Curcumin is a plant‐derived polyphenolic active substance with broad‐spectrum antibacterial properties. Curcumin blocks bacterial growth owing to its structural characteristics and the generation of antioxidation products. Curcumin can inhibit bacterial virulence factors, inhibit bacterial biofilm formation and prevent bacterial adhesion to host receptors through the bacterial quorum sensing regulation system. As a photosensitizer, curcumin acts under blue light irradiation to induce phototoxicity and inhibit bacterial growth. Moreover, it can exert a synergistic antibacterial effect with other antibacterial substances. In this review, we summarize the research progress on the antibacterial mechanism of curcumin based on five targeting structures and two modes of action. Our discussion provides a theoretical basis and technical foundation for the development and application of natural antibacterial agents.
Hybrid composites of CdS nanoparticles embedded in sulfonated polystyrene (PS) matrixes have been prepared and characterized. The -SO 3groups acted as the coordination sites for cadmium ion aggregations and nanosized CdS particles were successfully grown in situ at these sites with the release of S 2ions from thioacetamide. The density and size of the nanoparticles were found to be a function of the sulfonate content of PS and the concentration of Cd 2+ feed ions used. Ionic clusterings within the polymer matrix occurred at a sulfonate content of 9.9 mol % and has provided a confined medium for particle growth in uniform size. The optical properties of the prepared CdS-PS hybrid composites were characterized by linear absorption and fluorescence spectra. Z-scan measurement was also employed to investigate the nonlinear optical properties at a wavelength of 532 nm. The results showed that the nonlinear refractive index of the composite varies with the input irradiance, thus indicating not just third-order but possible higher order nonlinearity.
Tunable gating graphene oxide (GO) membranes with high water permeance and precise molecular separation remain highly desired in smart nanofiltration devices. Herein, bioinspired by the filtration function of the renal glomerulus, we report a smart and high-performance graphene oxide membrane constructed via introducing positively charged polyethylenimine-grafted GO (GO-PEI) to negatively charged GO nanosheets. It was found that the additional GO-PEI component changed the surface charge, improved the hydrophilicity, and enlarged the nanochannels. The glomerulus-inspired graphene oxide membrane (G-GOM) shows a water permeance up to 88.57 L m–2 h–1 bar–1, corresponding to a 4 times enhancement compared with that of a conventional GO membrane due to the enlarged confined nanochannels. Meanwhile, owing to the electrostatic interaction, it can selectively remove positively charged methylene blue at pH 12 and negatively charged methyl orange at pH 2, with a removal rate of over 96%. The high and cyclic water permeance and highly selective organic removal performance can be attributed to the synergic effect of controlled nanochannel size and tunable electrostatic interaction in responding to the environmental pH. This strategy provides insight into designing pH-responsive gating membranes with tunable selectivity, representing a great advancement in smart nanofiltration with a wide range of applications.
Cross-linked protein crystal technology, as either a protein stabilisation or enzyme immobilisation method, has garnered more attention recently. This method not only can retain the original activity of the protein molecule but can also significantly enhance the crystals' mechanical and chemical stability. This review presents the preparation and mechanism of cross-linked protein crystals using glutaraldehyde. The mechanical, chemical and thermal properties of the cross-linked protein crystals are also reviewed in detail. In addition, this paper summarises the applications of cross-linked protein crystals in the fields of materials science, biosensors, chromatographic analysis, oral delivery and protein crystal quality improvement. Finally, the limitations and perspectives on cross-linked protein crystals are presented.Crystallisation is a well-known approach to obtain highly puri-ed proteins. During crystallisation, protein molecules can be Fig. 2 A schematic diagram of the polymerisation of glutaraldehyde. 21This journal is
Titanium has been widely used as a dimensionally stable anode in the electrolysis industry because of its excellent corrosion resistance, conductivity, and scalability. However, because of its poor biocompatibility and poor performance as a bioanode, it has drawn little attention in the field of microbial fuel cells (MFCs). This study reports an efficient way to convert a titanium electrode into a high-performance anode for MFCs, in situ growth of titanium dioxide nanotubes (TNs) on its surface. After TN modification, the titanium surface became rougher, more hydrophilic, and more conducive for anodic biofilm formation. The maximal current density achieved on this TNmodified titanium electrode was 12.7 A m −2 , which was 190-fold higher than that of the bare titanium electrode and even higher than that of the most commonly used carbon felt electrode. Therefore, the high conductivity, corrosion resistance, and current density make the TN-modified titanium electrode a promising and scalable anode for MFCs.
Recent advances in polymer acceptors that focus on structure–property relationships, which may provide guidance for photovoltaic materials, were systematically summarized.
During this study, fresh mangoes were packed into multilayer coatings made from chitosan containing cinnamon essential oil microcapsules and alginate solutions that were alternately deposited on the mango surfaces by electrostatic interaction. We then compared the physical and chemical indexes to examine the changes in the mangoes during 14 d of storage. The results showed that the microcapsules prepared in the experiment were of uniform size, with the sustained release of essential oil exceeding 168 h. Compared with uncoated mangoes, the mangoes coated with the coatings could effectively inhibit the decrease of the titratable acid, soluble solids, and vitamin C contents; slow down the increase of the weight loss and pH; delay the appearance of mango respiration peaks; and preserve the firmness at storage conditions of 25 °C and 50% RH. Our findings revealed that mangoes without treatment showed losses in their edible and commercial value after 14 days in storage, and the mangoes coated with five layers still retained food and commercial value. Cross-sectional scanning electron microscopy images of the coatings showed that they had distinct layers and were of good uniformity and tight binding, and they also had good adhesion to the mango surface. These findings provide important insights into the use of coatings for the packaging of fruits during storage, which is essential for promoting the application of coatings for packaging preservation without big cost and expensive equipment.
This review summarizes the preparation methods of cellulose nanofibrils (CNFs) and the progress in the research pertaining to their surface modification. Moreover, the preparation and surface modification of nanocellulose were comprehensively introduced based on the existing literature. The review focuses on the mechanical treatment of cellulose, the surface modification of fibrillated fibers during pretreatment, the surface modification of nanocellulose and the modification of CNFs and their functional application. In the past five years, research on cellulose nanofibrils has progressed with developments in nanomaterials research technology. The number of papers on nanocellulose alone has increased by six times. However, owing to its high energy consumption, high cost and challenging industrial production, the applications of nanocellulose remain limited. In addition, although nanofibrils exhibit strong biocompatibility and barrier and mechanical properties, their high hydrophilicity limits their practical application. Current research on cellulose nanofibrils has mainly focused on the industrial production of CNFs, their pretreatment and functional modification and their compatibility with other biomass materials. In the future, with the rapid development of modern science and technology, the demand for biodegradable biomass materials will continue to increase. Furthermore, research on bio-based nanomaterials is expected to advance in the direction of functionalization and popularization.
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