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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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Creating an antibacterial surface on beta TNZT alloys for hip implant applications by laser nitriding
摘要： The National Joint Registry reported that the main causes for hip implant revision surgery include aseptic loosening, infection and adverse soft tissue reaction to particulate debris. There is a great need to improve the implant properties which can be achieved through a combined solution of beta titanium alloy (TNZT) with low elastic modulus and laser surface nitriding to improve mechanical properties and biological response. While titanium nitride (TiN) possesses good biocompatibility and remarkable antibacterial properties; its effectiveness as a coating on Ti-35Nb-7Zr-6Ta has not been investigated in relation to stem cell response and antibacterial laser power, specifically 35, 40 and 45 W. capability. TNZT surfaces were laser-nitrided in incremental Investigation included surface roughness and topography in microscale (WLI and SEM), microstructure (XRD) and wettability (water contact angle). Biological studies of the laser-nitrided surfaces included in vitro culture for 24 h using mesenchymal stem cell (MSC) fluorescence staining and Staphylococcus aureus (S. aureus) Live/Dead staining. Sample groups consisted of control base metal (BM), laser-nitrided at 35 W (LT35), 40 W (LT40) and 45 W (LT45). Results revealed that laser nitriding generates significantly rougher surfaces (Ra value of BM was 199.3 nm, LT35 was 722.8 nm, LT40 was 458.4 nm and LT45 was 1180.2 nm) with distinctive surface features (Rsk < 0 and Rku > 3). Surfaces after laser nitriding, regardless of laser power, can be tailored to become hydrophilic (27.1–34.2°). Fibre laser nitriding can be used to create antibacterial surface patterns on TNZT in a high power regime. A laser power of 45 W proved to be the most effective in this study, creating an overlapping crescent shape which becomes more obvious with increasing power. To summarise, laser-nitrided surfaces led to a significant antibacterial effect but offered no particular advantage to MSC response.
关键词： Fibre laser nitriding,TNZT,Antibacterial performance,Mesenchymal stem cell (MSC),Beta titanium
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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Precisely photothermal controlled releasing of antibacterial agent from Bi2S3 hollow microspheres triggered by NIR light for water sterilization
摘要： Microbial contamination in water has evoked worldwide attention owing to their greatest threats to the public safety. In this work, the sea urchin-like Bi2S3 hollow microspheres have been synthesized by a hard template-assisted polyol method using ZnS composite microspheres as sacri?ced template on the large scale, which shows good biocompatibility and photothermal conversion properties. Thermal-sensitive biocompatible 1-tetradecanol (TD) combined antibacterial agents (Linalool) were loaded into the hollow cavity of the sea urchin-like Bi2S3 hollow microspheres to form TD/Linalool@Bi2S3 composites. The Bi2S3 in the TD/Linalool@Bi2S3 composites can convert the absorbed NIR energy into heat energy under the irradiation of near infrared (NIR) light, which would make the temperature to reach the melting point of the TD and Linalool can be released at same time. Thus, the antibacterial agent Linalool can be precisely controlled releasing from the formed TD/Linalool@Bi2S3 composites, which provided rapid and e?ective killing outcome in vitro for Gram-negative Escherichia coli (E. coli) and Gram-positive Stahylococcus aureus (S. aureus). Additionally, the as-prepared TD/Linalool@Bi2S3 composites exhibited superior antibacterial ability as compared to antibacterial agent treatment or photothermal therapy (PTT) alone, which can be attributed to the synergistic e?ects of the NIR light driven photothermal killing and antibacterial agent releasing. It endowed that the designed TD/Linalool@Bi2S3 composites is a promising antibacterial platform for cleaning the microbial contaminated water environment, which is of great strategic signi?cance and remains a formidable challenge for practical applications.
关键词： Water sterilization,Bi2S3 hollow microspheres,Antibacterial,NIR light responsive,Precisely controlled delivery
更新于2025-09-11 14:15:04
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Hybrid Plasmonic Photoreactors as Visible Light-Mediated Bactericides
摘要： Photocatalytic compounds and complexes, such as tris(bipyridine)ruthenium(II), [Ru(bpy)3]2+, have recently received attention as light-mediated bactericides that can help to address the need for new antibacterial strategies. We demonstrate in this work that the bactericidal efficacy of [Ru(bpy)3]2+ and the control of its antibacterial function can be significantly enhanced through combination with a plasmonic nanoantenna. We report strong, visible light-controlled bacterial inactivation with a nanocomposite design that incorporates [Ru(bpy)3]2+ as photocatalyst and a Ag nanoparticle (NP) core as light-concentrating nanoantenna into a plasmonic hybrid photoreactor. The hybrid photoreactor platform is facilitated by a self-assembled lipid membrane that encapsulates the Ag NP and binds the photocatalyst. The lipid membrane renders the nanocomposite biocompatible in the absence of resonant illumination. Upon illumination, the plasmon-enhanced photoexcitation of the metal-to-ligand-charge-transfer band of [Ru(bpy)3]2+ prepares the reactive excited state of the complex that oxidizes the nanocomposite membrane and increases its permeability. The photooxidation induces the release of [Ru(bpy)3]2+, Ag+, and peroxidized lipids into the ambient medium, where they interact synergistically to inactivate bacteria. We measured seven orders of magnitude decrease in Gram-positive Arthrobacter sp. and four orders of magnitude decrease in Gram-negative Escherichia coli (E. coli) colony forming units (CFUs) with the photoreactor bactericides after 1-hour of visible light illumination. In both cases the photoreactor exceeds the bactericidal standard of a log reduction value (LRV) of 3, and surpasses the antibacterial effect of free Ag NPs or [Ru(bpy)3]2+ by more than four orders of magnitude. We also implement the inactivation of a bacterial thin film in a proof-of-concept study.
关键词： antibiotics,biofilm,controlled release,sterilization,photocatalyst,antibacterial,nanoantenna
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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Au/Ag NPS Decorated PANI For Electrochemical and Biomedical Applications
摘要： Polyaniline (PANI) has number of electronic structure and it depends on the doping. PANI composites containing Fe3O4NPs are regularly studied as the PANI having electrical and magnetic features. Herein, PANI was prepared from aniline and HCl by means of solution mixing using ammonium persulphate as oxidizing agent and catalyst. Composites of polyaniline with calcium carbonate and Au/Ag NPs were prepared. Nanocomposites of PANI were characterized using FTIR, SEM, EDX, electrical conductivity measurement techniques. The incorporation of CaCO3 and Au/Ag NPs in polyaniline matrix was confirmed by SEM, FT-IR and EDX results. CaCO3 act as binder and provide strength to the composite which can be clearly understood by SEM microgram. Electrochemical study of composite has been done which showed that on decorating PANI with gold/silver NPs, the conducting properties increases. We successfully tested the antimicrobial activity of nanocomposite via paper disk diffusion method against Escherichia coli and Staphylococcus aureus.
关键词： Antibacterial,Nanocomposite,Conducting polymer,Conductivity
更新于2025-09-10 09:29:36
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Nigella sativa seed based nanocomposite-MnO2/BC: An antibacterial material for photocatalytic degradation, and adsorptive removal of dye from water
摘要： Antimicrobial Nigella sativa seed-based nanocomposite, MnO2/BC, was synthesized and utilized for water purification through adsorption and photocatalytic degradation. MnO2/BC was prepared by co-precipitation method, and characterized using FT-IR, XRD, SEM, TEM, TGA, and DSC techniques. The composite was investigated for inhibition of bacterial cells growth. FT-IR spectrum indicated the presence of oxygenous groups on the surface; TGA and DSC showed thermal degradation; and XRD, SEM, and TEM investigations indicated amorphous, and porous nature of MnO2/BC having particle size of 190-220 nm. The nanocomposite inhibited the growth of both Gram-positive and Gram-negative bacteria cells in water. The adsorption of Methylene blue (MB) from water was investigated in batch method in terms of amount of MnO2/BC, MB concentration, pH, time, and temperature. 1.0 gL-1 of MnO2/BC removed more than 98% of MB from aqueous solution having concentration of 10 mgL-1 and pH 7.0 at 27°C. The maximum Langmuir adsorption capacity of MnO2/BC was 185.185 mgg-1 at 45°C. The adsorption was an endothermic process which obeyed Freundlich isotherm, and pseudo-second order kinetics. Therefore, the MB binding onto MnO2/BC surface was site-specific partially through weak hydrogen bonding and electrostatic interactions. The photocatalytic activity of MnO2/BC has been investigated by degrading the MB molecules/ions in water under the sunlight and 85% of degradation was achieved during 120 min irradiation. The dye was desorbed at lower pH and regenerated MnO2/BC was used for second cycle of MB adsorption. The results obtained for this study are much better than the previous MB adsorption studies with acid washed Black cumin seeds and MnFe2O4/BC for which the capacities were 73.529 mgg-1 and 10.070 mgg-1 at 27°C, respectively (J. Mol. liq. 2018a, 264, 275-284; J. Clean. Prod. 2018a, 200, 996-1008).
关键词： MnO2/BC,Antibacterial activity,Photocatalytic degradation,Adsorption,Nigella sativa plant seeds,Methylene blue
更新于2025-09-10 09:29:36
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Synthesis and characterization of TiO2/ZnCr2O4 core-shell structure and its photocatalytic and antibacterial activity
摘要： A shell of ZnCr2O4 spinel was facilely covered on the surface of TiO2 nanoparticles to synthesize TiO2/ZnCr2O4 core-shell structure using TiO2 seed particles and heterogeneous precipitation. The as-prepared nanocomposite was characterized in terms of crystal structure, morphology and surface area, light absorption and band gap. After coupling TiO2 with ZnCr2O4, a heterojunction formed between the two semiconductor materials. UV–vis absorption spectra showed a red shift of the absorption edges and lower band gap of 3.0 eV for the composite system compared to the single phase TiO2 (3.4 eV) due to the formation of new energy level at the core-shell interface. Photocatalytic activity of the nanocomposites was evaluated by degradation of methylen blue under UV-light irradiation, revealing that the core-shell nanocomosite exhibits superior photocatalytic activity (99% yield) compared to the single phase TiO2 (40% yield) even after 4 consecutive reaction runs. In fact, this enhancement was attributed to the efficient separation and migration of the photogenerated electron–hole pairs at the core-shell interface due to the formation of energy bands heterojunction at the interface. Also, it was found that the synthesized core-shell structure is a highly effective antibacterial material against E. coli bacteria.
关键词： Heterogeneous precipitation,TiO2,ZnCr2O4,Antibacterial,Photocatalyst
更新于2025-09-10 09:29:36