查找使用阿拉丁产品的科研文献

Electrospinning of antibacterial and anti-inflammatory Ag@hesperidin core-shell nanoparticles into nanofibers used for promoting infected wound healing

Ren Xiuli,Hu Yanan,Chang Linna,Xu Shibo,Mei Xifan,Chen Zhenhua

Bacterial infection and excessive inflammation are still the main obstacles to wound repair. Thus, antibacterial and anti-inflammation nanomaterials are always attracting for infected wound healing. In this work, ultra-uniform (∼20 nm) and colloidally stable Ag nanoparticles (Ag-Hes NPs) with core-shell structure were prepared by using hesperidin as reducing and capping agent. The obtained Ag-Hes NPs present effective antibacterial properties on both Staphylococcus aureus and Escherichia coli. Ag-Hes NPs also got high 1,1-diphenyl-1-picrylhydrazyl scavenging capability of 69%. Under the package of polyvinyl alcohol and sodium alginate, Ag-Hes NPs were encapsulated into electro spun nanofibers to form hydrogel (Ag-Hes@H). This strategy provides a moisture environment which could enrich and release Ag-Hes NPs gradually. Cell experiments and animal wound healing investigation proved that Ag-Hes@H could promote the proliferation and migration of human umbilical vein endothelial cells and accelerate infected wound healing. Meanwhile, Ag-Hes@H significantly reduced the expression of inflammatory cytokines, including IL-6, MMP9 and TNF-α. Immunohistochemistry data further suggested that Ag-Hes@H accelerated wound closure by promoting collagen deposition and skin cell proliferation. The designed antibacterial and anti-inflammatory Ag-Hes@H has great potential for promoting infected wound healing.

Adhesive, Antibacterial, Conductive, Anti-UV, Self-Healing, and Tough Collagen-Based Hydrogels from a Pyrogallol-Ag Self-Catalysis System

Min Zhang,Qili Yang,Tianshuo Hu,Lele Tang,Yonghao Ni,Lihui Chen,Hui Wu,Liulian Huang,Cuicui Ding

Recently, versatile hydrogels with multifunctionality have been widely developed with emerging applications as wearable and implantable devices. In this work, we reported novel versatile hydrogels by self-catalyzing the gelation of an interpenetrating polymer network consisting of acrylic acid (AA) monomers and GA-modified collagen (GCOL) in situ decorated silver nanoparticles (AgNPs). The resultant hydrogel, namely AgNP@GCOL/PAA, has many desirable features, including good mechanical properties (such as 123 kPa, 916%, and 1961 J m−2 for the fracture stress, strain and tearing energy) that match with those of animal skin, excellent self-healing performance, favorable conductivity and strain sensitivity as a flexible biosensor, and excellent antibacterial and anti-UV properties, as well as the strong adhesiveness on skin. Moreover, AgNP@GCOL/PAA showed excellent biocompatibility via in vitro cell culture. Remarkably, AgNP@GCOL/PAA displayed superior hemostatic properties with sharply decreasing blood loss for a mouse liver incision, closely related to its strong self-adhesion which produced anchoring strength to the bleeding site and thus formed a network barrier with liver tissue. This study provides new opportunities for the facile preparation of widely used multifunctional collagen-based hydrogels based on a simple pyrogallol-Ag system.

High Flux and Antifouling Nanofiltration Membrane Modified by Ag@UiO-66-NH2 and Its Application for Biphenol A Removal

Qing-Chun Chen,Yu Bang,Lu Li,Hui-Yu Deng

Owing to the specific porous structure which could provide additional passage channel for some molecules, metal organic frameworks are attractive candidates for enhancing permeability and selectivity of membranes in pervaporation, reverse osmosis, and gas separation. In this experiment, Ag@UiO-66-NH2 was introduced into polyamide separation layer by interfacial polymerization of triethylenetetramine and 1,3,5-benzenetricarboxylic acid chloride for nanofiltration. The results indicated that Ag@UiO-66-NH2 nanoparticles did endow the membranes with rapid diffusion pathways for water molecules. When the content of Ag@UiO-66-NH2 was 0.03 g, the prepared membrane (NF-Ag-3) showed high flux about 47.3 L·m-2·h-1 at 0.6 MPa, which is about 2-fold higher than that of polyamide membrane without Ag@UiO-66-NH2, while the MgSO4 rejection rate remained about 87.4%. The membrane also showed excellent antifouling properties, and the water flux recovery ratio was 95.6% after filtration BSA solution. When it was applied for 50 mg/L bisphenol A removal, the rejection rate reached 94.6%, and the flux is about 49.1 L·m-2·h-1. Moreover, Ag particles on UiO-66-NH2 rendered the membrane with good inhibition for Escherichia coli. The antibacterial rate of the membranes is above 95% when the loading of Ag@UiO-66-NH2 is more than 0.03 g.

In situ SERS monitoring of intracellular H2O2 in single living cells based on label-free bifunctional Fe3O4@Ag nanoparticles

Yue Wang,Cheng Cheng,Ruofei Ma,Zhangrun Xu,Yukihiro Ozaki

Visualization of signaling molecules in single living cells is crucial for understanding cellular metabolism and physiology, which can provide valuable insights into early diagnoses and treatments of diseases. Highly sensitive in situ monitoring of intracellular analytes released from single living cells by virtue of label-free nanosensors is urgently needed, which can avoid interferences from molecular labeling. Here, we proposed an ultrasensitive strategy for in situ imaging of intracellular H2O2 in single living cancer cells by surface-enhanced Raman scattering (SERS) spectroscopy with the utilization of label-free Fe3O4@Ag core–satellite nanoparticles (NPs). The Fe3O4@Ag NPs can efficiently and selectively catalyze the oxidation of the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2. Additionally, they exhibit excellent SERS activity that allows for in situ monitoring of intracellular H2O2 in living cells through establishing the correlation between the H2O2 level and the SERS intensity of the catalytic oxidation product of TMB. The H2O2 concentration is revealed through the SERS intensity of oxidized TMB with a good linear response in a wide range from 1 fM to 1 mM. Moreover, the intracellular H2O2 level in live cancer cells and imaging of the distribution of H2O2 inside single cells can be achieved by using such a label-free nanosensor based strategy. Our work demonstrates that the label-free Fe3O4@Ag NP-based SERS imaging and quantification strategy is a promising and powerful approach to assess intracellular H2O2 in living cells and allows us to monitor single-cell signaling molecules with nanoscale resolution.

MoS2@PDA@Ag/PVA Hybrid Hydrogel with Excellent Light-Responsive Antibacterial Activity and Enhanced Mechanical Properties for Wound Dressing

Pengfei Yan,Mengya Li,Jie Liu,Yadi Hu,Keyong Tang

Hydrogel is an ideal wound dressing material because of its 3D network structure, which is similar to that of the extracellular matrix. However, it is a challenge to design antibiotic-free hydrogels with both antibacterial activity and enhanced mechanical strength. In this study, a polyvinyl alcohol (PVA) hybrid hydrogel incorporated with molybdenum disulfide@polydopamine@silver (MoS 2 @PDA@Ag) is prepared for rapid killing of bacteria under irradiation with near-infrared (NIR) light. The interpenetration of MoS 2 -based nanoparticles and PVA molecular chain significantly improves the mechanical property of the hydrogel. The hydrogels demonstrate an excellent photothermal effect and antibacterial activity, and the photocatalytic properties are considerably enhanced by Ag doping. The hydrogel exhibits favorable antibacterial activity after irradiation with 808 nm NIR light for 15 min due to the synergistic effect of reactive oxygen species and hyperthermia. Meanwhile, in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay further demonstrated that all hydrogels are nontoxic when their effects are examined against mouse fibroblasts ( L929 ) cells. In addition, the MoS 2 @PDA@Ag/PVA hydrogel can promote wound healing compared with the pure PVA hydrogel, demonstrating its significant potential in mitigating bacterial infection of wounds.

Boosting Antibacterial Photodynamic Therapy in a Nanosized Zr MOF by the Combination of Ag NP Encapsulation and Porphyrin Doping

Bao-Xuan Xie,Hai-Shuang Wang,Hui-Qian Zheng,Jin Xu,Li Chen,Fang-Zhong Zhang,Yu-Lin Wang,Zu-Jin Lin,Rong-Guang Lin

Antibacterial photodynamic therapy (aPDT) is regarded as one of the most promising antibacterial therapies due to its nonresistance, noninvasion, and rapid sterilization. However, the development of antibacterial materials with high aPDT efficacy is still a long-standing challenge. Herein, we develop an effective antibacterial photodynamic composite UiO-66-(SH)2@TCPP@AgNPs by Ag encapsulation and 4,4′,4″,4‴-(porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid) (TCPP) dopant. Through a mix-and-match strategy in the self-assembly process, 2,5-dimercaptoterephthalic acid containing –SH groups and TCPP were uniformly decorated into the UiO-66-type framework to form UiO-66-(SH)2@TCPP. After Ag(I) impregnation and in situ UV light reduction, Ag NPs were formed and encapsulated into UiO-66-(SH)2@TCPP to get UiO-66-(SH)2@TCPP@AgNPs. In the resulting composite, both Ag NPs and TCPP can effectively enhance the visible light absorption, largely boosting the generation efficiency of reactive oxygen species. Notably, the nanoscale size enables it to effectively contact and be endocytosed into bacteria. Consequently, UiO-66-(SH)2@TCPP@AgNPs show a very high aPDT efficacy against Gram-negative and Gram-positive bacteria as well as drug-resistant bacteria (MRSA). Furthermore, the Ag NPs were firmly anchored at the framework by the high density of –SH moieties, avoiding the cytotoxicity caused by the leakage of Ag NPs. By in vitro experiments, UiO-66-(SH)2@TCPP@AgNPs show a very high antibacterial activity and good biocompatibility as well as the potentiality to promote cell proliferation.

Novel Cu@Ag Micro/Nanoparticle Hybrid Paste and Its Rapid Sintering Technique via Electromagnetic Induction for High-Power Electronics

Zhuohuan Wu,Wei Liu,Jiayun Feng,Zhicheng Wen,Xinyue Zhang,Xinming Wang,Chunqing Wang,Yanhong Tian

Due to the harsh working environments up to 600 °C, the exploration of high-temperature interconnection materials is significantly important for high-power devices. In this study, a hybrid paste including Cu@Ag core–shell microparticles (MPs) and Ag nanoparticles (NPs) was designed to achieve Cu–Cu bonding. The Cu@Ag MPs exhibited excellent oxidation stability in an air atmosphere with the Ag layer coating on the Cu core. Ag NPs fill the pores among the Cu@Ag MPs and reduce the sintering temperature of the hybrid paste. The Cu–hybrid paste–Cu joints were formed via electromagnetic induction heating within approximately 15 s. When sintered at 26 kW, the shear strength of the joint reached 48 MPa, the porosity decreased to 0.73%, and the resistivity was down to 13.25 μΩ·cm. Furthermore, a possible interconnection mechanism at the contact interface between the Cu substrate and the sintered hybrid paste was proposed, which is related to the melting point of metal particles and the effect of magnetic eddy currents. This fast bonding technology inspires a new approach to interconnection for high-power devices under high operation temperatures.

Spontaneous Redox-Reaction-Driven Growth of Ag Nanoparticles on Co(OH)2 Nanoflower Arrays for Surface-Enhanced Raman Scattering

Tingting Fan,Li Cai,Zhulin Huang,Haibin Tang,Lijun Zhang,Zhongbo Li

A simple and reliable method is developed to fabricate Ag-nanoparticle-decorated Co(OH)2 nanoflowers grafted on polyacrylonitrile (PAN) nanopillar arrays as uniform and sensitive surface-enhanced Raman scattering (SERS) substrates. First, Co(OH)2-nanosheet-assembled nanoflowers are achieved on the highly uniform PAN nanopillar arrays via electrochemical deposition. Then, Ag nanoparticles (Ag-NPs) are decorated onto the Au-nanoparticle-precoated Co(OH)2 nanoflowers based on a spontaneous redox reaction (SRR) between the silver ions and Co(OH)2 nanosheets at room temperature. Ag-NPs can be successfully in situ synthesized on the Co(OH)2 nanoflowers, and Au nanoparticles precoated on the surface of the Co(OH)2 nanosheets can ensure that the Co(OH)2 nanoflower structure does not collapse. Because of the highly uniform PAN nanopillar arrays and the high-density sub-10 nm gaps between the neighboring Ag-NPs on the surface of the Co(OH)2 nanoflowers, the hierarchical three-dimensional Ag@Co(OH)x grown on PAN nanopillar arrays can produce a reproducible and sensitive SERS effect. To verify the SERS performance of the substrate, 4-aminothiophenol (4-ATP) is used as the probe molecule, and the Ag@Co(OH)x grown on PAN nanopillar arrays is employed as the SERS substrate. As a result, 4-ATP concentrations as low as 10–10 M can still be identified, exhibiting high SERS activity. Additionally, the relative standard deviation value of the main characteristic peak of 10–5 M 4-ATP is 9.43%, indicating good uniformity of the SERS signal of the substrate. The SRR between silver ions and Co(OH)2 can provide a simple route to prepare heterostructures as SERS substrates, which has great potential for application in the field of analysis.

11-MUA/Ag Modified Large-Core Fiber-Optic SPR Sensing Probe and Its Highly Sensitive Detection for Rabies Virus

Juan He,Qian Liao,Wenlin Feng

The Fabrication and SERS Performance of Multi-layer Hollow Au-Ag Alloy Nano Urchins Structure-based SERS Fiber Probe

Hao Zhenbang,Tian Qihang,Cao Shiyi,Han Xiaoyu,Zhang Jihong,Xie Jun,Zhao Xiujian

Novel hollow Au Ag alloy nano urchins were synthesized via Ag seeds growth method, and self-assembly coated on the wall and end-tip of silica fiber for fiber probe fabrication. The nano urchins homogeneously distributed on fiber surface because of fiber silanization. The sizes and tip sharpness of the nano-urchins could be controlled by Ag seeds. The elements distribution analysis indicated there was high Ag content in tip-top for better surface enhance Raman scattering performance. The detectable concentration could be as low as 10 −8 M using crystal violet molecules as analyte. Moreover, the fiber probes were stable in air, due to Au in the alloy. This fiber probe could be used for low content single molecular analysis.

Construction of ratiometric fluorescent nanosensors based on carbon dots dual emission strategy for high-sensitivity visual detection of Ag+

Junfang Chang,Jie Mao,Yifei Lu,Yalei Liu,Sui Wang

Water-soluble purple fluorescent carbon nanodots (P-CDs) were synthesised using 2-phenylphenol, and red fluorescent carbon dots (R-CDs) were prepared from o-phenylenediamine and phosphoric acid. Based on the fluorescence quenching effect of Ag+ on carbon quantum dots, and additionally introducing a red light-emitting quantum dot with excellent performance and high quantum yield, a dual emission ratiometric fluorescent nanosensor (P-CDs/R-CDs) was established. The semi-quantitative detection of silver ions can be realised. Under the excitation light of 254 nm and 365 nm, the fluorescence spectrum shows double emission fluorescence peaks at 343 nm and 626 nm, which originate from the fluorescence emission of the synthesised C-dots and the additionally introduced C-dots, respectively. The relationship between the ratio of the intensity of the two emission peaks F343/F626 and the concentration of silver ions realises the analysis and detection of silver ions. The linear detection range of this method was 0.096–10 μM, and the detection limit (LOD, S/N = 3) was 32 nM. In addition, the method can also perform naked-eye visual detection according to the fluorescence colour change of the probe under ultraviolet light, and realise the rapid monitoring of Ag+ on site. The P-CDs/R-CDs ratiometric fluorescence sensor provides a new method for the detection of Ag+ and promotes the development of heavy metal ion sensing.

Amino acid-mediated loading of Ag NPs and tannic acid onto cotton fabrics: Increased antibacterial activity and decreased cytotoxicity

Yang Wu,Sheng Yang,Feiya Fu,Jingjing Zhang,Jianhua Li,Tingfang Ma,Xiangdong Liu,Juming Yao

In this paper, L-cysteine (Cys) is firstly bonded to the surface of cotton non-woven (CO) fabric as esterification. In this way, Ag + and tannic acid (TA) are adsorbed onto the modified fabric via complexation and hydrogen bond interaction. After a sustainable one-step redox reaction, a Cys modified CO fabric decorated with Ag NPs and TA (CO-Cys-Ag-TA) is prepared. Because of the stabilizing effect of Cys and TA, the synthesized Ag NPs with a mean size of 88.9 nm are uniformly distributed on the modified fabric surface. Through the comparative test, it has been revealed that the antibacterial activity of Ag NPs is improved after loading TA, and the loading of Ag NPs significantly reduces the cytotoxicity of TA. In this context, the bacteriostatic reduction rate of CO-Cys-Ag-TA against S. aureus and E. coli is close to 100%, and its antibacterial activities are greater than 98.5% after 50 washing cycles. Meanwhile, its cell viability value reaches up to 88.0% with the presence of 0.1 mg/mL to 0.8 mg/mL CO-Cys-Ag-TA.