- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Facile green synthesis and antimicrobial performance of Cu2O nanospheres decorated g-C3N4 nanocomposite
摘要： In recent years, biosynthesis and green chemistry are the novel approach for the fabrication of nanoparticles. Cu2O nanospheres decorated graphitic carbonitride (g-C3N4) nanocomposite have been synthesized by hydrothermal method using extracts of Citrus limon leaves which acts as reducing and stabilizing elements for the biosynthesis of nanoparticles. The comparative antimicrobial assay of different mass percentage(1%,5%,10%) of Cu content in the nanocomposites revealed that the CuCN10 has the more effective zone of inhibition due to their average particle size range 2–10nm. The addition of g-C3N4 as a support for the Cu2O photocatalyst helps in enhancing the charge transfer and improving photocatalytic degradation of contaminants and microorganisms. Moreover, the synthesized composite showed good antibacterial properties against both Gram-negative and Gram-positive bacterial strains.
关键词： biosynthesis,zone of inhibition.,green chemistry,Citrus limon,photocatalyst,antimicrobial activity
更新于2025-09-23 15:23:52
-
DWARF4 accumulation in root tips is enhanced via blue light perception by cryptochromes
摘要： Brassinosteroid (BR) signalling is known to be coordinated with light signalling in aboveground tissue. Many studies focusing on the shade avoidance response in aboveground tissue or hypocotyl elongation in darkness have revealed the contribution of the BR signalling pathway to these processes. We previously analysed the expression of DWARF 4 (DWF4), a key BR biosynthesis enzyme, and revealed that light perception in aboveground tissues triggered DWF4 accumulation in root tips. To determine the required wavelength of light and photoreceptors responsible for this regulation, we studied DWF4-GUS marker plants grown in several monochromatic light conditions. We revealed that monochromatic blue LED light could induce DWF4 accumulation in primary root tips and root growth as much as white light, while monochromatic red LED could not. Consistent with this, a cryptochrome1/2 double mutant showed retarded root growth under white light while a phytochromeA/B double mutant did not. Taken together, our data strongly indicated that blue light signalling was important for DWF4 accumulation in root tips and root growth. Furthermore, DWF4 accumulation patterns in primary root tips were not altered by auxin or sugar treatment. Therefore, we hypothesize that blue light signalling from the shoot tissue is different from auxin and sugar signalling.
关键词： light signalling,brassinosteroid,DWF4,phytochromes,cryptochromes,hypocotyl elongation,photoreceptor,root growth,BR biosynthesis
更新于2025-09-23 15:22:29
-
Extracellular biosynthesis of Cu2-xSe nanocrystallites with photocatalytic activity
摘要： Semiconductor Cu2-xSe nanospheres were successfully biosynthesized based on bioreduction of SeO3 2? into Se2? by the selenite-reducing bacterium, Pantoea agglomerans. The Cu2-xSe nanospheres had excellent crystallinity with a face-centered cubic structure and an average diameter of 80 nm. Composition and oxidation states analysis using X-ray photoelectron spectroscopy and X-ray energy dispersive spectroscopy followed by optical characterization using ultraviolet-visible and Fourier transform infra-red spectroscopy confirmed that the biosynthesized Cu2-xSe nanospheres were capped by proteins. The extracellular proteins which mediated biosynthesis were visualized by excitation–emission matrix fluorescence spectroscopy. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis revealed that the molecular masses of proteins were about 110, 50, 38, 35 and 25 kDa. The biosynthesized Cu2?xSe nanospheres showed an excellent and stable photocatalytical activity under sunlight irradiation in the degradation of methylene blue for four cycles. This study put forward a green and toilless way to manufacture copper selenide nanoparticles using a biological process.
关键词： Biosynthesis,Photocatalytical activity,Cu2-xSe,Extracellular proteins
更新于2025-09-23 15:21:21
-
Effects of reaction conditions on light-dependent silver nanoparticle biosynthesis mediated by cell extract of green alga Neochloris oleoabundans
摘要： Silver nanoparticles (AgNPs) were synthesized by incubating the mixture of AgNO3 solution and whole-cell aqueous extracts (WCAEs) of Neochloris oleoabundans under light conditions. By conducting single-factor and multi-factor optimization, the effects of parameters including AgNO3 concentration, pH, and extraction time were quantitatively evaluated. The optimal conditions in terms of AgNP yield were found to be 0.8 mM AgNO3, pH 5, and 9-h extraction. The AgNPs thus synthesized were quasi-spherical with a mean particle diameter of 16.63 nm and exhibited decent uniformity as well as antibacterial activities, which may facilitate AgNP biosynthesis’s application in the near future.
关键词： Extraction time,Biosynthesis,Silver nanoparticles,Light-dependent reaction,AgNO3 concentration,pH,Microalgae
更新于2025-09-23 15:21:21
-
Double Fano resonances in hybrid disk/rod artificial plasmonic molecules based on dipole-quadrupole coupling
摘要： Fano resonance can be achieved by the destructive interference between a superradiant bright mode and a subradiant dark mode. A variety of artificial plasmonic oligomers have been fabricated to generate Fano resonance for its extensive applications. However, the Fano resonance in plasmonic oligomer systems comes from the interaction of all metal particles, which greatly limits the tunability of the Fano resonance. Besides, only a single Fano resonance is supported by many existing plasmonic oligomers, while multiple Fano resonances mostly occur in complex and multilayer structures, whose fabrication is greatly challenging. Here, a simple asymmetric plasmonic molecule consisting of a central metal disk and two side-coupled parallel metal rods is demonstrated. The simulation and experimental results clearly show that double Fano resonances appear in the transmission spectrum. In addition, the two Fano peaks can be independently tuned and single/double Fano peak switching can be achieved by changing one rod length or the gap distances between the rods and the disk. The modulation method is simple and effective, which greatly increases the tunability of the structure. The proposed asymmetric artificial plasmonic molecule can have applications in multi-channel optical switches, filters and biosensors. Moreover, the controllable plasmonic field intensity in the gap between the disk and rods also provides a new control means for plasmon-induced photocatalytic reactions and biosynthesis.
关键词： plasmonic oligomers,biosynthesis,Fano resonance,filters,optical switches,biosensors,asymmetric plasmonic molecule,plasmon-induced photocatalytic reactions,double Fano resonances
更新于2025-09-23 15:19:57
-
Fungal In Situ Assembly Gives Novel Properties to CdS <sub/><i>x</i> </sub> Se <sub/> 1a?? <i>x</i> </sub> Quantum Dots for Sensitive Label-Free Detection of Chloramphenicol
摘要： Quantum dots (QDs) are attracting significant attention for the development of sensitive detection methods because of their unique optical properties. Biosynthetic QDs using organisms is a promising alternative route to chemical synthesis because it is a simple and eco-friendly process. Herein, we developed a straightforward and green system for the biological assembly of CdSxSe1?x QDs by Phomopsis sp. XP-8 within 6 h, a more efficient approach than those reported in other organisms. The QDs were shown to have a CdS0.75Se0.25@oligopeptide transporter structure, and the production process was shown to be strongly influenced by intracellular glutathione content. The QDs were monodispersed with a uniform spherical shape of 3.22 ± 0.07 nm in diameter. They exhibited good water solubility and excellent fluorescence properties. The QDs could be extracted and used directly as a sensitive chloramphenicol (CAP) probe via static fluorescence quenching in the linear range from 3.13 to 500 μg/L with a detection limit of 0.89 μg/L. The detection method was highly selective for CAP with minimal interference from other antibiotics and was used to successfully detect CAP in milk samples. Overall, this work has great significance for the development of a fast and simple QD synthesis system via biological assembly.
关键词： Phomopsis sp. XP-8,Chloramphenicol,CdSxSe1?x quantum dots,Biosynthesis,Label-free detection
更新于2025-09-23 15:19:57
-
N,S-self-doped carbon quantum dots from fungus fibers for sensing tetracyclines and for bioimaging cancer cells
摘要： In this work, nitrogen and sulfur dual-doped carbon quantum dots (N,S-CDs) from naturally renewable bio-material fungus fibers were prepared by a biosynthesis and hydrothermal method. The N,S-CDs displayed good water solubility, excellent stability, high quantum yield (QY = 28.11%) as well as remarkable features for fluorescence quenching-based detection and cellular imaging of cancer cells. It was worth mentioning that the heteroatoms doped carbon quantum dots made from the fungus fibers had a satisfactory QY and could be used as a selective, efficient, and sensitive fluorescent probe to determine tetracyclines by the synergistic effects of static quenching and internal filtration effect. The probe demonstrated a wide linear range and low detection limit. For tetracycline, the linear range was 0.5 μM to 47.6 μM, and the corresponding detection limit was 15.6 nM. Significantly, the test papers prepared by using N,S-CDs could detect tetracyclines in aquiculture wastewater rapidly. The produced N,S-CDs did not affect the cell viability and showed great promises for cellular imaging.
关键词： Biosynthesis,Cellular imaging,Tetracyclines,Fungus fibers,N,S-self-doped carbon dots
更新于2025-09-19 17:13:59
-
Color Development and Phytochemical Changes in Mature Green Chili (Capsicum annuum L.) Exposed to Red and Blue Light-Emitting Diodes
摘要： Exposure of mature green ‘Takanotsume’ chili fruit to blue and red light-emitting diodes (LEDs) was investigated. The red LED accelerated the red color development of chili as indicated by higher a* and chroma values, as well as lower hue angle and total chlorophyll compared to the blue LED and darkness (control). These were linked to increases in β-carotene, free-capsanthin and total carotenoids. The carotenoid biosynthesis-related genes: lycopene-β-cyclase (Lcyb), β-carotene hydroxylase (CrtZ), and capsanthin/capsolubin synthase (Ccs) were up-regulated by the red LED after 2 days of the experiment. The blue LED was more effective in increasing the expression of the phytoene synthase (Psy) gene at day 1 of experiment. The total phenolic, vitamin C content, and antioxidant capacity were also higher in the blue LED-treated chili. Results suggest that the responses of each carotenoid-related gene to the light wavelengths and the accumulation of phytochemicals are specific characteristics of this chili cultivar.
关键词： phytochemicals,carotenoids,LEDs,carotenoid biosynthesis,mature green chili,Antioxidant
更新于2025-09-12 10:27:22
-
Single-step biosynthesis of Ag/AgCl@TiO2 plasmonic nanocomposite with enhanced visible light photoactivity through aqueous leaf extract of a mangrove tree
摘要： Ag/silver halides have recently received attention in the synthesis of heterostructured nanocomposites. Although important, the green biosynthesis of Ag/silver halide nanocomposites has not yet been reported. Herein, a simple, single-step biosynthesis process was implemented using aqueous leaf extract (ALE) of the mangrove Avicennia marina to synthesize Ag/AgCl@TiO2 plasmonic nanocomposites with enhanced visible light photoactivity. Characterization results showed that the ALE was necessary for nanocomposites preparation as a reducing and stabilizing agent. With increase in the ALE/AgNO3 ratio (R1) of the initial precursor from 0 to 1.63, the diffraction peaks of Ag/AgCl became visible slowly and their intensity increased. Besides, AgNO3/tetraethylorthotitanate ratio (R2) had a positive effect on increasing the intensity of Ag/AgCl diffraction peaks. The UV light absorption intensity of Ag/AgCl@TiO2 was improved and displayed stronger absorption by increasing R1 values. A broad absorption peak was recorded in the visible wavelength spectrum of the biosynthesized nanocomposites from 400 to 600 nm, centered at 500 nm, which could be associated with the surface plasmon resonance effect of spatially detained electrons in Ag/AgCl nanocrystals. This enhanced absorption showed the photoactivity of the biosynthesized nanocomposites in the visible light region, which was confirmed in a real application for degradation of eosin Y with 99.8% efficiency under sunlight. Thus, it seems that the biological procedure, which is environmentally friendly and inexpensive, could replace the conventional approaches to synthesize Ag/AgCl@TiO2 plasmonic nanocomposites with enhanced visible light photoactivity.
关键词： Surface plasmonic resonance,Semiconductors,Visible light,Biosynthesis,Avicennia marina
更新于2025-09-12 10:27:22
-
Enzyme-Catalyzed in Situ Synthesis of Temporally and Spatially Distinct CdSe Quantum Dots in Biological Backgrounds
摘要： The cellular machinery of metal metabolism is capable of making a wide range of inorganic nanoparticles and quantum dots. Individual enzymes from these metabolic pathways are being identified with metal reducing activity, and some have been isolated for in situ particle formation and labeling. We previously identified a glutathione reductase like metalloid reductase (GRLMR) from Pseudomonas moravenis stanleyae with a high affinity for the bioavailable selenium thiolate selenodiglutatione and exhibiting NADPH-dependent reduction of selenodiglutathione to Se(0), initiating the growth of pure selenium metal nanoparticles. In this study, we demonstrate that the GRLMR enzyme can further reduce selenium to a Se(2?) oxidative state, which is capable of nucleating with Cd(2+) to rapidly form CdSe quantum dots. We show that GRLMR can outcompete background sources of cellular selenium reduction (such as glutathione) and can control the kinetics of quantum dot formation in complex media. The resulting particles are of smaller diameter, with a distinguishingly shifted emission spectrum and superior full width at half-maximum. This study indicates that there is great potential for using GRLMR to study and design enzymes capable of controlled biosynthesis of nanoparticles and quantum dots, paving the way for cellularly assembled nanoparticle biosensors and reporters.
关键词： enzyme-catalyzed,CdSe quantum dots,nanoparticle biosynthesis,GRLMR,biological backgrounds,selenium reduction
更新于2025-09-12 10:27:22