新型湿法纳米银制备技术及其毒性行为

针对目前纳米银(AgNPs)制备方法中存在的纳米银颗粒粒度分布不均,稳定性较差的问题,利用柠檬酸钠和无水乙醇作还原剂,以柠檬酸钠和聚乙烯吡咯烷酮(PVP)作为保护剂制备纳米银.利用紫外吸收光谱分析、XRD、SEM、TEM、EDS、Zeta电位仪等多种技术表征所制备纳米银的特征,结果表明纳米银颗粒为球形面心立方结构,粒径...     

纳米银粉在水溶液中的分散及粒径表征

利用直流电弧等离子体蒸发冷凝法制备纳米银粉,采用X射线衍射分析对纳米银粉的结构进行表征,采用纳米激光粒度仪研究不同超声分散工艺与不同离子类型的分散剂聚乙烯吡咯烷酮、十六烷基三甲基溴化氨、十二烷基硫酸钠对纳米银粉在水溶液中分散性能的影响,获得纳米银粉的最佳分散工艺与激光粒径分布,对比研究纳米银粉的激光粒径与透射电镜统计的粒径的差异。结果表明:纳米银颗粒为立方晶系多晶体,颗粒的结晶性良好;以十六烷基三甲基溴化氨为分散剂的效果最理想,最佳超声波功率为600 W;当十六烷基三甲基溴化氨的质量浓度为0.5 g/L时,纳米银颗粒的分散稳定性较好;激光粒径反映的纳米颗粒的动态二次粒径略大于从透射电镜图像统计得到的粒径。     

利用南瓜蒸煮液绿色制备纳米银及其抑菌性能的研究

目的 以南瓜蒸煮液和AgNO3为原料,烷基糖苷(APG)为表面活性剂,以微波加热绿色制备纳米银溶胶,研究其制备工艺、性能和抑菌效果。方法 以单因子对纳米银的制备进行优化。通过紫外-可见吸收光谱(UV-vis)、透射电镜(TEM)、能量色谱(EDS)和X射线衍射(XRD)等方法对合成纳米银的特征吸收峰、形貌以及稳定性等进行分析,并考察纳米银对大肠杆菌(E.coli)和金黄色葡萄球菌(S.aureus)的抑菌性能。结果 纳米银制备适宜的优化工艺条件:在南瓜蒸煮液体积为40 mL情况下,AgNO3的初始质量浓度为1.2 g/L、pH值为13、微波加热时间为60 s。经优化后,所制备的纳米银的UV-vis光谱在406 nm处出现强的特征吸收峰,EDS色谱进一步证实了纳米银的存在。纳米银为球形,平均粒径为13.4 nm,粒径小,分散性和稳定性好。抗菌试验表明,不同质量浓度的纳米银对E.coli和S.aureus均有较强的抑制和杀灭效果,对E.coli的MIC值和MBC值分别为5 mg/L和10 mg/L,对S.aureus的MIC值和MBC值分别为40 mg/L和320 mg/L。结论 该AgNPs对革兰氏阴性和革兰氏阳性细菌具有抗菌能力,在食品包装中具有较好的应用前景。     

Ag/PVA/SiW_(12)复合材料的制备及光催化活性

应用静电纺丝技术和热处理方法制备了疏水性聚乙烯醇/硅钨酸(PVA/SiW_(12)),随后利用光还原反应使银纳米粒子(AgNPs)沉积在PVA/SiW_(12)纤维上的三元复合纳米材料上。采用XPS、FT-IR和UV-Vis鉴定了掺杂材料的组成和结构。场发射扫描电镜和透射电镜显示,AgNPs的直径大小约为25nm。光催化性质结果表明,制备的Ag/PVA/SiW_(12)三元复合纳米材料与没有AgNPs存在的材料相比,具有优越的光催化活性。     

膨润土载纳米银抗菌剂的制备及性能研究

本文将硝酸银溶液与酸改性膨润土进行离子交换反应,膨润土做模板,十二烷基苯磺酸钠做分散剂和稳定剂,紫外光照射协同作用,通过光还原法成功制备得到了膨润土载纳米银抗菌剂。采用扫描电镜、高分辨透射电镜、能谱分析测试表征膨润土载纳米银抗菌剂的结构与性能,测试结果表明:膨润土载纳米银抗菌剂的膨润土片层中夹插有球状纳米银,纳米银颗粒直径为3~20 nm,其中大部分粒径小于8 nm。膨润土载纳米银抗菌剂中纳米银含银量为2.04wt%。膨润土载纳米银抗菌剂有很好的抗菌性能,对大肠杆菌的最小抑菌浓度(MIC)为25μg/m L,对金黄色葡萄球菌的最小抑菌浓度(MIC)为50μg/m L,能快速抑制细菌的生长。     

原位还原制备磺酸型水性聚氨酯/纳米银复合材料及其表征EI北大核心CSCD

使用水溶性聚酯多元醇(BY3301)和磺酸盐扩链剂氨基磺酸钠(A95)与四甲基苯二甲基二异氰酸酯(TMXDI)合成了磺酸型水性聚氨酯(SWPU)。在SWPU中原位还原纳米银(AgNPs)制备了磺酸型水性聚氨酯/纳米银(SWPU/AgNPs)复合乳液。涂膜之后测试了复合材料的力学性能、热性能和粘接性能的变化。同时使用动态光散射(DLS)和透射电镜(TEM)测试了乳液的粒径分布以及AgNPs的尺寸。结果表明,原位还原引入的AgNPs可以提高复合材料的力学性能和热性能,对于SWPU的粘接性能影响不大。SWPU在复合材料中还起到了稳定剂的作用,有效避免了AgNPs的团聚。TEM的研究显示复合材料中的AgNPs的形状为球形,粒径范围在5~40 nm。     

聚乙烯醇/纳米银薄膜的制备及其对黄骨鱼保鲜效果的研究

目的研究聚乙烯醇(PVA)/纳米银薄膜的抑菌性能,探索食品保鲜包装新方法。方法以PVA和水为基本原料,戊二醛为改性剂,用溶液流延法制备含有不同质量分数(1%,2%,3%)纳米银的PVA薄膜,分别表征其力学性能和耐水性能。将鱼肉用薄膜包裹,在4℃下贮藏,每隔3 d取样测定菌落数并进行感官分析。结果 PVA/纳米银薄膜对鱼肉有明显的抑菌作用,当纳米银添加质量分数为1%时,薄膜的拉伸强度为19.41 MPa,断裂伸长率为49%,力学性能良好;吸水率为32.2%,润湿角为55.1°,疏水性较好;与空白组相比,鱼肉货架期延长了4 d左右。结论质量分数为1%的纳米银能够增强薄膜的抑菌效果、有效维持鱼肉的感官品质,因此,在冷链运输中有很好的应用前景。     

原位还原制备磺酸型水性聚氨酯/纳米银复合材料及其表征

使用水溶性聚酯多元醇(BY3301)和磺酸盐扩链剂氨基磺酸钠(A95)与四甲基苯二甲基二异氰酸酯(TMXDI)合成了磺酸型水性聚氨酯(SWPU)。在SWPU中原位还原纳米银(AgNPs)制备了磺酸型水性聚氨酯/纳米银(SWPU/AgNPs)复合乳液。涂膜之后测试了复合材料的力学性能、热性能和粘接性能的变化。同时使用动态光散射(DLS)和透射电镜(TEM)测试了乳液的粒径分布以及AgNPs的尺寸。结果表明,原位还原引入的AgNPs可以提高复合材料的力学性能和热性能,对于SWPU的粘接性能影响不大。SWPU在复合材料中还起到了稳定剂的作用,有效避免了AgNPs的团聚。TEM的研究显示复合材料中的AgNPs的形状为球形,粒径范围在5~40 nm。     

添加β-环糊精/银复合抗菌剂的硅橡胶的制备及抗菌性能的研究

使用化学还原法,葡萄糖作为还原剂,β-CD作为稳定剂制备出β-CD/AgNPs复合抗菌剂,通过物理共混加入到医用液体硅橡胶中,得到抗菌性硅橡胶。通过UV-Vis、FT-IR、TEM、XRD检测AgNPs(银纳米颗粒)表面形态和相关结构,采用微量肉汤二倍稀释法和贴膜法检测β-CD/AgNPs复合抗菌剂、抗菌性硅橡胶的抗菌性。结果表明,当β-CD浓度为20mmol/L时,所得的AgNPs的紫外吸收峰为416nm,为典型AgNPs吸收峰;粒径为30nm,β-CD有效的包覆在AgNPs表面。而不加β-CD所制的Ag粒子没有明显的吸收峰且粒径较大。20mmol/Lβ-CD/AgNPs对大肠杆菌的最小抑制浓度为16μg/mL,添加到硅橡胶中含量为0.15%时抗菌率达99%,具有强抗菌作用。     

基于纳米银负载氧化石墨烯的新型聚乙烯复合材料

通过超声波辅助液相法将纳米银(AgNPs)与氧化石墨烯(GO)结合制得了一种新的负载纳米银的氧化石墨烯材料AgNPs@GO。分析表明在该材料中AgNPs主要被锚接在GO片层的含氧基团和缺陷上, 部分Ag单质被氧化为Ag ⁺离子并有部分GO被还原。AgNPs@GO能有效抑制铜绿假单胞菌生长, 其抑菌能力显著强于AgNPs和GO。将AgNPs@GO作为添加剂引入聚乙烯(PE)基体, 进一步制备了新型的AgNPs@GO掺杂PE复合材料0.48wt%-AgNPs@GO/PE, 相比PE和AgNPs掺杂PE复合材料, 0.48wt%-AgNPs@GO/PE具有更好的抑菌能力和更强的阻隔水蒸气性能, 并且在水和乙醇溶液中都具有较好的耐溶出性能。     

Multifunctional Starch-Based Sensor with Non-Covalent Network to Achieve “3R” Circulation

With the consumption of disposable electronic devices increasing, it is meaningful but also a big challenge to develop reusable and sustainable materials to replace traditional single-use sensors. Herein, a clever strategy for constructing a multifunctional sensor with 3R circulation (renewable, reusable, pollution-reducing biodegradable) is presented, in which silver nanoparticles (AgNPs) with multiple interactions are introduced into a reversible non-covalent cross-linking network composed of biocompatible and degradable carboxymethyl starch (CMS) and polyvinyl alcohol (PVA) to simultaneously obtain high mechanical conductivity and long-term antibacterial properties by a one-pot method. Surprisingly, the assembled sensor shows high sensitivity (gauge factor up to 4.02), high conductivity (0.1753 S m⁻¹), low detection limit (0.5%), long-term antibacterial ability (more than 7 days), and stable sensing performance. Thus, the CMS/PVA/AgNPs sensor can not only accurately monitor a series of human behavior, but also identify handwriting recognition from different people. More importantly, the abandoned starch-based sensor can form a 3R circulation. Especially, the fully renewable film still shows excellent mechanical performance, achieving reusable without sacrificing its original function. Therefore, this work provides a new horizon for multifunctional starch-based materials as sustainable substrates for replacing traditional single-use sensors.     

The cellular responses and antibacterial activities of silver nanoparticles stabilized by different polymers

Silver nanoparticles (AgNPs) are known for their excellent antibacterial activities. The possible toxicity, however, is a major concern for their applications. Three types of AgNPs were prepared in this study by chemical processes. Each was stabilized by a polymer surfactant, which was expected to reduce the exposure of cells to AgNPs and therefore their cytotoxicity. The polymer stabilizers included poly(oxyethylene)-segmented imide (POEM), poly(styrene-co-maleic anhydride)-grafting poly(oxyalkylene) (SMA) and poly(vinyl alcohol) (PVA). The cytotoxicity of these chemically produced AgNPs to mouse skin fibroblasts (L929), human hepatocarcinoma cells (HepG2), and mouse monocyte macrophages (J774A1) was compared to that of physically produced AgNPs and gold nanoparticles (AuNPs) as well as the standard reference material RM8011 AuNPs. Results showed that SMA-AgNPs were the least cytotoxic among all materials, but cytotoxicity was still observed at higher silver concentrations (>30 ppm). Macrophages demonstrated the inflammatory response with cell size increase and viability decrease upon exposure to 10 ppm of the chemically produced AgNPs. SMA-AgNPs did not induce hemolysis at a silver concentration below 1.5 ppm. Regarding the antibacterial activity, POEM-AgNPs and SMA-AgNPs at 1 ppm silver content showed 99.9% and 99.3% growth inhibition against E. coli, while PVA-AgNPs at the same silver concentration displayed 79.1% inhibition. Overall, SMA-AgNPs demonstrated better safety in vitro and greater antibacterial effects than POEM-AgNPs and PVA-AgNPs. This study suggested that polymer stabilizers may play an important role in determining the toxicity of AgNPs.     

Antibacterial potential of silver nanoparticles biosynthesised using Canarium ovatum leaves extract

Silver nanoparticles (AgNPs) have been extensively used as antibacterial agents, owing to their ease of preparation. In the present study, leaves extract of Canarium ovatum have been employed for the biosynthesis of silver nanoparticles (CO‐AgNPs). CO‐AgNPs were synthesised under very mild, eco‐friendly manner where the plant extract acted both as reducing and capping agent. These AgNPs were synthesised by taking into account several parameters, that included, time of reaction, concentration of AgNO₃, amount of extract and temperature of reaction. The optimisation studies suggested efficient synthesis of CO‐AgNPs at 25°C when 1.5 mM AgNO₃ was reduced with 1:20 ratio of plant extract for 40 min. Size determination studies done on dynamic light scattering and scanning electron microscope suggested of spherical shape nanoparticles of size 119.7 ± 7 nm and 50–80 nm, respectively. Further, characterisations were done by Fourier transform infrared and energy‐dispersive X‐ray spectroscopy to evaluate the functional groups and the purity of CO‐AgNPs. The antibacterial efficacy of CO‐AgNPs was determined against the bacterial strain Pseudomonas aeruginosa. As evident from disc diffusion method studies, CO‐AgNPs remarkably inhibited the growth of the tested microorganism. This study suggested that C. ovatum extract efficiently synthesises CO‐AgNPs with significant antibacterial properties and can be good candidates for therapeutics.Inspec keywords: antibacterial activity, nanoparticles, silver, nanofabrication, particle size, light scattering, scanning electron microscopy, Fourier transform infrared spectra, X‐ray chemical analysis, microorganisms, biomedical materials, nanomedicineOther keywords: antibacterial potential, silver nanoparticles, biosynthesis, Canarium ovatum leave extract, plant extract, reducing agent, capping agent, antibacterial agents, reaction time, reaction temperature, dynamic light scattering, scanning electron microscopy, spherical shape nanoparticles, Fourier transform infrared spectroscopy, functional groups, bacterial strain Pseudomonas aeruginosa, disc diffusion method, microorganism, energy‐dispersive X‐ray spectroscopy, temperature 25 degC, time 40 min, Ag     

Green synthesized silver nanoparticle from Allium ampeloprasum aqueous extract: Characterization,antioxidant activities,antibacterial and cytotoxicity effects

In the current study for the first time, silver nanoparticles (AgNPs) were biosynthesized by reducing agents from hot water extract of Allium ampeloprasum, an antibacterial and anti-inflammatory edible plant. UV–vis. spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering, X-ray diffractometric, and transmission electron microscopy (TEM) analyses have been applied to confirm the formation of biosynthesized AgNPs. Total phenol content and antioxidant activities of AgNPs and extract together with their antibacterial and cytotoxic properties, were evaluated. According to TEM, AgNPs were spherical with a diameter of 8–50 nm. Total phenolic compounds were 15.58 μg/mL, and 10.94 μg/mL at a concentration of 150 μg/mL for the A. ampeloprasum extract and the biosynthesized AgNPs, respectively. Biosynthesized AgNPs showed significant antioxidant activity (81%) as compared to A. ampeloprasum extract (32%) and were active on multi-drug resistant P. aeruginosa. Besides, the cytotoxic activity response was also demonstrated that AgNPs were more potent than the A. ampeloprasum extract and showed high activity against Hela cell line with an IC₅₀ value of less than 25 µg/mL. In conclusion, AgNPs synthesized by A. ampeloprasum extract with excellent antioxidant and antibacterial effects and acceptable cytotoxicity on cervical cancer cells have the potential to be used in biological applications.     

Speciation analysis of silver nanoparticles and silver ions in antibacterial products and environmental waters via cloud point extraction-based separation

The rapid growth in commercial use of silver nanoparticles (AgNPs) will inevitably increase silver exposure in the environment and the general population. As the fate and toxic effects of AgNPs is related to the Ag(+) released from AgNPs and the transformation of Ag(+) into AgNPs, it is of great importance to develop methods for speciation analysis of AgNPs and Ag(+). This study reports the use of Triton X-114-based cloud point extraction as an efficient separation approach for the speciation analysis of AgNPs and Ag(+) in antibacterial products and environmental waters. AgNPs were quantified by determining the Ag content in the Triton X-114-rich phase with inductively coupled plasma mass spectrometry (ICPMS) after microwave digestion. The concentration of total Ag(+), which consists of the AgNP adsorbed, the matrix associated, and the freely dissolved, was obtained by subtracting the AgNP content from the total silver content that was determined by ICPMS after digestion. The limits of quantification (S/N = 10) for antibacterial products were 0.4 μg/kg and 0.2 μg/kg for AgNPs and total silver, respectively. The reliable quantification limit was 3 μg/kg for total Ag(+). The presence of Ag(+) at concentrations up to 2-fold that of AgNPs caused no effects on the determination of AgNPs. In the cloud point extraction of AgNPs in antibacterial products, the spiked recoveries of AgNPs were in the range of 71.7-103% while the extraction efficiencies of Ag(+) were in the range of 1.2-10%. The possible coextracted other silver containing nanoparticles in the cloud point extraction of AgNPs were distinguished by transmission electron microscopy (TEM), scanning electron microscopy (SEM)- energy dispersive spectroscopy (EDS), and UV-vis spectrum. Real sample analysis indicated that even though the manufacturers claimed nanosilver products, AgNPs were detected only in three of the six tested antibacterial products.     

Facile photoreductive synthesis of silver nanoparticles for antimicrobial studies

In the present work, silver nanoparticles stabilized with L-Cysteine (L-Cys) were synthesized based on the one-pot green process by UV irradiation, in which L-Cysteine acts as biological capping agent. The composition and morphological characteristics of the L-Cys capped AgNPs has been ascertained by different techniques such as UV–vis, FL, XRD, TEM, EDX, FTIR and CD analysis. The results demonstrated the formation of spherical nanoparticles of pure Ag° coated with L-Cys. The antibacterial tests on L-Cys capped AgNPs were performed, exerting effective antimicrobial activity both against E. coli and S. aureus, with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 21.9 μg/mL and 175 μg/mL, respectively. Considering this simple and green process, the approach may facilitate new approaches to the manufacture of AgNPs-based antibacterial agent.     

Silver nanoparticles-doped collagen–alginate antimicrobial biocomposite as potential wound dressing

Development of novel wound dressing with potent antibacterial activity is crucial for wound healing and tissue regeneration. In this work, we aim to prepare silver nanoparticles (AgNPs)-doped collagen–alginate (CA–AgNPs) biocomposite, which may possess antibacterial activity and be used as wound dressing. AgNPs were synthesized using NaBH₄ as reducing agent and polyvinyl pyrrolidone as stabilizing agent. The formation of the AgNPs was confirmed by ultraviolet–visible spectrophotometer and transmission electron microscopy. Then, the as-prepared AgNPs were mixed with sodium alginate and collagen to obtain CA–AgNPs biocomposite. The CA–AgNPs biocomposite was fully characterized to verify the presence of AgNPs in the biocomposite. In vitro cytotoxicity assay illustrated that the CA–AgNPs biocomposite possessed negligible cytotoxicity at low AgNPs concentration. Furthermore, the antibacterial activity of the CA–AgNPs biocomposite was assessed against Staphylococcus aureus and Escherichia coli through agar diffusion method. Inhibition zone indicated that CA–AgNPs biocomposite possessed much higher antimicrobial activity than that of CA biocomposite, which strengthened with the increase in the AgNPs contents. Taken together, our finding suggested that the CA–AgNPs biocomposite showed strong potential as wound dressing.     

石墨烯-银纳米粒子复合材料的制备及表征

以无毒、绿色的葡萄糖为还原剂, 在没有稳定剂、温和的液相反应条件下, 同时还原氧化石墨和银氨溶液中的银氨离子, 原位制备石墨烯-银纳米粒子复合材料. 采用X射线衍射、红外吸收光谱、拉曼光谱、扫描电镜和透射电子显微镜对所制备的石墨烯-银纳米粒子复合材料进行了表征. 结果表明: 氧化石墨和银离子在反应过程中同时被葡萄糖还原, 银纳米粒子均匀分布于石墨烯片层之间, 生成的银纳米粒子中大多数存在着孪晶界, 银纳米粒子的大小和分布受硝酸银用量的影响, 在合适的银离子浓度下, 负载在石墨烯片层上的银纳米粒子的粒径分布集中在25 nm左右; 复合材料中石墨烯的拉曼信号由于银粒子的存在增强了7倍.     

Autoclave‐assisted synthesis of AgNPs in Z. officinale extract and assessment of their cytotoxicity,antibacterial and antioxidant activities

In this study, the authors synthesised silver nanoparticles (AgNPs) using autoclave as a simple, unique and eco‐friendly approach. The effect of Zingiber officinale extract was evaluated as a reducing and stabiliser agent. According to transmission electron microscopy results, the AgNPs were in the spherical shape with a particle size of ∼17 nm. The biomedical properties of AgNPs as antibacterial agents and free radical scavenging activity were estimated. Synthesised AgNPs showed significant 1,1‐diphenyl‐2‐picryl‐hydrazyl free radical scavenging. Strong bactericidal activity was shown by the AgNPs on Gram‐positive and Gram‐negative bacteria. A maximum inhibition zone of ∼14 mm was obtained for epidermidis at a concentration of 60 μg/ml for sample fabricated at 24 h. The AgNPs also showed a significant cytotoxic effect against MCF‐7 breast cancer cell lines with an half maximal inhibitory concentration value of 62 μg/ml in 24 h by the MTT assay. It could be concluded that Z. officinale extract can be used effectively in the production of potential antioxidant and antimicrobial AgNPs for commercial application.Inspec keywords: nanoparticles, cancer, organic compounds, antibacterial activity, particle size, microorganisms, silver, visible spectra, ultraviolet spectra, biomedical materials, biochemistry, nanofabrication, free radicals, nanomedicine, toxicology, cellular biophysics, transmission electron microscopyOther keywords: unique approach, eco‐friendly approach, zingiber officinale, reducing agent, stabiliser agent, transmission electron microscopy results, antibacterial agents, free radical scavenging activity, synthesised AgNPs, 1‐diphenyl‐2‐picryl‐hydrazyl free radical scavenging, strong bactericidal activity, antimicrobial AgNPs, autoclave‐assisted synthesis, antioxidant activities, cytotoxic effect, silver nanoparticles, autoclave, time 24.0 hour     

Poly(vinyl alcohol)-based composite film with Ag-immobilized TEMPO-oxidized nano-tea cellulose for improving photocatalytic performance

In the present study, we report a simple and eco-friendly method for the synthesis and immobilization of silver nanoparticles (AgNPs) onto functional films using green tea extract as a reducing and capping agent. The freestanding flexible immobilized AgNPs composite was obtained from a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated tea cellulose (TTC) process. Scanning electron microscopy analysis revealed the homogeneous coating of the AgNPs on the surface of the TTC nanofibers. Ag-TTC-poly(vinyl alcohol) (PVA) composite film was prepared through a simple solvent casting method, which displayed higher antioxidant activity than the TTC-PVA film, and the rate of release of Ag was reduced owing to the immobilized AgNPs. The photocatalytic performance of Ag-TTC-PVA composite film was evaluated along with the investigations of the optical transparency, morphology, and thermal properties. Ag-TTC-PVA composite film showed enhanced photocatalytic property than TTC-PVA film. This study presents a simple approach for the green synthesis of materials with controlled leakage based on Ag-TTC-PVA composite film, which has good potential application prospects in the development for the photocatalytic degradation of certain toxic dyes, thereby paving the way for waste treatment.