载铜锌纳米羟基磷灰石的抗菌性能及机理研究

在常压下合成了纳米羟基磷灰石（n—HA）浆料，并在水介质中制备了载铜、载锌和载铜锌双离子n—HA抗菌材料．运用原子吸收光谱（AAS）、转靶X射线衍射（XRD）、透射电镜（TEM）等手段对材料的理化性能进行了表征．并对该抗菌材料的抗菌性能进行了研究．结果表明，载铜和载铜锌双离子n—HA抗菌材料对革兰氏阴性菌E．coil和革兰氏阳性菌S．aureus均有较强的抑制和杀灭作用，而载锌n—HA的抗菌能力较弱．本文还通过实验探讨了该抗菌材料的抗菌机理．     

溶胶-凝胶法合成ZnO纳米材料及其抗菌性能研究

采用溶胶-凝胶法制备氧化锌纳米材料并考察了其抗菌性能.研究发现,通过调控醋酸锌-无水乙醇-氢氧化钠反应体系的反应温度、反应时间、反应物浓度以及反应体系中的水含量可以控制纳米ZnO的粒径分布;以金黄色葡萄球菌和大肠杆菌作为革兰氏阳性菌和革兰氏阴性菌的代表,用抑菌圈法考察了材料的抗菌性能,结果表明,溶胶-凝胶法合成的ZnO纳米材料抑菌效果明显优于相应的水热法产物和市售产品,且与其粒径分布密切相关;在实验条件下,ZnO材料对大肠杆菌和金黄色葡萄球菌的抑制性能随ZnO纳米材料的粒径增大在5nm左右出现一个极值,材料的粒径小于或大于5nm,其抗菌效果均变差.     

碳纳米管镀铜薄膜的抗菌性研究

本文用离子束辅助沉积（mAD）方法在碳纳米管薄膜表面制备铜薄膜。用琼脂平板法测试了抗菌率，测试菌种为革兰氏阴性大肠杆菌（E．coil）和革兰氏阳性金黄色葡萄球菌（S．aureus）；用扫描电子显微镜（SEM）观测了镀铜碳纳米管薄膜的微观形貌；用能量散射X射线谱（EDX）分析了镀铜碳纳米管薄膜表面元素的原子百分比；用X射线光电子能谱（XPS）分析了镀铜碳纳米管薄膜的表面元素的价态。研究结果表明，镀铜膜碳纳米管薄膜具有优良的抗菌性能，且比在热解碳上镀铜膜样品的抗菌性强。     

以γ-氯丙基三甲氧基硅烷作活化剂共价修饰季胺盐的纳米SiO2粉体的抗菌性的研究

在纳米SiOx表面通过先接枝高分子聚乙烯亚胺（PEI）长链,再用卤代烷烷基化成高分子季铵盐,制得一种新型的纳米SiQ粉体。抗菌实验表明,采用此工艺制得的纳米SiOx粉体对革兰氏阳性菌、革兰氏阴性菌、酵母菌和霉菌均有较好的抗菌性。对细菌的临界抗菌浓度为1．0mg／ml。热处理和洗涤实验表明抗菌纳米SiOx具有良好的耐热性能和稳定性。     

卷材用聚氨酯抗菌涂料的研制

为了研制合适的、具有优异抗菌性能的卷材用涂料/涂层,根据颜料体积浓度(PVC)、临界颜料体积浓度(CPVC)对卷材涂料耐腐蚀性、附着力等性能的影响,结合卷材涂料黏度、固含量等性能指标,选取合适的材料,设计并研制了聚氨酯抗菌涂料与涂层.大肠杆菌试验表明,该涂层在抗菌剂含量质量分数为0.5%时,抗菌率达99.9%,具有优异的抗菌性能.涂料、涂层的基本性能测试表明,各项性能均符合要求.     

银离子注入热解碳的抗菌性研究

本文用革兰氏阳性菌-金黄色葡萄球菌和革兰氏阴性菌-大肠杆菌研究了注银医用热解碳的抗菌性。注入银离子的能量为70 keV,剂量分别为5×1014、1×10155、×1015、1×1016、5×1016ions/cm2。用卢瑟福背散射分析(RBS)和X射线光电子能谱(XPS)对注银热解碳的表面进行了微观分析。抗菌实验结果表明,样品的抗菌率随着注入剂量的增大而增大,当注入剂量高于1×1016ions/cm2时,注银热解碳对金黄色葡萄球菌和大肠杆菌的抗菌率接近100%。RBS和XPS分析结果表明,银离子注入到热解碳表层,且浓度随注入剂量的增大而增加,富银的表面层起到抑菌和杀菌作用。     

抗菌涂料、油漆

日常生活中,涂料和油漆是家具生产、居室装修必不可少的材料。涂料和油漆发展的一个方向是抗菌涂料、油漆。所谓抗菌,是指在一定时间内抑制细菌的生长和繁殖。抗菌涂料、油漆是在油漆、涂料中加入抗菌剂,使涂料、油漆具有抗菌的功能。工程塑料国家工程研究中心生产的抗菌剂具有抗菌效率高、抗菌时间长、抗菌谱广、添加量少、价格合理等特点。添加１％～１－５％的抗菌剂,即可使涂料、油漆对金黄色葡萄球菌、大肠杆菌等葛兰氏细菌的抑菌率达９９％以上,对霉菌及真菌的生长也有明显的抑制作用。抗菌剂对人体无毒无害,也不会影响涂料原有…     

壳聚糖季铵盐/有机累托石纳米复合材料的抗菌性能研究

合成了壳聚糖季铵盐, 并通过溶液插层法将其插层进入有机累托石层间制备纳米复合材料, 研究表明, 当壳聚糖季铵盐与有机累托石的质量比为2∶1时, 其获得了4.8nm的最大层间距. 抗菌结果显示, 在偏酸、中性及偏碱性条件下, 所有的纳米复合材料都具有较好的抗菌性能, 且与有机累托石的含量和层间距成正比. 与壳聚糖季铵盐及有机累托石相比, 纳米复合材料对革兰氏阳性菌、革兰氏阴性菌及真菌的抗菌性能大大提高, 对金黄色葡萄球菌和枯草芽孢杆菌的最小抑制浓度仅为0.00313% (W/V), 且能在30min内杀死90%以上的金黄色葡萄球菌, 80%以上的大肠杆菌. 最后, 通过TEM和SEM结果探讨了其抗菌机理.     

纳米ZnO的抗菌性能研究

纳米ZnO是一种常见的光学材料,将其与其他材料复配可以制得抗菌性能良好的包装材料。根据GB/T 21510—2008《纳米无机材料抗菌性能检测方法》,以大肠杆菌和金黄色葡萄球菌为测试菌种,以SiO2为对照试验,测试了纳米ZnO对大肠杆菌和金黄色葡萄球菌的抗菌性能;同时,采用抑菌圈法对其抗菌性能进行了定性研究。结果表明：纳米ZnO对大肠杆菌和金黄色葡萄球菌具有良好的抑菌性能,且初步测定了纳米ZnO对这两种菌的最小抑菌浓度,分别为0.312 5%和0.625%;纳米ZnO对大肠杆菌和金黄色葡萄球菌高度敏感,纳米ZnO对二者的抑菌圈直径都大于15 mm。     

可用于正压防护服的抗菌聚氨酯复合面料研究

采用国内外标准推荐方法检测抗菌聚氨酯复合面料的物理性能、防护性能、耐洗消性能和抗菌性能。结果表明,抗菌聚氨酯复合面料各项物理性能指标和耐微生物液体穿透性能均达到国内外相关标准规定的要求,材料洗消后各项指标无明显变化,对革兰氏阳性菌和阴性菌抑菌率在99%以上。聚氨酯双面贴膜复合面料各项性能指标均达到正压防护服要求,且具有优良的耐洗消性和抗菌性,柔韧轻便,适合用于研制正压防护服等生物防护装备。     

Diameter of titanium nanotubes influences anti-bacterial efficacy

Bacterial infection of in-dwelling medical devices is a growing problem that cannot be treated by traditional antibiotics due to the increasing prevalence of antimicrobial resistance and biofilm formation. Here, due to changes in surface parameters, it is proposed that bacterial adhesion can be prevented through nanosurface modifications of the medical device alone. Toward this goal, titanium was created to possess nanotubular surface topographies of highly controlled diameters of 20, 40, 60, or 80 nm, sometimes followed by heat treatment to control chemistry and crystallinity, through a novel anodization process. For the first time it was found that through the control of Ti surface parameters including chemistry, crystallinity, nanotube size, and hydrophilicity, significantly changed responses of both Staphylococcus epidermidis and Staphylococcus aureus (pathogens relevant for orthopaedic and other medical device related infections) were measured. Specifically, heat treatment of 80 nm diameter titanium tubes produced the most robust antimicrobial effect of all surface treatment parameters tested. This study provides the first step toward understanding the surface properties of nano-structured titanium that improve tissue growth (as has been previously observed with nanotubular titanium), while simultaneously reducing infection without the use of pharmaceutical drugs.     

In vitro anti-bacterial and cytotoxic properties of silver-containing poly(L-lactide-co-glycolide) nanofibrous scaffolds

Electrospinning has recently emerged as a leading technique for the formation of nanofibrous structures made of organic and inorganic components. In this study, nanofibrous scaffolds were prepared by electrospining a bend solution of poly(L-lactide-co-glycolide) (PLGA) and silver nanoparticles in 1,1,1,3,3,3,-hexafluoro-2-propanol (HFIP). The resulting fibers ranged from 420 to 590 nm in diameter. To evaluate the possibility of using silver-containing PLGA as a tissue engineering scaffold, experiments on cell viability and antibacterial activity were carried out. As a result, PLGA nanofibrous scaffolds having silver nanoparticles of more than 0.5 wt% showed antibacterial effect against Staphylococcus aureus and Klebsiella pneumonia. Furthermore, silver-containing PLGA nanofibrous scaffolds showed viability, indicating their possible application in the field of tissue engineering.     

Comparison of the anti-bacterial activity on the nanosilver shapes: Nanoparticles,nanorods and nanoplates

In this study, we comparison of the antimicrobial activity on the nanosilver shapes; Ag-nanoplates (Ag-NPls), Ag-nanorods (Ag-NRds) and Ag-nanoparticles (Ag-NPs). Nanosilver shapes were prepared with a stabilizer, such as poly (N-vinyl-2-pyrrolidone) (PVP). Antimicrobial effect of nanosilver shapes for Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was investigated using disc diffusion and minimum inhibitory concentration (MIC) methods. The growth of Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria were inhibited by nanosilver shapes. With BET technique, it was found that surface area of nanosilver shapes are key factor for controlling antimicrobial activity inside of the S. aureus and E. coli bacteria. Anti-bacterial activity of nanosilver shapes was found to be dependent on the shape and size of silver particles. Also, the Ag-NPls did show the best surface area and antimicrobial activity for the test organisms. The scanning electron microscopy (SEM), indicated that, the most strains of S. aureus and E. coli were damaged and extensively disappeared by addition of Ag-NPls.     

Synthesis, optical, thermal and anti-bacterial activities of semiorganic material-thiosemicarbazide cadmium(II) picrate

Semiorganic material of thiosemicarbazide cadmium(II) picrate (TSCPACd) was synthesized. Conductivity measurement was performed using conductivity meter in dimethyl sulfoxide (DMSO) (0.01 g/100 ml). TSCPACd crystallizes in the triclinic space group P-1. FTIR study was carried out in order to confirm the presence of functional groups. UV-vis-NIR spectral studies show that the crystal is transparent in the wavelength range 375-1100 nm. Thermogravimetric and differential thermal analyses reveal the thermal stability of the crystal. The anti-bacterial and anti-fungal activities of the title compound were performed by disk diffusion method against the standard bacteria E. coli, K. pneumonia, and E. faecalis and against the fungus S. aureus, Aspergillus niger and Aspergillus flavus. The compound exhibits good anti-fungal activity.     

Synthesis and anti-bacterial activity of Cu, Ag and Cu-Ag alloy nanoparticles: A green approach

Metallic and bimetallic nanoparticles of copper and silver in various proportions were prepared by microwave assisted chemical reduction in aqueous medium using the biopolymer, starch as a stabilizing agent. Ascorbic acid was used as the reducing agent. The silver and copper nanoparticles exhibited surface plasmon absorption resonance maxima (SPR) at 416 and 584 nm, respectively; while SPR for the Cu-Ag alloys appeared in between depending on the alloy composition. The SPR maxima for bimetallic nanoparticles changes linearly with increasing copper content in the alloy. Transmission electron micrograph (TEM) showed monodispersed particles in the range of 20 ± 5 nm size. Both silver and copper nanoparticles exhibited emission band at 485 and 645 nm, respectively. The starch-stabilized nanoparticles exhibited interesting antibacterial activity with both gram positive and gram negative bacteria at micromolar concentrations.     

Green synthesis of silver nanoparticles using hypericin-rich shoot cultures of Hypericum hookerianum and evaluation of anti-bacterial activities

The paper reports a green chemistry approach for the synthesis of silver nanoparticles (AgNPs) using hypericin-rich shoot cultures of Hypericum hookerianum as reducing agent. Normal green shoot cultures deficient in hypericin and red-pigmented shoot cultures rich in hypericin (3.01% DW) were raised in Murashige and Skoog nutrient medium containing 1.0 mg/L kinetin (KIN) and 0.2 mg/L naphthaleneacetic acid (NAA), respectively. Dried powder extracts of whole shoots were used for AgNPs formation. The effect of temperature on the formation of AgNPs is investigated. The nanoparticles obtained were characterised using UV–Vis spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD) analyses. The UV–Vis spectra of AgNPs gave surface plasmon resonance (SPR) at 440 nm. The synthesised AgNPs were effective against different multidrug-resistant human pathogens such as Bacillus subtillis (Gram positive) and Pseudomonas aeruginosa (Gram negative) species. Further, the effect of hypericin concentration on anti-bacterial activity was investigated and was found to increase with increase in concentration.     

Graphene oxide-silver/cotton fiber fabric with anti-bacterial and anti-UV properties for wearable gas sensors

Wearable gas sensors can improve early warning provision for workers in special worksites and can also be used as flexible electronic platforms. Here, the flexible multifunctional gas sensor was prepared by grafting graphene oxide (GO)-Ag onto cotton fabric after swelling. The maximum bacterial inhibition rate of GO-150/cotton fabric was 95.6% for E. coli and 87.6% for S. aureus, while retaining the original high moisture permeability of cotton fabric. So GO/cotton fabric can resist the multiplication of bacteria. At the same time, GO can greatly improve the UV protection performance of cotton fabric used in garments. With increase of the GO concentration, the UV protection ability of composite fabric is enhanced. Finally, GO-Ag/cotton fabric sensors had stable NH₃ gas-sensitive properties and good washing stability. In conclusion, these cotton fabric sensors with antibacterial properties, UV resistance and highly sensitive gas-sensitive properties have potential applications in wearable early warning devices and textile products.     

Rosmarinus officinalis directed palladium nanoparticle synthesis: Investigation of potential anti-bacterial,anti-fungal and Mizoroki-Heck catalytic activities

The present work was aimed to account a green and eco-friendly synthesis of palladium nanoparticles using Rosmarinus officinalis leaves extracts for the first time, therefore, that can be an acceptable replacement for chemical media to improve potential biological properties. The synthesized palladium nanoparticles were fully characterized using FT-IR, XRD, FESEM, TEM and UV/Vis spectroscopy techniques. Catalytic activity was investigated by Mizoroki-Heck reaction, and optimized based on solvent, temperature and time of the reaction, and the best results were found in water as a green media without any additional reagents. Biological activity of the synthesized nanoparticles were evaluated in terms of antibacterial and anti-fungal assessments against Staphylococcus aureus, Staphylococcus epidermidis, E. coli, and Micrococcus lutens bacteria’s and Candida parapsilolis, Candida albicans, Candida glabrata and Candida krusei fungus. Based on our knowledge, this is a comprehensive and first study on the catalytic and biological activity of palladium nanoparticles synthesizing from Rosmarinus officinalis, which presents great and significant results (in both catalytic and biological activities) based on a simple and green procedure.     

Repositing honey incorporated electrospun nanofiber membranes to provide anti-oxidant,anti-bacterial and anti-inflammatory microenvironment for wound regeneration

Topical application of honey for tissue regeneration, has recently regained attention in clinical practice with controlled studies affirming its efficacy and indicating its role in regeneration over repair. Parallely, to overcome difficulties of applying raw honey, several product development studies like nanofibrous matrices have been reported. However, one approach concentrated on achieving highest possible honey loading in the nanofiber membranes while other studies have found that only specific honey dilutions result in differential cellular responses on wound healing and re-epithelization. From these results, it can be suggested that high honey loading provides optimum external microenvironment, low-loaded membranes could provide a more conducive internal microenvironment for tissue regeneration. With this hypothesis, this paper sought to evaluate ability of low-honey loaded nanofibers to modulate the anti-oxidant, anti-biofilm and anti-inflammatory properties which are important to be maintained in wound micro-environment. A loading-dependent reduction of biofilm formation and anti-oxidant activity was noted in different concentration ranges investigated. After scratch assay, a certain honey loading (0.5%) afforded the maximum re-epithelization. Since there is lack of methods to determine anti-inflammatory properties of nanofiber membranes during epithelial healing process, we performed anti-inflammatory assessment of nano-fibers by evaluating the expressions of pro-inflammatory markers-Cycloxygenase-2 (COX-2) and Interleukin-6 (IL-6) and to confirm the optimized concentration. Considering the role of COX-2 and IL-6, the novel methodology used in this study can also be developed as an assay for anti-inflammatory matrices for wound healing.

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The influence of operating parameters on the drug release and anti-bacterial performances of alginate wound dressings prepared by three-dimensional plotting

Three-dimensional plotting was used to manufacture fibrous alginate hydrogel wound dressings. Samples manufactured using varied operating parameters (increased air pressure, nozzle diameter, and layer increment or decreased calcium concentration, alginate concentration, and speed of the nozzle in the x and y directions) were compared to the control samples. The changes in the fiber size, porosity, tensile properties, degradation, swelling ratio, tetracycline release efficacy, water vapor transmission rate (WVTR), and bacterial inhibition potential due to alterations of the operating parameters were measured. The samples manufactured using altered operating parameters had larger fiber sizes and were less porous than the controls (p < 0.05). A significantly higher Young's modulus, a larger ultimate tensile strength, less degradation, and lower swelling ratios were also found among some of the altered samples (p < 0.05). The tetracycline release efficacies and bacterial inhibition potentials of the altered samples were not found to be significantly different from those of the controls. The WVTRs of most samples were slightly lower than those of common commercial dressings. When compared to films, the fibrous samples were able to absorb liquid faster and were less stiff, allowing for better conformation to the contours of the wounds. The fibrous samples also provided more sustained tetracycline release.