Xiaoxia Feng,Pengxiao Xu,Jinli Liu,Xiyue Zhao,Jing Cao,Jiacheng Liu
Zero-dimensional Cs4PbBr6 nanocrystals (NCs) possess attractive photoluminescence (PL) properties and feature facile chemical synthesis, making them promising for application in luminescent materials. However, Cs4PbBr6 remains sensitive to polar solvents and thermal stimuli because of soft ionic nature of Cs4PbBr6 and dynamic behavior of surface ligands. Herein, a strategy controlled by an in situ surface coordination reaction is developed to fabricate stable NCs with a Cs4PbBr6-Zn(moi)2 core–shell structure. It was found that the Cs4PbBr6 surface regulated by the use of 2-mercaptoimidazole (called moi) and the coordination between the −NH group of moi and Zn2+ is critical for the formation of Cs4PbBr6-Zn(moi)2 core–shell NCs. Meanwhile, the thickness of the Zn(moi)2 shell can be facilely controlled by the growth time because of the solubility of moi and Zn(OAc)2·2H2O in ethyl acetate. Compared to bare Cs4PbBr6, Cs4PbBr6-Zn(moi)2 NCs exhibited highly improved polar solvent resistance and thermal stability. By combining the sensitivity of Cs4PbBr6 and the stability of Cs4PbBr6-Zn(moi)2, we used two NCs as PL security inks to fabricate optical anticounterfeiting labels. Thus, the disposable or reusable optical anticounterfeiting label is achieved by changing the external dual-stimuli. This work provides a novel strategy to enhance the stability of Cs4PbBr6 and develop its potential interest for application in anticounterfeiting technologies.
The novel phage ST-3, capable of infecting the foodborne pathogen Salmonella Typhimurium, was isolated from wastewater. The Biological characters and genome information of ST-3 were analyzed. In the in vitro assay, the phage ST-3 with a MOI of 10 effectively inhibited the growth of Salmonella Typhimurium CGMCC 1.1174 in 6 h. The inhibitory effect of combination phage ST-3 and antibiotics was also studied, the removal rate of planktonic host exposed to ST-3 and levofloxacin hydrochloride at the same time, or to ciprofloxacin followed by ST-3, is higher than that exposed to antibiotic dosing group alone and antibiotic + phage dosing group. The phage ST-3 combined with 0.5 µg/mL levofloxacin hydrochloride resulted in the largest decrease in biofilm biomass at 54%. The phage ST-3 could be a potential agent to control Salmonella Typhimurium growth and provide instruction for use it and antibiotics together.
Natural Bombyx mori silk fibroin (SF) fibers were modified with 2-methacryloyloxyethyl isocyanate (MOI) first for the introduction of vinyl groups. Then, 1H,1H,2H,2H-perfluorodecanethiol was grafted onto the SF fibers via thiol-ene click chemistry using ultraviolet light. The formations of MOI-modified and PFDT-grafted SF fibers were analyzed using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The morphology of samples was also revealed by a scanning electron microscope. In addition, differential scanning calorimetry results demonstrated that SF fibers did not show significant change in thermal behavior, regardless of the chemical modification. To confirm the cytotoxicity of the prepared SF fibers, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay was performed, and no toxicity was observed with PFDT-grafted SF fibers. The results also showed that PFDT-grafted SF fibers exhibited good antifouling properties when Chlorella vulgaris (C. vulgaris) was selected as a model for algal cells adhesion experiment.
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