查找使用阿拉丁产品的科研文献

Effect of the Ag+ in Ag25@ZnO nanocatalysts for the 4-nitrophenol reduction reactions

Ji Xiang,Chuancui Yang,Ke Yang,Jin Qian,Yanzhen Lu,Qihua Zhou,Fangkuo Wang

As catalysts, metal nanoclusters (NCs) have become the focus of research due to their precise structure and excellent catalytic activity. In general, it can greatly improve the catalytic activity of NCs by thermal treatment. In this work, the ZnO supported 2,4-dimethylbenzenethiol-protected-[Ag 25 (C 8 H 9 S) 18 ] - NCs (Ag 25 @ZnO) nanocatalysts were subjected to activation temperatures of 100 °C, 200 °C and 300 °C to remove the surface ligands of Ag 25  NCs and regulate the surface composition of Ag 25 @ZnO nanocatalysts. The structure of Ag 25 @ZnO nanocatalysts were characterized by XRD , SEM, TEM, EDS and XPS. In particular, the XPS results obviously confirmed that the concentration of Ag + on the catalyst surface was positively correlated with the activation temperature. Finally, the effect of the Ag  +  content on the catalytic activity of the Ag 25 @ZnO nanocatalysts was also explored. Because the content of Ag + in Ag 25 @ZnO-300 nanocatalysts is the highest, the 4-nitrophenol reduction reaction showed the best catalytic performance.

Ag/MoS2 Nanozyme Hydrogel Dressing with Adhesion and Self-Healing Properties for Antibacterial Applications

Minghui Xiao,Yan Lin,LiangHui Mei,Jian Liu,Fangbin Wang

Although considerable efforts have been devoted to this endeavor, bacterial infections and contamination of medical device surfaces and biointerfaces remain a challenge. Herein, we constructed an Ag/MoS2 nanozyme-modified hydrogel (Ag-HG) dressing with enhanced adhesion and self-healing. Ag-HG showed remarkable antibacterial effects against E. coli and Staphylococcus aureus. The Ag-HG dressing exhibited antibacterial properties with antibacterial efficacies of 72.6% and 72.7% against E. coli and Staphylococcus aureus, respectively. Moreover, this dressing disabled bacteria more efficiently with the assistance of H2O2, reaching antibacterial efficacies of 99.99% and 99.92%, respectively. Multiple modes of antimicrobial action appeared to act synergistically to inhibit microbial growth in the hydrogel dressing. Ag-HG generated reactive oxygen species to damage bacteria and trapped and confined them owing to its porous structure. The synergistic antibacterial effect of the two aspects enhanced the sterilization performance. In vivo experiments showed that the Ag-HG dressing could effectively treat skin surface wounds and accelerate wound healing. The biocompatibility of the Ag-HG dressing was verified using hematoxylin and eosin (H&E) staining. In summary, adhesion-enhanced self-healing nanozyme-modified hydrogel dressing with synergistically antibacterial activity is a promising candidate for applications that require biocompatible and antimicrobial surfaces.

Development of ZnO/Ag nanoparticles supported polydopamine-modified montmorillonite nanocomposites with synergistic antibacterial performance

Han Liang,Huiyan Wang,Xuemei Sun,Wang Xu,Na Meng,Ninglin Zhou

Nanocomposites are effective methods for the treatment of microbial infections. In this work, zinc oxide nanoparticles and silver nanoparticles were synthesized by a simple and mild method, and successfully loaded on polydopamine-modified montmorillonite (PDA Mt) to prepare nanocomposites (ZnO/Ag/PDA-Mt) with potent antibacterial ability. The transmission electron microscope (TEM) showed that the nanoparticles in ZnO/Ag/PDA-Mt were quasi-spherical, and the particle size ranged from 5 nm to 45 nm. The energy dispersive spectroscopy (EDS)-mapping verified the presence of Zn, Ag, O, Al, Si and C elements in the synthesized ZnO/Ag/PDA-Mt. In addition, the antimicrobial activity of ZnO/Ag/PDA-Mt was also tested against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). Due to the synergistic antibacterial effect between zinc oxide nanoparticles and silver nanoparticles, ZnO/Ag/PDA-Mt exhibited higher antiseptic activity than silver nanoparticles supported polydopamine-modified montmorillonite (Ag/PDA-Mt) and zinc oxide nanoparticles supported polydopamine-modified montmorillonite (ZnO/PDA-Mt). The biocompatibility of ZnO/Ag/PDA-Mt was evaluated by cytotoxicity assay. The results demonstrated that the ZnO/Ag/PDA-Mt nanocomposites have potential for antibacterial applications.

Carboxymethyl cellulose gels immobilized Ag/AgCl-ZnO nanoparticles for improving sunlight-catalyzed antibacterial performance

Chongjun Huang,Meng Xiao,Hao Cui,Jiayin Wang,Yurou Cai,Yu Ke

Antibacterial sodium carboxymethyl cellulose (CMC) gels were prepared via immobilizing ZnO and/or Ag/AgCl in situ to inhibit the aggregation of nano-photocatalyst. Epichlorohydrin was used as a crosslinking agent to prepare CMC gel, simultaneously introducing chlorine-containing branch chains as Cl reservoir to deposit AgCl. The composite gels presented pH responsive swelling properties, with the minimum swelling ratio at pH 8 and pH 4 for CMC gels containing Ag/AgCl and ZnO, respectively. Zn 2+ release from the nanocomposite gels was much greater in acidic than in neutral. Photocatalytic degradation constants of methyl orange by the composite gels under sunlight were greater than UV irradiation. Ag/AgCl loaded gel showed a degradation rate of 71.3 % under sunlight for 1 h, with a rate constant approximately 10.2 times higher than ZnO loaded gel. Extract liquids with the gel content below 0.33 mg/mL were noncytotoxicity. The nanocomposite gels presented good bactericidal rate against E. coli and S. aureus under sunlight for 6 h, comparatively to those in dark for 24 h. Bacteriostatic activity of Ag/AgCl loaded gel under sunlight for 6 h was much greater than that in dark for 24 h. The biocompatible nanocomposite gels with sunlight-catalyzed antibacterial activity would broaden the application of CMC gels.

Facile synthesis of PEG-modified fluorescent carbon dots for highly sensitive detection of Ag+

Hui Li,Changzheng Wang,Xicheng Li,Yuyi Han,Yang Zhang

Silver-based compounds are widely used in modern society. However, excessive use and uncontrollable discharging of silver ions (Ag + ) pose a potential threat to personal safety and the environment. In this work, PEG-modified fluorescent carbon dots (PEG-CDs) were synthesized through a facile solid-state reaction, exhibiting bright blue emission with a high photoluminescence quantum yield of 73.9%. The fluorescence of as-prepared PEG-CDs can be significantly quenched by the addition Ag + , showing high selectivity and sensitivity even without interference from high concentrations of other metal ions. The fluorescence intensity decreases linearly with Ag + from 0 μmol/L to 200 μmol/L with a limit of detection of 0.114 nmol/L.

Highly efficient sunlight-driven LSPR-enhanced core-shell Ag dendrite/g-C3N4 composite photocatalysts

Yuan Li,Wenyao Qian,Yong Xia,Xinxin Li,Dongmei Li,Zhiqiang Guo

Noble metal nanostructures with localized surface plasmon resonance (LSPR) effect can be employed to enhance the light absorption ability of photocatalysts . However, it has been a challenge to control the size and morphology of noble metal nanostructures to manipulate the LSPR wavelength and improve the performance of photocatalysts. Herein, an Ag dendrite (AgD) composed of Ag nanorods with different sizes was facilely constructed by a displacement reaction, and sunlight-driven LSPR-enhanced core-shell AgD/g-C 3 N 4 composite photocatalysts (AgD-CN) were synthesized by thermal polymerizing mixtures of melamine and different amounts of AgD. This core-shell AgD-CN improved the stability of AgD and made full use of the near-field enhancement effect of AgD’s LSPR, resulting in a broad light absorption band. AgD-CN-15 showed the highest photogenerated electron-hole pair separation rate and the best photocatalytic performance when the addition amount of AgD was 3 wt%. The degradation rate of RhB by AgD-CN-15 reached 95.20% after sunlight irradiation for 60 min, and its reaction rate constant was 5.2 times that of the pristine g-C 3 N 4 . Moreover, ·OH, h + and ·O 2 - were found to be the main active species. AgD is easy to prepare and can broaden the light absorption wavelength range and significantly enhance light absorption ability of photocatalysts, which provides a new method to improve the performance of LSPR-enhanced photocatalysts.

Fabrication of 3D popcorn-like Ag microstructures film array substrate: SERS and catalytic property

Qingyan Han,Yunxiang Li,Ye Chen,Shixing Fan,Yibin Hu,Ronghua Yan,Wei Gao,Chengyun Zhang,Wenwen Zhang,Jun Dong

Surface-enhanced Raman scattering (SERS) has tremendous significance in the fields of ultrasensitive detection and real-time in situ monitoring in catalysis. However, it remains a challenge to simultaneously achieve higher-quality SERS and excellent plasmonic catalytic properties in a nano/microstructure substrate under random excitation light. Here, we propose the design of a three-dimensional (3D) popcorn-like silver (Ag) microstructure (MS) with diameter of 1.2 ± 0.1 µm and a unique rough surface topography , realize a wide surface plasmon resonance (SPR) band ranging from 300 nm to 1100 nm, approximating a full spectrum. The popcorn-like Ag MSs with full-spectrum property effectively broaden the spectral overlap between the SPR band and wavelength of excitation light or absorption of probe molecules. Moreover, the 3D popcorn-like Ag MSs were used to construct a monolayer film array substrate on silicon wafer with a good homogeneity over large areas by an interfacial self-assembly method. The monolayer Ag MSs film array substrate can provide abundant “hot spots” and present excellent SERS performance for sensitive detection of Rhodamine 6G (Rh6G) with a low detection limit of 10 −9  M. The single-layer Ag MSs film array with superior SERS activity is utilized for in situ monitoring the plasmonic catalytic kinetics of 4-nitrothiophenol (4-NTP) dimerized into 4, 4′-dimercaptoazobenzene (DMAB) under 532 nm and 785 nm excitation, respectively. The mechanism on plasmonic catalytic reaction of the popcorn-like Ag MSs substrate is systemically investigated by experimental and theoretical simulations aspects. The Ag MSs film array substrate will offer a new strategy to further explore applications of SERS in sensors, photocatalysis , and bio/chemical analysis.

Efficient interfacial self-assembled MXene/Ag NPs film nanocarriers for SERS-traceable drug delivery

Chen Yi,Jiang Cailing,Huang Feixiang,Yu Zizhen,Jiang Li

Combining the unique advantages of two-dimensional transition metal carbon/nitrogen compounds (MXene) and the excellent surface-enhanced Raman scattering (SERS) performance of noble metal materials, MXene/Ag NPs films were proposed as nanocarriers for SERS-traceable drug delivery. The films were prepared by two-step self-assembly on positively charged silicon wafers using virtue of the high evaporation of ethyl acetate, the Marangoni effect, and an oil/water/oil three-phase system. With 4-mercaptobenzoic acid (4-MBA) as the probe molecule, the SERS detection limit was 10 −8  M and had shown a good linear relationship in the range of 10 −8 –10 −3  M. Simultaneously, the film had good uniformity, repeatability, and stability. When Ti 3 C 2 T x /Ag NPs films were used as nanocarriers, the anticancer drug doxorubicin (DOX) was loaded onto the surface through 4-MBA, and the tracking and monitoring were realized by SERS. The addition of glutathione (GSH) triggered the thiol exchange reaction, resulting in the shedding of 4-MBA from the surface of the film, which indirectly achieved the efficient release of DOX. Furthermore, the loading of DOX and the drug release effect triggered by GSH maintained a certain stability in serum, which provided a potential possibility for the subsequent loading and release of drugs by films with three-dimensional structures as scaffolds in biological therapy. Graphical abstract Self-assembled MXene/Ag NPs film nanocarriers for SERS-traceable drug delivery and GSH-triggered high-efficiency drug release

Fabrication and Sintering Behavior of Nano Cu–Ag Composite Paste for High-Power Device

Weishan Lv,Jiaxin Liu,Yun Mou,Yongjie Ding,Mingxiang Chen,Fulong Zhu

Silica Coated Upconversion Nanoplatform for Ag-Based Chemo-/Photodynamic Therapy against Drug-Resistant Bacteria

Yuxian Su,Yingyan Mao,Shen Wu,Li Liu,Shipeng Wen

Near-infrared (NIR) driven photodynamic therapy based on upconversion luminescent nanoparticles (UCNPs) is promising for fighting drug-resistant bacteria infections in deep tissues due to its good noninvasive, nonspecific, and non-drug-resistant properties, but is greatly limited by its low efficacy. Herein, honeycomb-silica-coated upconversion nanoparticles (UCNP@mSiO2) with a size of less than 100 nm were successfully prepared by a typical silica sol–gel reaction assisted with an expanding agent (p-xylene). The honeycomb silica shell has large pores with an average diameter of about 10 nm and large pore volume of 0.82 cm3/g and exhibits a MC540 loading as high as 9% in weight. The UCNP nanoparticle core can effectively capture NIR photons and activate the merocyanine 540 photosensitizer (MC540), generating reactive oxygen species to kill the drug-resistant bacteria of deep tissues. To avoid the drug prerelease, Ag nanoparticles in diameter close to that of the silica hole were covalently grafted onto the aminated UCNP@MC540@mSiO2 (UMS-NH2) nanoparticle. The Ag-decorated UMS-NH2 nanoparticles (UMSAg) showed synergistic antibacterial effects of Ag chemotherapy and photodynamic therapy and are more stable than undecorated UMS nanoparticles in an aqueous medium. The UMSAg with unreacted amino groups enhanced the binding of Ag to the bacterial membrane, effectively exerting the antibacterial effect of Ag+ and ROS. In in vitro antibacterial experiments, the killing rates of the UMSAg composite (150 μg/mL) against drug-resistant Staphylococcus aureus and drug-resistant Pseudomonas aeruginosa under NIR irradiation were 100% and 99.6%, respectively. In addition, the antibacterial activity of the UMSAg group was significantly higher than that of the sole Ag nanoparticles without irradiation. This work provides good insight for the design of efficient antibacterial agents and has a potential application for the bacterial infection of deep tissues.

Coordination-Driven One-Step Rapid Self-Assembly Synthesis of Dual-Functional Ag@Pt Nanozyme

Zaihui Du,Longjiao Zhu,Pengfei Wang,Xinyue Lan,Shenghao Lin,Wentao Xu

Realizing high-precise and adjustable regulation of engineering nanozyme is important in nanotechnology. Here, Ag@Pt nanozymes with excellent peroxidase-like and antibacterial effects are designed and synthesized by nucleic acid and metal ions coordination-driven one-step rapid self-assembly. The adjustable NA-Ag@Pt nanozyme is synthesized within 4 min using single-stranded nucleic acid as templates, and peroxidase-like enhancing FNA-Ag@Pt nanozyme is received by regulating functional nucleic acids (FNA) based on NA-Ag@Pt nanozyme. Both Ag@Pt nanozymes that are developed not only has simple and general synthesis approaches, but also can produce artificial precise adjustment and possess dual-functional. Moreover, when lead ion-specific aptamers as FNA are introduced to NA-Ag@Pt nanozyme, the Pb 2+ aptasensor is successfully constructed by increasing electron conversion efficiency and improving the specificity of nanozyme. In addition, both nanozyme has good antibacterial properties, with ~100% and ~85% antibacterial efficiency against Escherichia coli and Staphylococcus aureus , respectively. This work provides a synthesis method of novelty dual-functional Ag@Pt nanozymes and successful application in metal ions detection and antibacterial agents.

Increasing hotspots density for high-sensitivity SERS detection by assembling array of Ag nanocubes

Jiaqi Liu,Zhongshun Wang,Ya'nan Meng,Chunning Chen,Qiye Chen,Yalei Wang,Shuzhen Dou,Xiaoyang Liu,Nan Lu

Trace analysis has great promise in the fields of disease diagnosis and environment protection. Surface-enhanced Raman scattering (SERS) has wide range of utilization due to its reliable fingerprint detection. However, the sensitivity of SERS still needs to be enhanced. Raman scattering of target molecules around hotspots, the area with extremely strong electromagnetic field , can be highly amplified. Therefore, to increase the density of hotspots is one of the major approaches for enhancing the detection sensitivity of target molecules. In this paper, an ordered array of Ag nanocubes was assembled on a thiol modified silicon substrate as a SERS substrate, which provided high-density hotspots. The detection sensitivity is demonstrated by the limit of detection, which is down to 10 −6  nM with Rhodamine 6G as probe molecule. The wide linear range (10 −7 –10 −13  M) and low relative standard deviation (<6.48%) indicate the good reproducibility of the substrate. Furthermore, the substrate can be used for the detection of dye molecules in lake water. This method provides an approach for increasing hotspots of SERS substrate, which could be a promising method to achieve good reproducibility and high sensitivity.