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Effect of Polymer Capping on Photonic Multi-Corea??Shell Quantum Dots CdSe/CdS/ZnS: Impact of Sunlight and Antibacterial Activity
摘要： The highly luminescent CdSe/CdS/ZnS core?multi-shell quantum dots (QDs) were prepared without a protective atmosphere through the precursor injection method (phosphine free) in paraffin liquid and oleic acid. Polymers (PEG, PVA, PVP, and PAA) were coated to CdSe/CdS/ZnS core?multi-shell quantum dots to increase stability. However, core?multi-shell structured QDs reveal enhanced emission in the range 355?410 nm by suppressing the defect sensitive cores and nonradioactive recombination in PL spectra. The cubic zinc blended quantum dots with crystallite size in the range 22?44 nm, as confirmed by XRD, were obtained. The resultant absorption spectra of all the samples showed that the samples were absorbent in the UV region over the 302?380 nm range. In the FT-IR spectrum 712, 731, and 400?700 cm?1 band values were assigned to CdSe, CdS, and ZnS band stretching, respectively. Images of CdSe, CdSe/CdS, and CdSe/CdS/ZnS quantum dots obtained from the SEM were spherical whereas QDs capped with different polymers (PEG, PVA, PVP, and PAA) showed nanofibers that were linear and homogeneous size ranged between 12 and 38 nm. These as prepared QDs were placed under visible light for 48 h. After absorbing UV light, the range of UV?vis intensity was enhanced until 389?464 nm and emission intensity enhanced until 492?509 nm, which was confirmed by UV and PL spectra. CdSe/CdS/ZnS QDs with organic ligands revealed antibacterial activity over a broad range against Klebsiella Pneumoniae and Pseudomonas aeruginosa.
关键词： CdSe/CdS/ZnS,Photoluminescence,Polymer capping,Quantum dots,Antibacterial activity
更新于2025-09-23 15:19:57
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A Novel Biocompatible Titaniuma??Gadolinium Quantum Dot as a Bacterial Detecting Agent with High Antibacterial Activity
摘要： In this study, the titanium–gadolinium quantum dots (TGQDs) were novel, first of its type to be synthesized, and fully characterized to date. Multiple physical characterization includes scanning electron microscopy (SEM), scanning electrochemical microscope (SCEM), x-ray fluorescence, spectrophotometry, and dynamic light scattering were carried out. The obtained results confirmed appropriate size and shape distributions in addition to processing optical features with high quantum yield. The synthesized TGQD was used as a fluorescent dye for bacterial detection and imaging by fluorescent microscopy and spectrophotometry, where TGQD stained only bacterial cells, but not human cells. The significant antibacterial activities of the TGQDs were found against a highly pathogenic bacterium (Staphylococcus aureus) and its antibiotic resistant strains (vancomycin and methicillin resistant Staphylococcus aureus) using growth curve analysis and determination of minimum inhibitory concentration (MIC) analysis. Live/dead cell imaging assay using phase-contrast microscope was performed for further confirmation of the antibacterial activity. Cell wall disruption and release of cell content was observed to be the prime mode of action with the reduction of cellular oxygen demand (OD).
关键词： titanium–gadolinium quantum dots,bacterial resistance,antibacterial activity,bacterial detection,SECM
更新于2025-09-23 15:19:57
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Sustainable Scientific Advancements modified Ag2O-ZnO thin films characterization and application of photocatalytic purification of carcinogenic dye in deionizer water and contaminated sea water solutions and Synthetic, Natural based Dye-Sensitized Solar Cells
摘要： The manuscript studied the preparation of ZnO as well as Ag2O-ZnO thin films deposited on glass substrates by spray pyrolysis approach at 500oC. The photocatalytic activity of Ag2O-ZnO nanocomposite material was studied via the Photodegradation reaction of Rhodamine B (Rh B) dye under UV-light irradiation in Deionizer water which shows high activity as compared by Contamination of sea water. The Zinc was Zincacetylacetonate (Zn C10 H14 O5) at the atomic concentration and then dissolved in the ethanol and Ag NO3 (0.1 M) dissolved in ethanol. The effect of silver Oxide - Zinc Oxide Nanocomposite material on the structural, surface morphological, electrical and optical properties of Ag2O-ZnO thin films were studied. HR-SEM and HR-TEM image shows exposed that the surface morphology of the films nanoflower shaped structure. The presence of Silver, Zinc and Oxygen are confirmed the presence of peaks, using EDS analysis. X-ray diffraction (XRD) patterns accepted the successful growth of high quality thin films which is polycrystalline nature. The PL analysis shows in Ag2O-ZnO is certified to the low recombination of electron-hole pairs by transfer of electrons and holes between ZnO and UV-Vis DRS analysis. The photocatalytic activity of Ag2O-ZnO nanocomposite material was studied from Photodegradation study of Rhodamine B (Rh B) dye under UV-light irradiation of Deionizer water was high activity that Contamination of sea water. As a reaction of this the material was found to be stable and reusable, which extends to a high antibacterial activity and the electrochemical study from synthetic based and Natural based DSSCS analysis showed increased current is short circuit by Ag2O-ZnO thin film nanocomposite material was industrial applications.
关键词： Spray pyrolysis,Photocatalytic activity,Electrochemical activity,Antibacterial activity
更新于2025-09-16 10:30:52
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Controlled Synthesis of Triangular Silver Nanoplates by Gelatin–Chitosan Mixture and the Influence of Their Shape on Antibacterial Activity
摘要： Triangular silver nanoplates were prepared by using the seeding growth approach with the presence of citrate-stabilized silver seeds and a mixture of gelatin–chitosan as the protecting agent. By understanding the critical role of reaction components, the synthesis process was improved to prepare the triangular nanoplates with high yield and e?ciency. Di?erent morphologies of silver nanostructures, such as triangular nanoplates, hexagonal nanoprisms, or nanodisks, can be obtained by changing experimental parameters, including precursor AgNO3 volume, gelatin–chitosan concentration ratios, and the pH conditions. The edge lengths of triangular silver nanoplates were successfully controlled, primarily through the addition of silver nitrate under appropriate condition. As-prepared triangular silver nanoplates were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), UV-Vis, Fourier transform infrared spectroscopy (FT-IR), and X-Ray di?raction (XRD). Silver nanoplates had an average edge length of 65–80 nm depending on experimental conditions and exhibited a surface plasma resonance absorbance peak at 340, 450, and 700 nm. The speci?c interactions of gelatin and chitosan with triangular AgNPs were demonstrated by FT-IR. Based on the characterization, the growth mechanism of triangular silver nanoplates was theoretically proposed regarding the twinned crystal of the initial nanoparticle seeds and the crystal face-blocking role of the gelatin–chitosan mixture. Moreover, the antibacterial activity of triangular silver nanoplates was considerably improved in comparison with that of spherical shape when tested against Gram-positive and Gram-negative bacteria species, with 6.0 ug/mL of triangular silver nanoplates as the MBC (Minimum bactericidal concentration) for Escherichia coli and Vibrio cholera, and 8.0 ug/mL as the MBC for Staphylococcus aureus and Pseudomonas aeruginosa. The MIC (Minimum inhibitory concentration) of triangular Ag nanoplates was 4.0 ug/mL for E. coli, V. cholera, S. aureus, and P. aeruginosa.
关键词： seeding growth approach,triangular silver nanoplates,gelatin,antibacterial activity
更新于2025-09-16 10:30:52
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Extracellular biosynthesis of cadmium sulphide quantum dot using cell-free extract of Pseudomonas chlororaphis CHR05 and its antibacterial activity
摘要： For the ?rst time a novel aquatic bacterium belonging to strain of Pseudomonas chlororaphis was developed for the synthesis of cadmium sul?de quantum dots. The cadmium sulfate solution incubated with cell-free extract (CFE) of P. chlororaphis strain CHR05 to generate cadmium sul?de nanoparticles (CdSNps) which were characterized with combined spectroscopy and microscopy analyses. The preliminary con?rmation on the formation of CdSNps was done by UV–vis and ?uorescence analyses with the absorption and emission spectra at 435 and 475 nm, respectively. EDX pattern shows that the CdSNps are composed of the elementals Cd and S. Also, XRD analysis of the puri?ed nanoparticles con?rmed the formation of CdSNps. FE-SEM, TEM, and DLS analyzed the size and morphology of the CdSNps. The biosynthesis of CdSNps with the strategy of cell free extract was investigated under optimum conditions. After 24 h of incubation, the results showed that the novel isolated strain can produce spherical CdSNps with an average size of 6.7 ± 2.4 nm, after exposure to CdSO4 solution (2.5 mM) at pH 7.5 and 30 °C. The antibacterial activity CdSNps against some Gram-positive and -negative bacteria were determined using agar well di?usion method and microplate method which has growth-inhibitory e?ect all on tested bacteria.
关键词： CdSNps,Cell-free extract,P. chlororaphis strain CHR05,Antibacterial activity
更新于2025-09-12 10:27:22
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NIR‐Laser‐Controlled Hydrogen‐Releasing PdH Nanohydride for Synergistic Hydrogen‐Photothermal Antibacterial and Wound‐Healing Therapies
摘要： For decades, hydrogen (H2) gas has been recognized as an excellent antioxidant molecule that holds promise in treating many diseases like Alzheimer’s, stroke, cancer, and so on. For the first time, active hydrogen is demonstrated to be highly efficient in antibacterial, antibiofilm, and wound-healing applications, in particular when used in combination with the photothermal effect. As a proof of concept, a biocompatible hydrogen-releasing PdH nanohydride, displaying on-demand controlled active hydrogen release property under near-infrared laser irradiation, is fabricated by incorporating H2 into Pd nanocubes. The obtained PdH nanohydride combines both merits of bioactive hydrogen and photothermal effect of Pd, exhibiting excellent in vitro and in vivo antibacterial activities due to its synergistic hydrogen-photothermal therapeutic effect. Interestingly, combinational hydrogen-photothermal treatment is also proved to be an excellent therapeutic methodology in healing rats’ wound with serious bacterial infection. Moreover, an in-depth antibacterial mechanism study reveals that two potential pathways are involved in the synergistic hydrogen-photothermal antibacterial effect. One is to upregulate bacterial metabolism relevant genes like dmpI, narJ, and nark, which subsequently encode more expression of oxidative metabolic enzymes to generate substantial reactive oxygen species to induce DNA damage and another is to cause severe bacterial membrane damage to release intracellular compounds like DNA.
关键词： wound healing,hydrogen releasing materials,synergistic hydrogen-photothermal therapy,antibacterial mechanism,antibacterial activity
更新于2025-09-11 14:15:04
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In Situ Monitoring of the Antibacterial Activity of a Copper–Silver Alloy Using Confocal Laser Scanning Microscopy and pH Microsensors
摘要： The antibacterial efficacy of a copper–silver alloy coating under conditions resembling build up of dry surface bacterial biofilms is successfully demonstrated according to US EPA test methods with a ≥99.9% reduction of test organisms over a 24 h period. A tailor-made confocal imaging protocol is designed to visualize in situ the killing of bacterial biofilms at the copper–silver alloy surface and monitor the kinetics for 100 min. The copper–silver alloy coating eradicates a biofilm of Gram-positive bacteria within 5 min while a biofilm of Gram-negative bacteria are killed more slowly. In situ pH monitoring indicates a 2-log units increase at the interface between the metallic surface and bacterial biofilm; however, the viability of the bacteria is not directly affected by this raise (pH 8.0–9.5) when tested in buffer. The OH? production, as a result of the interaction between the electrochemically active surface and the bacterial biofilm under environmental conditions, is thus one aspect of the contact-mediated killing of the copper–silver alloy coating and not the direct cause of the observed antibacterial efficacy. The combination of oxidation of bacterial cells, release of copper ions, and local pH raise characterizes the antibacterial activity of the copper–silver alloy-coated dry surface.
关键词： bacterial biofilms,confocal laser scanning microscopy,copper–silver alloy,electroplating,antibacterial activity
更新于2025-09-11 14:15:04
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Double-shelled ZnSnO3 hollow cubes for efficient photocatalytic degradation of antibiotic wastewater
摘要： The production and usage of antibiotics have been increasing rapidly with the improving quality of life and the rapid development of aquaculture, thus inducing the introduction of these antibiotics residues into the environment, increasing water pollution levels. Due to bioaccumulation, bacteriostatic activity, many of these threaten aquatic and terrestrial organisms. Here we prepared double-shelled ZnSnO3 hollow cubes for efficient photocatalytic degradation of antibiotic wastewater. The ZnSnO3, synthesized via co-precipitation, shows superior performance and stability compared to that prepared by hydrothermal and template-assisted methods. The prepared ZnSnO3 effectively photocatalyzed the degradation of not only ciprofloxacin and sulfamonomethoxine pharmaceutical wastewater, but also methylene blue, rhodamine B and methyl orange dye wastewater. The hollow structure facilitates the adsorption of dye molecules and provides a better platform for direct interaction between dye molecules and photocatalysts. Moreover, the antibacterial activity test for photocatalytic degradation effluent indicated that the biotoxicity of CIP toward Escherichia coli DH5a was eliminated after the ZnSnO3 photocatalysis under simulated irradiation. This study not only demonstrates an efficient photocatalyst, but also further indicates the effectiveness of photocatalytic technology in the treatment of antibiotic wastewater.
关键词： double-shelled ZnSnO3,wastewater,ciprofloxacin,antibacterial activity,photocatalytic
更新于2025-09-11 14:15:04
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Synthesis and characterization of CuZnO@GO nanocomposites and their enhanced antibacterial activity with visible light
摘要： Copper and zinc composite oxide (CuZnO) was synthesized successfully via a sol–gel method and modi?ed by silane coupling agent to prepare CuZnO@graphene oxide (CuZnO@GO) nanocomposites, with CuZnO nanoparticles (NPs) distributed on the GO nanosheets. The structural properties of prepared CuZnO@GO nanocomposites were studied by FT-IR and XRD techniques. SEM and TEM analysis showed the spherical morphology of CuZnO NPs with a diameter of 20–40 nm. The optical properties of synthesized products were estimated through UV–Vis DRS and PL spectroscopy, which suggested that CuZnO@GO nanocomposites had a widened absorption range from UV to visible region and a lower photogenerated carrier recombination rate than that of pure CuZnO NPs. The antibacterial mechanism of CuZnO@GO nanocomposites was investigated using gram-negative bacteria Escherichia coli and gram-positive bacteria Staphylococcus aureus as two model microorganisms. The antibacterial properties of CuZnO@GO nanocomposites on mixed bacteria were researched in the cooling water system. The results showed that when adding CuZnO@GO nanocomposites to E. coli or S. aureus suspension, the protein leakage after 20 h was 10.5 times or 8.3 times higher than that in the blank experiment. Furthermore, the antibacterial activity of CuZnO@GO nanocomposites in presence of visible light was found to be signi?cantly enhanced as compared with control. Under visible light irradiation, the antibacterial rate of CuZnO@GO nanocomposites in circulating cooling water reached 99.09% when the mass fraction of GO was 17.5%, and more than 90% of bacteria were inactivated by 100 mg L?1 CuZnO@GO nanocomposites in 60 min after four recycled runs.
关键词： Water treatment,CuZnO@GO nanocomposites,Visible light,Photocatalytic antibacterial activity,Antibacterial mechanism
更新于2025-09-10 09:29:36
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Fabrication of Ag3VO4 decorated phosphorus and sulphur co-doped graphitic carbon nitride as a high-dispersed photocatalyst for phenol mineralization and E. Coli disinfection
摘要： In this work, we have successfully anchored Ag3VO4 (AV) onto P and S co-doped g-C3N4 (PSGCN) to prepare high-dispersible AV/PSGCN photocatalyst via a deposition-precipitation method. The P and S co-doped g-C3N4 was synthesized via thermal polycondensation using hexachlorotriphosphazene (HCCP) and thiourea as precursors. AV/PSGCN was characterized using various spectral techniques. The atomic force analysis indicated that the thickness of AV/PSGCN was less than 3.0 nm. The zeta potential and Tyndall effect experiments ascertained formation of the well-dispersed suspension of AV/PSGCN in water. The co-doping resulted in lowering optical band gap of g-C3N4. The photoluminescence and electrochemical impedance analysis indicated suppression in recombination of photogenerated electron and hole pairs in AV/PSGCN. The photodegradation of phenol followed pseudo-first order kinetics. Hydroxyl radicals and holes were the two main reactive species for photodegradation of phenol. The COD, HPLC and LC-MS analyses confirmed mineralization of phenol in 6 h. Unlike conventional slurry type photo-reactors, AV/PSGCN was not magnetically agitated during photocatalytic reactions. AV/PSGCN exhibited significant antibacterial activity for E.Coli disinfection. The photodegradation of phenol and bacterial disinfection occurred through hole and hydroxyl radical formation mechanism.
关键词： Phenol degradation,Enhanced photocatalytic activity,Heterojunction formation,Ag3VO4,Antibacterial activity,Co-doped g-C3N4
更新于2025-09-10 09:29:36