Systematic Structural Modification of Squaraine Dye for Near-Infrared Window One and Two Multiplexed In Vivo Imaging and Photothermal Therapy.

Due to the wide application of reporter gene-related visible/NIR-I bioluminescent imaging, multiplexed fluorescence imaging across visible/NIR-I/NIR-II has excellent potential in biomedical research. However, in vivo multiplexed imaging applications across those regions have rarely been reported due to the lack of proper fluorophores. Herein, nine squaraine dyes, which exhibit diverse adsorption and emission wavelengths, were synthesized. Among them, water-soluble SQ 710-5k and SQ 905 were found to have significant absorption differences, which allowed the tumor and lymph nodes to be identified. Then, for the first time, six-channel multiplexed fluorescence imaging across visible/NIR-I/II was achieved by coordination with reporter gene-related bioluminescent phosphors. Additional research revealed that SQ 710-5k exhibited higher-quality blood vessels and tumor imaging in NIR-II. H-aggregates SQ 905 demonstrated a high photothermal conversion efficiency for photothermal therapy. This study proposed an approach to creating small molecular dyes that coordinate with reporter gene-related bioluminescent phosphors for six-color fluorescence imaging.

Visible-light-driven water-soluble zinc oxide quantum dots for efficient control of citrus canker.

BACKGROUND: Citrus canker caused by Xanthomonas citri subsp. citri (Xcc) is a devastating bacterial disease that reduces citrus yield and quality, posing a serious threat to the citrus industry. Several conventional chemicals have been used to control citrus canker. However, this approach often leads to the excessive use of chemical agents, can exacerbate environmental pollution and promotes the development of resistant Xcc. Therefore, there is significant interest in the development of efficient and environmentally friendly technologies to control citrus canker. RESULTS: In this study, water-soluble ZnO quantum dots (ZnO QDs) were synthesised as an efficient nanopesticide against Xcc. The results showed that the antibacterial activity of ZnO QDs irradiated with visible light [half-maximal effective concentration (EC50) = 33.18 µg mL-1] was ~3.5 times higher than that of the dark-treated group (EC50 = 114.80 µg mL-1). ZnO QDs induced the generation of reactive oxygen species (•OH, •O- 2 and 1O2) under light irradiation, resulting in DNA damage, cytoplasmic destruction, and decreased catalase and superoxide dismutase activities. Transcription analysis showed downregulation of Xcc genes related to 'biofilms, virulence, adhesion' and 'DNA transfer' exposure to ZnO QDs. More importantly, ZnO QDs also promoted the growth of citrus. CONCLUSION: This research provides new insights into the photocatalytic antibacterial mechanisms of ZnO QDs and supports the development of more efficient and safer ZnO QDs-based nanopesticides to control citrus canker. © 2024 Society of Chemical Industry.

Hypsochromic Shift Donor-Acceptor NIR-II Dye for High-Efficiency Tumor Imaging.

Nowadays, second near-infrared window (NIR-II) dyes' development focuses on pursuing a longer absorption/emission wavelength and higher quantum yield, which usually means an extended π conjugation system, resulting in an enormous molecular weight and poor druggability. Most researchers thought that the reduced π conjugation system would bring on a blueshift spectrum that causes dim imaging qualities. Little efforts have been made to study smaller NIR-II dyes with a reduced π conjugation system. Herein, we synthesized a reduced π conjugation system donor-acceptor (D-A) probe TQ-1006 (Em = 1006 nm). Compared with its counterpart donor-acceptor-donor (D-A-D) structure TQT-1048 (Em = 1048 nm), TQ-1006 exhibited comparable excellent blood vessels, lymphatic drainage imaging performance, and a higher tumor-to-normal tissue (T/N) ratio. An RGD conjugated probe TQ-RGD showed an extra high contrast tumor imaging (T/N ≥ 10), further proving D-A dyes' excellent NIR-II biomedical imaging applications. Overall, the D-A framework provides a promising approach to designing next-generation NIR-II fluorophores.

Iron doped BiOBr loaded on carbon spheres for improved visible-light-driven detoxification of 2-chloroethyl sulfide.

In this study, flower-like porous iron doped bismuth oxybromide on porous activated carbon visible light catalysts (BiOBr/Fe@AC) were prepared by a reactive imidazole ionic liquid surfactant assisted solvothermal process. The morphologies, structures, optical properties and photocatalytic properties were investigated in detail. The morphology of the synthesized Fe doped BiOBr composites gradually changed from a regular spherical shape to a non-specific shape with the increase of the alkyl chain length of the ionic liquid surfactants. The photocurrent of BiOBr/Fe@AC composites is greatly influenced by the content of Fe, the type of carbon sphere and the size of the composites. The photocatalytic activity of the obtained BiOBr/Fe@AC composites was evaluated by the degradation of 2-chloroethyl sulfide (CEES) under visible light. The BiOBr/Fe@AC composites exhibited significantly enhanced photocatalytic performance compared to that of pure BiOBr and the 10.0% Fe doped BiOBr/Fe@AC composite displayed the highest photocatalytic activity. The main active species were determined to be holes and superoxide radicals by electron spin resonance (ESR) analysis and free radical trapping experiments. The introduction of iron can improve the separation and transfer rate of photoinduced charges. Carbon spheres can enhance light harvesting, improve electron transfer and increase the number of catalytic active sites. Iron and carbon embellishment is an effective strategy to enhance the photocatalytic efficiency of BiOBr. Finally, a possible photocatalytic mechanism of BiOBr/Fe@AC has been proposed.