which maintained over 87% of the initial efficiency under maximum power point tracking after 1038 h.
GPCRs are dominant targets for approved drugs and the discovery of lead compound targeting them is still challengeable. Affinity-based screening technique is a promising platform to uncover GPCR ligands. However, the intrinsic activities of them are seldom simultaneously determined during the screening. Taking beta2-adrenoceptor (β2AR) as a probe, this work created a strategy for screening GPCR ligands with simultaneous characterization of their downstream G protein binding responses associated with GTP. The strategy included (ⅰ) the design and expression of a protein miniature formed by β2AR and G protein α-subunit (Gαs) using circularly permuted HaloTag (cpHalo) as a flexible linker; (ⅱ) immobilization of the miniature onto silica gel by a click dehalogenation reaction; (ⅲ) systematic characterization of the immobilized miniature by fluorescent and chromatographic studies, and (ⅳ) simulating of ligand-induced β2AR-Gαs signaling cascade by chromatographic assays using GTP as an indicator. The immobilized miniature exhibited specificity to β2AR and Gαs antibodies and ligands. The specificity is stable at least within fifteen days with the variation less than 1%. The intrinsic activities of β2AR ligands were distinguished by the changes of GTP chromatographic behaviors on Gαs-cpHalo-β2AR column. Agonists strengthened the binding affinity and kinetics of GTP with Gαs, while antagonist did not give any effect on them. With the intrinsic activity evaluation, we believe, it will improve the attributes of chromatographic methods for drug discovery efforts with minimizing false-positive results.
In recent years, multicolor cascade supramolecular assemblies with controllable topological morphology have become a research hotspot due to their wide application in light-emitting materials, cell imaging and other fields. Herein, several kinds of macrocycles including cucurbiturils, calixarene and cyclodextrins are used as building blocks to construct fluorescent assemblies with anthryl-conjugated phenylpyridine (G), wherein cucurbit[8]uril (CB[8]) and G can form nanowires at a stoichiometric ratio of n: n through host-guest encapsulation to form a non-covalent heterodimer. Significantly, the macrocycle confinement effect drastically enhances the fluorescence emission of G and emission peak generated bathochromic shift from 500 nm to 600 nm. When the supramolecular polymer is further assembled with amphiphilic calix[4]arene (SC4A8), the fluorescence emission of G⊂CB[8] further increases to 1.4 times, accompanied by the morphological transformation from linear structure to nanorod structure. Subsequently, a very small amount of dye Cy5 is added to the assembly solution as an energy receptor, and the negatively charged G⊂CB[8]@SC4A8 system is regarded as an energy donor. The efficient energy transfer process enables near-infrared (NIR) emission at 675 nm with 71% energy transfer efficiency (ΦET) at a donor/receptor ratio of 100:1. Finally, the cascade supramolecular assembly has been successfully applied to targeted imaging in the nucleus of HeLa and A549 cancer cells.
Triphenylamine (TPA)-containing 2-(2′-hydroxyphenyl)benzoxazoles (2a-2c) have been synthesized via a highly efficient rhodium-catalyzed C–H/C–H cross-coupling reaction. Compound 2a is a novel mechanofluorochromic material with blue-shifted mechanochromic properties. Compounds 2b and 2c presented opposite mechanochromic trends. For 2b, the enol-form emission enhanced, and the keto-form emission blue-shift after grinding. In contrast, 2c exhibited the weak enol-form emission disappeared and the keto-form emission slightly red-shift after grinding treatments. The estrone-containing 2b-based water-dispersed nanoparticles (NPs) exhibit apparent dual-emission and were applied for fluorescence images. In addition, bis(TPA)-containing 2c-based devices exhibit dual-emission with good performance and a singlet exciton yield of 92%, which breaks through the theoretical upper limit of 25% in conventional fluorescent OLEDs. This is one of the highest exciton utilization values recorded for the ESIPT molecules with a dual emission system.
Reliable and selective sensing of dopamine (DA) is essential for early diagnosis of mental diseases. Among the various potential methods, nanozyme-based sensing systems have demonstrated promising sensitivity and reliability. However, owing to the lack of substrate specificity, it is challenging to selectively detect DA using nanozymes. Herein, based on the reactivity of the DA oxidation intermediates, we report a cascade colorimetric sensing system for the selective detection of DA using only a single nanozyme. It was disclosed that the oxidation product of DA catalyzed by Co-N-doped carbon sheets (Co-N-C, a common oxidase-like nanozyme), dopamine quinone (DAQ), showed significant biocatalytic electron-donating activity in the reduction of O2 to generate O2•−. Further using O2•− to oxidize 3,3′,5,5′-tetramethylbenzidine (TMB), a colorimetric sensing platform for DA was constructed with a linear detection range of 50 nmol/L to 50 µmol/L and a low limit of detection of 4 nmol/L. Thanks to the reactivity of the oxidation product, without any biometric units (such as nucleic acids, enzymes, and antibodies/antigens), the reaction selectivity of DA against other interferences (e.g., ascorbic acid, adrenaline, 5-hydroxytryptamine, and glutathione) was enhanced up to 71-fold. Beyond complicated cascade systems requiring at least two nanozymes, sophisticated artificial recognition via multiple interactions was simplified by exploiting the oxidative properties of product intermediates; thus, only a single common oxidase-like nanozyme was needed. This work offers a new strategy to enhance the selectivity of nanozymes for bioanalytical applications.
Oligo[n]rotaxanes are one of the most extensively studied categories of mechanically bonded macromolecules. In this study, a supramolecular oligo[2]rotaxane is successfully constructed driven by platinum(Ⅱ) metallacycle and pillar[5]arene-based host–guest interactions in an orthogonal way. The supramolecular oligo[2]rotaxane is further applied in fabricating a light harvesting system.
Trifluoroacetic acid (TFA) catalyzed condensation reaction between tetraaminooxacalix[4]arene and N-alkylcarbazole-3,6-dicarbaldehyde in CH2Cl2 afforded a single product in 87%–89% yield. Well-defined yet undissolvable 1H NMR spectra suggested formation of robust and discrete structures in solution. X-ray single crystal analysis further revealed a giant twisted double-layer chiral macrocycle in the solid state, which was formed from [4 + 8] condensation of the two reactants via 16 imine bonds. DFT calculations discovered that only the [4 + 8] twisted product is thermodynamically favorable, which accounts for its highly selective and efficient formation out of a library of many other combinations.
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