首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Silver nanoparticles (AgNPs) have promising potential in biomedicine, energy science, optics, and health care applications. We synthesized AgNPs using plant, Kalopanax pictus leaf extract. UV-visible spectrophotometric study showed the characteristic peak for AgNPs at wavelength 430 nm. The optical density at 430 nm increased after addition of plant leaf extract, indicating increase in formation of nanoparticles. Comparative time course analyses for AgNP synthesis carried out at different reaction temperatures (20, 60, and 90 °C) revealed higher reaction rate for K. pictus than Magnolia kobus plant leaf extract, which showed highest AgNP synthesis rate in the previous report. Electron microscopy analyses confirmed the presence of well dispersed AgNPs, predominantly with spherical shapes. In transmission electron microscopy, the particle size decreased with increase in temperature. Electron dispersive X-ray spectroscopy analyses indicated that Ag content increased with increase in reaction temperature. Fourier transform-infrared spectroscopy studies revealed capping of bioorganics from plant to the synthesized AgNPs. The antimicrobial activity of the synthesized AgNPs against Escherichia coli increased with increase in reaction temperature. The observations in this study will prove beneficial in approaching rapid synthesis of AgNPs and their antimicrobial application.  相似文献   

2.
The development of eco-friendly and nontoxic processes for the synthesis of nanoparticles is one of the most important discussed issues in nanotechnology science. This study reports the green synthesis of silver nanoparticles (AgNPs) using aqueous extract of leaf, stem, and root of Avicennia marina, the native and dominant mangrove plant in southern Iran. Among the different plant parts, the extract of leaves yielded the maximum synthesis of AgNPs. Synthesized AgNPs were investigated using UV–visible spectrophotometry, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and Fourier transform infrared (FTIR) spectroscopy. Absorption spectrum in 420?nm confirmed the synthesis of AgNPs. TEM images revealed that the synthesized AgNPs had the same spherical morphology with a size range between 0 and 75?nm. The distribution size histogram indicated that the most frequent particles were in the range of 10–15?nm and the mean size of nanoparticles was 17.30?nm. The results of SEM image showed nanoparticles with a size range between 15 and 43?nm. XRD pattern indicated the crystalline nature of synthesized nanoparticles. EDS results confirmed the presence of elements like silver, carbon, chlorine, nitrogen, and oxygen in the nanoparticles produced from leaf extract. Silver had the maximum percentage of formation, 51.6%. FTIR indicated the presence of different functional groups such as amines, alcohol, alkanes, phenol, alkyl halides, and aromatic loops in the synthesis process. Green biosynthesis of AgNPs using aqueous extract of native A. marina appears rapid, reliable, nontoxic, and eco-friendly.  相似文献   

3.
With advances in nanotechnology, pure silver has been recently engineered into nanometer‐sized particles (diameter <100 nm) for use in the treatment of wounds. In conjunction with other studies, we previously demonstrated that the topical application of silver nanoparticles (AgNPs) can promote wound healing through the modulation of cytokines. Nonetheless, the question as to whether AgNPs can affect various skin cell types—keratinocytes and fibroblasts—during the wound‐healing process still remains. Therefore, the aim of this study was to focus on the cellular response and events of dermal contraction and epidermal re‐epithelialization during wound healing under the influence of AgNPs; for this we used a full‐thickness excisional wound model in mice. The wounds were treated with either AgNPs or control with silver sulfadiazine, and the proliferation and biological events of keratinocytes and fibroblasts during healing were studied. Our results confirm that AgNPs can increase the rate of wound closure. On one hand, this was achieved through the promotion of proliferation and migration of keratinocytes. On the other hand, AgNPs can drive the differentiation of fibroblasts into myofibroblasts, thereby promoting wound contraction. These findings further extend our current knowledge of AgNPs in biological and cellular events and also have significant implications for the treatment of wounds in the clinical setting.  相似文献   

4.
Silver nanoparticles (AgNPs) have been used as antibacterial, antifungal, antiviral, anti-inflammtory, and antiangiogenic due to its unique properties such as physical, chemical, and biological properties. The present study was aimed to investigate antibacterial and anti-biofilm activities of silver nanoparticles alone and in combination with conventional antibiotics against various human pathogenic bacteria. Here, we show that a simple, reliable, cost effective and green method for the synthesis of AgNPs by treating silver ions with leaf extract of Allophylus cobbe. The A. cobbe-mediated synthesis of AgNPs (AgNPs) was characterized by ultraviolet-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Furthermore, the antibacterial and anti-biofilm activity of antibiotics or AgNPs, or combinations of AgNPs with an antibiotic was evaluated using a series of assays: such as in vitro killing assay, disc diffusion assay, biofilm inhibition, and reactive oxygen species generation in Pseudomonas aeruginosa, Shigella flexneri, Staphylococcus aureus, and Streptococcus pneumonia. The results suggest that, in combination with antibiotics, there were significant antimicrobial and anti-biofilm effects at lowest concentration of AgNPs using a novel plant extract of A. cobbe, otherwise sublethal concentrations of the antibiotics. The significant enhancing effects were observed for ampicillin and vancomycin against Gram-negative and Gram-positive bacteria, respectively. These data suggest that combining antibiotics and biogenic AgNPs can be used therapeutically for the treatment of infectious diseases caused by bacteria. This study presented evidence of antibacterial and anti-biofilm effects of A. cobbe-mediated synthesis of AgNPs and their enhanced capacity against various human pathogenic bacteria. These results suggest that AgNPs could be used as an adjuvant for the treatment of infectious diseases.  相似文献   

5.

In the current study, biogenic silver nanoparticles (U-AgNPs) were synthesized using marine green macro-algal Ulva lactuca extract, and evaluated mechanism behind its anticancer activity against the Human colon cancer (HCT-116). The biogenic U-AgNPs were characterized using various physiochemical techniques. The TEM micrographs confirmed the spherical morphology of synthesized U-AgNPs, with a mean size of 8–14 nm. EDX spectrum as well as ICP-OES confirmed that AgNPs was nearly 90% purity for silver. FTIR Spectra analysis of U-AgNPs confirmed U. lactuca extract bioactive molecules presence over U-AgNPs surface as a stabilizing agent, thereby improving biocompatibility. The cytotoxicity study revealed the dose dependent cell death in colon cancer cells with no loss of viability in normal human colon epithelial cells. Furthermore, the fluorescence micrographs of nucleus staining assay revealed the DNA fragmentation and nucleus condensation of cancer cells treated with U-AgNPs, indicating an apoptosis-mediated cell death. The western bolt and RT-PCR analysis of U-AgNPs treated cancer cells showed the rise in proapoptotic markers (P53, Bax, and P21) and decline in anti-apoptotic markers (Bcl-2), thus confirming the p53-dependent apoptosis mediated cell death in HCT-116. Overall, our study concluded that novel biogenic U-AgNPs nanoparticles, synthesized using marine green macro-algal U. lactuca extract showed efficient anticancer activity against HCT-116 cell line and hence could work as potential therapeutic agent for targeted anti-cancer therapy.

  相似文献   

6.
An innovative concept of spontaneous film dressing has been designed as sprayed hydrogel dressings (SHD) using a blend of polyvinyl alcohol (PVA) and sodium alginate (SA) as synthetic and natural polymeric components and, were crosslinked with boric acid and calcium chloride, respectively. Silver nanoparticles (AgNPs) are synthesized by green chemistry using Ficus benghalensis extract (FB) and were characterized by SEM and zeta sizer. FTIR spectra show polymeric interaction with AgNPs, while SEM images show outer surface of the SHD film. Equilibrium swelling and degradation in aqueous media (distilled water and buffers) are found to be dependent upon PVA/SA ratio. Polymeric combination exhibit pseudoplastic behavior with Farrow's constant >1. Uniformly distributed AgNPs (particle size ~27.55 ± 2.01 nm), high water retention (~13 fold), and biodegradable (~5 days) nature of dressing along with sustained release profile of both AgNPs and extract with concentration‐dependent antimicrobial activity have been observed for 24 h. Self shaped, biodegradable, aseptic, prolong anti‐oxidative, non‐hemolytic, blood compatible, and hemostatic properties of SHD film appears as promising dressing for superficial wounds. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43260.  相似文献   

7.

In this study, we look into the biogenic synthesis of (AgNPs) utilizing a simple and environmentally friendly method based on an aqueous extract of Moringa Oleifera (MO). The synthesized MOAgNPs were characterized using a UV–Visible spectrophotometry, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra and TEM image which confirmed the spherical shape of MOAgNPs with particle size range of 5–50 nm with an average particle size of 38.7 nm. Significantly, the prepared MOAgNPs showed high pesticidal activity towards Spodoptera littoralis. MOAgNPs also exhibited strong antibacterial activities against Gram-positive and Gram-negative bacteria. The prepared MOAgNPs were screened for their cytotoxic effect against (HCT-116), (HepG-2) and (MCF-7) carcinoma cell lines. Finally, the synthesized MOAgNPs have been used as a catalyst for the reduction of 2,4-Dinitrophenol using NaBH4 to 2,4-Diaminophenol. Taken together, the outstanding catalytic and biological activities of the synthesized MOAgNPs entitled them for applications as catalyst, pesticidal, antibacterial and anticancer agents in medical applications.

  相似文献   

8.
This study is aimed at the development of a composite wound dressing containing nanosilver loaded polyvinyl alcohol (PVA) nanogels. The PVA nanogels were prepared by fructose induced reduction of silver nitrate within PVA gel to develop nanosilver nanogel (nGel). The influence of various synthesis parameters on PVA nanogel formation was investigated. The particle size of the nanogels, as evaluated by transmission electron microscopy was observed to be in the range of 10–50 nm. Glycerol was added to the nGel system and this composition, nGel/Glc, was coated on cotton fabric to develop a composite wound dressing. The cumulative release of silver from the dressing was found to be ~36% of the total loading after 48 h. Even at such low concentrations, high antibacterial efficiency was achieved against both gram positive and gram negative bacteria. In vivo wound healing studies were carried out over a period of 21 days on full-thickness skin wounds created on Swiss albino mice. Fast healing was observed in nGel/Glc treated wounds with minimum scarring, as compared to other groups. These results suggest that nGel/Glc based dressing material could be promising candidates for wound dressing applications.  相似文献   

9.
以无患子提取液为还原剂,制备了含有纳米银的无患子复合抗菌液,考察了无患子提取液用量、温度、硝酸银摩尔浓度等因素对纳米银形貌和粒径的影响,并借助UV-Vis可见分光光谱、X射线衍射(XRD)以及透射电子显微镜(TEM)对产物进行表征;通过抑菌环法探讨了复合抗菌液对大肠杆菌的抗菌活性。由UV-Vis图谱可知,复合抗菌液等离子体共振吸收峰(SPR)在418 nm左右,说明该复合抗菌液中有纳米银的存在;XRD图表明合成的纳米银为面心立方结构;TEM图表明合成纳米银粒径为10~40 nm。由此获得的含有纳米银的无患子复合抗菌液对大肠杆菌表现出显著协同抗菌活性,抑菌圈直径变大。  相似文献   

10.
Skin loss can be caused by accident, burn, trauma, chronic wounds, and diseases, which is severely aggravated by multidrug‐resistant bacterial infections. Soft hybrids based on biopolymers combined with silver nanoparticles (AgNPs) have potential applications as wound dressing supports and skin tissue repair. Thus, our study focused on the design, green synthesis, and comprehensive characterization of carboxymethyl cellulose (CMC–AgNP) nanocomposites for producing hydrogel membranes, with tunable physicochemical properties, cytocompatibility, and biocidal activity for potential application as wound dressing and skin repair. These nanocomposites were prepared using CMC with two degrees of carboxymethylation, distinct concentrations of citric acid (CA) crosslinker, and AgNPs by in situ chemical reduction, forming hybrid membranes by the solvent casting method. The results demonstrated that superabsorbent hydrogels were produced with swelling and degradation behaviors dependent on the concentration of CA crosslinker, degree of carboxymethylation of CMC, and content of AgNP in the matrices. Moreover, the Fourier transform infrared spectroscopy analysis evidenced that the CMC functional groups (e.g., ? COOH and ? OH) were directly involved in the chemical reactions for the formation of AgNPs and hydrogel crosslinking pathway. These nanocomposites were cytocompatible using in vitro 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyltetrazolium bromide cell viability assay with of human embryonic kidney cells. Conclusively, the CMC–AgNP nanohybrids demonstrated to be simultaneously non‐toxic combined with highly effective antibacterial activity against gram‐positive multi‐resistant wound/skin pathogens (Staphylococcus aureus) and moderate effect towards gram‐negative strains (Escherichia coli and Pseudomonas aeruginosa). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45812.  相似文献   

11.
Since antiquity, silver-based therapies have been used in wound healing, wound care and management of infections to provide adequate healing. These therapies are associated with certain limitations, such as toxicity, skin discolouration and bacterial resistance, which have limited their use. As a result, new and innovative wound therapies, or strategies to improve the existing therapies, are sought after. Silver nanoparticles (AgNPs) have shown the potential to circumvent the limitations associated with conventional silver-based therapies as described above. AgNPs are effective against a broad spectrum of microorganisms and are less toxic, effective at lower concentrations and produce no skin discolouration. Furthermore, AgNPs can be decorated or coupled with other healing-promoting materials to provide optimum healing. This review details the history and impact of silver-based therapies leading up to AgNPs and AgNP-based nanoformulations in wound healing. It also highlights the properties of AgNPs that aid in wound healing and that make them superior to conventional silver-based wound treatment therapies.  相似文献   

12.
Abstract

The objective of this present work is to optimize and prepare silver nanoparticles(AgNPs) in Dioctyl sodium sulfosuccinate (AOT) microemulsion (ME) for oral use and to investigate its antibacterial and anticancer activity in vitro and in vivo. In vitro drug release study confirmed that faster release of drug at the tumor cells compared to the blood circulation. It also showed a potential antibacterial activity against pathogenic bacteria. The optimized AgNPs loaded ME confirmed significant cytotoxicity against MCF-7 cancer cell line with IC50 16.72?±?0.014?μg/mL and significant reduction in solid Ehrlich tumor growth in compared to the control, placebo and pure drug.  相似文献   

13.
Silver nanoparticles (AgNPs) loaded antibacterial micelles were fabricated utilizing the coordinate interaction between silver ion (Ag+) and methoxy-poly(ethylene glycol)-block-poly(acrylamide-co-acrylonitrile) followed by in situ reduction. This micelle was characterized by X-ray photoelectron spectroscopy, transmission electron microscopy, and dynamic light scattering. The upper critical solution temperature of Ag+-loaded micelles was dependent on Ag+ concentration. The AgNPs were approximately 4 nm in diameter and homogenously distributed in the micelles. The AgNPs-loaded micelle displayed high stability during a one week study and excellent antibacterial activity against gram-negative Escherichia coli and was of acceptable toxicity toward human embryonic hepatocytes.  相似文献   

14.
Electrospun nanofibrous membranes (ENMs) were fabricated based on chitosan/poly(vinyl alcohol) (CS/PVA) with a 70/30 mass ratio containing silver nanoparticles (AgNPs) via the electrospinning method. AgNPs were produced on the surface of CS/PVA nanofibers by adding AgNO3 to a CS/PVA blend solution as a silver rendering component. The presence of AgNPs in the polymer blend solution was detected by UV spectrophotometry. The morphology of nanofibers before and after cross-linking with glutaraldehyde was investigated by the field emission scanning electron microscopy. The formation and size distribution of AgNPs onto the surface of nanofibers were observed by transmission electron microscopy and confirmed by energy dispersing X-ray spectroscopy. As-spun and cross-linked CS/PVA nanofibers revealed a smooth surface with diameters ranging from 58 to 73 nm and 95 to 109 nm, respectively. The effect of AgNP formation on the chemical structure of nanofibers was explored by Fourier transform infrared spectroscopy. Static and dynamic antibacterial filtration efficiencies of CS/PVA ENMs, containing differing amounts of AgNO3, have been tested against Escherichia coli, a gram negative bacterium. The antibacterial assessment results exhibited a significant increase in both static and dynamic antibacterial filtration efficiencies of the prepared CS/PVA ENMs by addition of AgNO3 as a bactericidal agent.  相似文献   

15.
Polyvinyl chloride (PVC) was modified via substitution reaction with 2‐aminothiazole and ethyl 2‐aminothiazole‐4‐carboxylate separately in the absence and in presence of silver (AgNPs) or copper (CuNPs) nanoparticles, using metal salts as precursors, in 3% (w/w) with respect to PVC. The functionalized PVC‐nanocomposites have been characterized via FTIR, 1HNMR spectroscopic analyses, in addition to the morphological investigation such as scanning (SEM) and transmission electron microscopy (TEM). Spectral data confirmed the introduction of the thiazole (ester) to the PVC backbone. TEM analysis showed that the sizes of the AgNPs and CuNPs have fallen in the range of 10–30 nm and 30–50 nm for the prepared nanocomposites, respectively. Evaluating the photostability of modified nanocomposites was estimated by following the extent of discoloration for UV‐irradiated samples colorimetrically in accordance with the irradiation time. The antimicrobial activity of the modified nanocomposites was explored against three Gram+ve bacteria (Bacillus subtilis, Staphylococcus aureus, and Streptococcus faecalis), three Gram‐ve bacteria (Escherichia coli, Neisseria gonorrhoeae, and Pseudomonas aeruginosa), and two fungi (Candida albicans and Aspergillus flavus). Aminothiazole (ester)‐functionalized PVC exhibited significant antimicrobial efficiencies against the investigated pathogens. However, incorporation of AgNPs or CuNPs to the modified PVC enhanced their inhibitory effect against the microorganisms under investigation. J. VINYL ADDIT. TECHNOL., 25:E137–E146, 2019. © 2018 Society of Plastics Engineers  相似文献   

16.
Silver nanoparticles (AgNPs) were synthesized by a facile, mild and green method using dopamine as a reducing and stabilizing agent and were introduced to waterborne polyurethane (WPU) via an in situ emulsification method to prepare antibacterial nanocomposite films. The formation of AgNPs was characterized by UV–visible spectroscopy and XRD. The dispersion of AgNPs was confirmed by TEM and the thermal stability of WPU/Ag nanocomposites was confirmed by TGA. The results showed that AgNPs were uniformly dispersed in the WPU matrix. The introduction of AgNPs significantly improved the thermal stability of WPU films. With incorporation of 0.1 wt% AgNPs, a five-fold increase in the tensile strength was achieved without sacrificing the ultimate strain. The WPU/Ag nanocomposite films showed antibacterial activity against Escherichia coli and Staphylococcus aureus. © 2021 Society of Industrial Chemistry.  相似文献   

17.
Elaeis guineensis of the Arecaceae family is widely used in the traditional medicine of societies in West Africa for treating various ailments. To validate the ethnotherapeutic claims of the plant in skin diseases, wound healing activity was studied. The results showed that E. guineensis leaf extract had potent wound healing capacity as evident from the better wound closure (P < 0.05), improved tissue regeneration at the wound site, and supporting histopathological parameters pertaining to wound healing. Matrix metalloproteinases expression correlated well with the results thus confirming efficacy of E. guineensis in the treatment of the wound. E. guineensis accelerated wound healing in rats, thus supporting its traditional use. The result of this study suggested that, used efficiently, oil palm leaf extract is a renewable resource with wound healing properties.  相似文献   

18.
Silver nanoparticles (AgNPs) were successfully synthesized from the reduction of Ag+ using AgNO3 solution as a precursor and Brassica rapa var. japonica leaf extract as a reducing and capping agent. This study was aimed at synthesis of AgNPs, exhibiting less toxicity with high antibacterial activity. The characterization of AgNPs was carried out using UV–Vis spectrometry, energy dispersive X-ray spectrometry, fourier transform infrared spectrometry, field emission scanning electron microscopy, X-ray diffraction, atomic absorption spectrometry, and transmission electron microscopy analyses. The analyses data revealed the successful synthesis of nano-crystalline Ag possessing more stability than commercial AgNPs. The cytotoxicity of Brassica AgNPs was compared with commercial AgNPs using in vitro PC12 cell model. Commercial AgNPs reduced cell viability to 23% (control 97%) and increased lactate dehydrogenase activity at a concentration of 3 ppm, whereas, Brassica AgNPs did not show any effects on both of the cytotoxicity parameters up to a concentration level of 10 ppm in PC12 cells. Moreover, Brassica AgNPs exhibited antibacterial activity in terms of zone of inhibition against E. coli (11.1?±?0.5 mm) and Enterobacter sp. (15?±?0.5 mm) which was higher than some previously reported green-synthesised AgNPs. Thus, this finding can be a matter of interest for the production and safe use of green-AgNPs in consumer products.  相似文献   

19.
Suitability of Ficus benghalensis leaf powder for the adsorptive removal of Cobalt(II) from aqueous solutions is exhaustively studied and is reported in this article. Experimentation based on response surface methodology is conducted to understand the interaction among the variables—metal ion concentration, adsorbent dosage, initial solution pH and temperature that are of significance in the treatment. A 20?mg?L?1 of Cobalt(II) solution, treated with 25?g?L?1 of adsorbent at a pH of 5.0 and a temperature of 303?K, yielded 98.73% removal of Cobalt(II). Langmuir isotherm proved to be a better model representation of the equilibrium. Adsorption kinetics is of pseudo second rate form. Maximum sorption capacity of F. benghalensis leaf powder, qmax, is found to be 5.65?mg?g?1. Adsorption is endothermic and spontaneous in nature. Study on surface morphology is included in the study.  相似文献   

20.
A nanocomposite reservoir‐type hydrogel dressing of poly vinyl alcohol (PVA) was fabricated by a freeze–thaw method and loaded with silver‐nanoparticle‐coated chitosan wafers (Ag–CHWs). The Ag–CHWs were synthesized by a sonication technique with silver nitrate (AgNO3) and chitosan powder. Scanning electron microscopy images showed silver nanoparticles (AgNPs) with a size range of 10 ± 4 nm on the surface of the chitosan wafers, and the antibacterial efficacy (minimum inhibitory concentration) of the Ag–CHWs was measured against Pseudomonas aeruginosa (32 µg/mL), Staphylococcus aureus, (30 µg/mL) and Escherichia coli (32 µg/mL). The antimicrobial PVA hydrogel showed an improved tensile strength (~0.28 MPa) and gel content (~92%) in comparison with the blank hydrogels. Full‐thickness‐excision wound studies of the nanocomposite dressing on Wistar rats revealed enhanced wound contraction, improved inflammation response, re‐epithelization rate, neoangiogenesis, and granulation tissue formation in comparison to the control group. A flexible, biocompatible, nanocomposite reservoir dressing not only established the chitosan as a stabilizer but also proved the efficacious and safe utility of AgNPs toward chronic wound management. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43472.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号