A Physiological behavior and tolerance of Lactuca sativa to lead nitrate and silver nitrate heavy metals / Comportamento fisiológico e tolerância de Lactuca sativa aos metais pesados nitrato de chumbo e nitrato de prata

This study goal to evaluate the effects of different concentrations of lead (Pb) and silver (Ag) on germination, initial growth and anatomical alterations of Lactuca sativa L. Plants use various mechanisms to reduce the impacts caused by anthropic action, such as xenobiotic elements of soils and water contaminated by heavy metals. These metals were supplied as lead nitrate and silver nitrate and the following treatments were established: control for both metals, maximum dose of heavy metals, for arable soils, allowed by the National Council of the Environment (Ag = 25 mg. Kg-¹, Pb = 180 mg. Kg-¹), double (Ag = 50 mg. Kg-¹, Pb = 360 mg. Kg-¹) and triple (Ag = 75 mg. Kg-¹, Pb = 540 mg. Kg-¹) of this dosage. Vigor and germination tests of the seeds and possible anatomical changes in the leaves and roots of lettuce plants were performed. The species showed a high capacity to germinate under Pb and Ag stress, and the germination was never completely inhibited; however, the germination decreased with increasing Pb concentrations, but not under Ag stress. The use of increasing doses of metals reduced seed vigor and increased chlorophyll content. An increase in biomass was also observed in plants from treatments submitted to Pb. The phytotoxic effects of metals were more pronounced at 15 days after sowing. Anatomically, L. sativa was influenced by metal concentrations, and had a reduction of up to 79.9% in root epidermis thickness at the highest Pb concentration, although some structures did not suffer significant changes. The results suggest that L. sativa presents tolerance to high concentrations of heavy metals, showing possible mechanisms to overcome the stress caused by these metals. In this research lettuce possibly used the mechanism of exclusion of metals retaining Pb and Ag in the roots preserving the photosynthetic apparatus in the aerial part of the plants. In general, the chemical element Pb was more toxic than Ag, in these experimental conditions.

Este estudo teve como objetivo avaliar os efeitos de diferentes concentrações de chumbo (Pb) e prata (Ag) na germinação, crescimento inicial e alterações anatômicas de Lactuca sativa L. As plantas utilizam vários mecanismos para reduzir os impactos causados pela ação antrópica, como elementos xenobióticos de solos e água contaminada por metais pesados. Esses metais foram fornecidos como nitrato de chumbo e nitrato de prata e foram estabelecidos os seguintes tratamentos:controle para ambos os metais, dose máxima de metais pesados, para solos cultiváveis, permitida pelo Conselho Nacional do Meio Ambiente (Ag = 25mg.Kg-¹, Pb = 180mg.Kg-¹), dobro (Ag = 50mg.Kg-¹, Pb = 360mg.Kg-¹) e triplo (Ag = 75mg.Kg-¹, Pb = 540 mg.Kg-¹) desta dosagem. Foram realizados testes de vigor e germinação das sementes e possíveis alterações anatômicas nas folhas e raízes das plantas de alface. A espécie apresentou alta capacidade de germinar sob estresse de Ag e Pb, e a germinação nunca foi completamente inibida; entretanto, a germinação diminuiu com o aumento das concentrações de Pb, mas não sob estresse de Ag. O uso de doses crescentes dos metais, reduziu o vigor das sementes e aumentou o teor de clorofila. Também foi observado aumento da biomassa nas plantas a partir dos tratamentos submetidos ao Pb. Os efeitos fitotóxicos dos metais foram mais acentuados aos 15 dias após a semeadura. Anatomicamente, L. sativa foi influenciada pelas concentrações de metais, e teve uma redução de até 79,9% na espessura da epiderme radicular na maior concentração de Pb, embora algumas estruturas não tenham sofrido alterações significativas. Os resultados sugerem que L. sativa apresenta tolerância a altas concentrações de metais pesados, mostrando possíveis mecanismos para superar o estresse causado por esses metais. Nesta pesquisa a alface possivelmente utilizou o mecanismo de exclusão de metais retendo Pb e Ag nas raízes preservando o aparato [...].

Serum levels of immunoglobulin and complement in UTI of patients caused by Proteus mirabilis and using AgNPs as antiswarming.

The use of plant extracts represents a promising approach for the synthesis of silver nanoparticles (AgNPs). This study reports the low-cost, green synthesis of AgNPs using the extract of clove and black seeds. The biosynthesized AgNPs were confirmed and characterized by analysis of the spectroscopy profile of the UV-visible spectrophotometer. The purpose of the present study is to evaluate the inhibitory effect concentration (MIC) of AgNPs, clove, and black cumin seed extracts on the growth and swarming of P. mirabilis. Clinical isolates of P. mirabilis were isolated from patients suffering from urinary tract infections. Thirteen types of antibiotics were used in the present study to detect their ability to inhibit P. mirabilis's resistance. Immunological findings included the determination of serum levels of IgG, IgM, IgA and complement protein C3 and C4. Results showed that IgG and IgA concentrations significantly increased (1311.13 ± 72.54 and 279 ± 21.31) respectively in UTI patients in comparison to the healthy control group which was 1089.88 ± 37.33 and 117.611 ± 4.19 respectively, While IgM concentrations were increased non significantly in UTI patients (153.331 ± 6.45) in comparison to healthy control (145.2 ± 13.49). Complement components C3 showed a significant increase in UTI patients with mean values of 125.95 ± 6.22 compared to the control group with mean values of 55.191 ± 9.64, while C4 showed statically non-significant among UTI patients in comparison with the control group (35.195 ± 2.34 and 34.371 ± 1.22) respectively.

Silver Nanoparticles and Their Antibacterial Applications.

Silver nanoparticles (AgNPs) have been imposed as an excellent antimicrobial agent being able to combat bacteria in vitro and in vivo causing infections. The antibacterial capacity of AgNPs covers Gram-negative and Gram-positive bacteria, including multidrug resistant strains. AgNPs exhibit multiple and simultaneous mechanisms of action and in combination with antibacterial agents as organic compounds or antibiotics it has shown synergistic effect against pathogens bacteria such as Escherichia coli and Staphylococcus aureus. The characteristics of silver nanoparticles make them suitable for their application in medical and healthcare products where they may treat infections or prevent them efficiently. With the urgent need for new efficient antibacterial agents, this review aims to establish factors affecting antibacterial and cytotoxic effects of silver nanoparticles, as well as to expose the advantages of using AgNPs as new antibacterial agents in combination with antibiotic, which will reduce the dosage needed and prevent secondary effects associated to both.

Therapeutic potential of Moringa oleifera seed polysaccharide embedded silver nanoparticles in wound healing.

Wound healing is a complicated process that influences patient's life quality. Plant-based polysaccharide has recently gained interest in its use in wound dressing materials because of its biological compatibility, natural abundance, and ideal physiochemical properties. The present study reveals the potential of polysaccharide isolated from Moringa oleifera seed (MOS-PS) and its nanocomposite with silver (MOS-PS-AgNPs) as alternative materials for wound dressing. First, MOS-PS was isolated and structurally characterized by TLC, HPLC, FTIR, NMR, and GPC analyses. A green and simple method was used to synthesize AgNPs using MOS-PS as a stabilizing and reducing agent. The size, morphology, and structure of the MOS-PS-AgNPs were characterized by UV-Vis spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and zeta potential analysis. The results showed that the MOS-PS-AgNPs were spherically shaped, having no cytotoxicity toward mouse fibroblasts cells and promoting their in-vitro migration. Moreover, the MOS-PS-AgNPs displayed strong anti-microbial activity against wound infectious pathogenic bacteria. Finally, the MOS-PS-AgNPs were used for dressing animal wounds and its preliminary mechanism was studied by RT-PCR and histological analysis. The results showed that the MOS-PS-AgNPs can promote wound contraction and internal tissue growth well. Overall, our results indicated that the MOS-PS-AgNPs might be an excellent candidate for use as an optimal wound dressing material.

Hydrogel with silver nanoparticles synthesized by Mimosa tenuiflora for second-degree burns treatment.

In this work we use Mimosa tenuiflora (MtE) extracts as reducing agents to synthesize silver nanoparticles (AgMt NPs) which were characterized by DPPH and Total Polyphenols Assays, UV-visible, X-ray diffractometer (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and Thermogravimetric analysis (TGA). AgMt NPs possess average sizes of 21 nm and fcc crystalline structure, it was also confirmed that the MtE is present in the AgMt NPs even after the cleaning protocol applied. Subsequently, carbopol hydrogels were made and the MtE and the synthesized AgMt NPs were dispersed in different gels (MtE-G and AgMt NPs-G, respectively) at 100 µg/g concentration. The gels were characterized by UV-Vis, IR, and rheology. Antimicrobial tests were performed using Staphylococcus aureus and Escherichia coli. Burn wound healing was evaluated in a second-degree burn injury on a Wistar rats model for 14 days and additional skin biopsies were examined with histopathological analysis. Gel with commercial silver nanoparticles (Ag NPs) was prepared and employed as a control on the biological assays. Hydrogel system containing silver nanoparticles synthesized with Mimosa tenuiflora (AgMt NPs-G) is a promising therapeutic strategy for burn wound healing, this due to bactericidal and anti-inflammatory effects, which promotes a more effective recovery (in percentage terms) by damaged area.

BSA/Silver Nanoparticle-Loaded Hydrogel Film for Local Photothermal Treatment of Skin Cancer.

PURPOSE: To develop a hydrogel film containing bovine serum albumin (BSA)-coated silver nanoparticles (BSA/AgNP) and evaluate its applicability for topical photothermal treatment (PTT) of skin cancer. METHODS: BSA/AgNP-loaded hydrogel films were prepared and their swelling, bioadhesive, mechanical, and photothermal properties were characterized in vitro and in vivo. RESULTS: The synthesized BSA/AgNP exhibited a narrow size distribution with good size stability and, notably, possessed great photothermal activity that could stably maintain through repetitive laser irradiation. The BSA/AgNP-loaded hydrogel films showed favorable swelling, bioadhesive, tensile, and photothermal properties. Based on these results, when tested the anti-cancer effects in B16F10 s.c. tumor-bearing mice, the PTT with the topical treatment of BSA/AgNP-loaded hydrogel films could significantly inhibit the tumor growth by a single treatment with no apparent toxicity. CONCLUSIONS: Overall, the results of this study demonstrated that the BSA/AgNP-loaded hydrogel films may serve as an effective but safe topical PTT agent for the treatment of skin cancer.

Dietary supplementation of silver-silica nanoparticles promotes histological, immunological, ultrastructural, and performance parameters of broiler chickens.

Silver nanoparticles (AgNPs) have been used as a promising alternative to antibiotics in poultry feed. In this study, silver-doped silica nanoparticles (SiO2@AgNPs) were prepared in powder form, using starch, via the chemical reduction method and sol-gel technique followed by full characterization. SiO2@AgNPs were added to the poultry diet at three doses (2, 4, and 8 mg/kg diet). The safety of the oral dietary supplementation was estimated through the evaluation of the growth performance and hematological, biochemical, and oxidative parameters of birds. Moreover, the immunohistochemical examination of all body organs was also performed. Results of this study showed that SiO2@AgNPs have no negative effects on the growth performance and hematological, biochemical, and oxidative parameters of birds. Moreover, the immunohistochemical examination revealed the minimum inflammatory reactions and lymphoid depletion under a dose level of 8 mg/kg. In conclusion, SiO2@AgNPs could be considered as a promising and safe nano-growth promoter in broilers when added to poultry diet under a dose level of 4 mg/kg diet.

Utilization of Cladophora glomerata extract nanoparticles as eco-nematicide and enhancing the defense responses of tomato plants infected by Meloidogyne javanica.

Tomato (Solanum Lycopersicum L.) is an important vegetable crop that belongs to the family Solanaceae. Root-knot nematodes reflect the highly critical economically damaging genera of phytoparasitic nematodes on tomato plants. In this study, the eco-nematicide activity of freshwater green macroalga Cladophora glomerata aqueous extract and their synthesized silver nanoparticles (Ag-NPs) against root-knot nematodes Meloidogyne javanica was investigated on tomato plants. The formation and chemical structure of Ag-NPs was examined. The aqueous extract from C. glomerata was applied against the root-knot nematodes besides the biosynthesized green silver nanoparticles with 100, 75, 50, and 25% (S, S/2, S/3, S/4) concentrations. To investigate the plant response toward the Green Synthesized Silver Nanoparticles (GSNPs) treatment, expression profiling of Phenylalanine Ammonia-Lyase (PAL), Poly Phenol Oxidase (PPO), and Peroxidase (POX) in tomato were examined using Quantitative Real-Time PCR (Q-PCR). The results indicated that GSNPs from C. glomerata exhibited the highest eco-nematicide activity in the laboratory bioassay on egg hatchability and juveniles (J2S) mortality of M. javanica compared with the chemical commercial nematicide Rugby 60%. Also, results showed a significant reduction in galls number, egg masses, females per root system/plant, and mortality of juveniles. The results of PAL and PPO enzyme expression for the control plants remained relatively stable, while the plant inoculated with nematode M. javanica as well as the activity of genes in scope was increased from 14 to 28 Days after Nematode Inoculation (DANI). These activities were improved in inoculated plants and treated with C. glomerata extract and their green syntheses of Ag-NPs and the other plants treated with Rugby 60% (4 mL/L). The greatest activities of the three enzymes were evident after 14 days after the nematode inoculation. It can be concluded that the green synthesized nanoparticles using C. glomerata could be used as potent nematicides against M. javanica which induces the immune system to defend against nematode infection.

Mild temperature photothermal assisted anti-bacterial and anti-inflammatory nanosystem for synergistic treatment of post-cataract surgery endophthalmitis.

Rationale: Endophthalmitis, which is one of the severest complications of cataract surgeries, can seriously threaten vision and even lead to irreversible blindness owing to its complicated microenvironment, including both local bacterial infection and severe inflammation. It is urgent to develop a comprehensive treatment for both anti-bacterial and anti-inflammatory effects. Methods: Herein, we developed AuAgCu2O-bromfenac sodium nanoparticles (AuAgCu2O-BS NPs), which was designed to combine anti-bacterial and anti-inflammatory effects for integrated therapy of endophthalmitis after cataract surgery. The AuAgCu2O-BS NPs could eradicate methicillin-resistant Staphylococcus aureus (MRSA) bacterial strain relied on their photodynamic effects and the release of metal ions (Ag+ and Cu+) by the hollow AuAgCu2O nanostructures mediated mild photothermal effects. The anti-inflammatory drug, bromfenac sodium, released from the nanoparticles were able to significantly reduce the local inflammation of the endophthalmitis and promote tissue rehabilitation. In vivo bacterial elimination and anti-inflammation were confirmed by a postcataract endophthalmitis rabbit model. Results: Excellent antibacterial ability of AuAgCu2O-BS NPs was verified both in vitro and in vivo. Ophthalmological clinical observation and pathologic histology analysis showed prominent treatment of inflammatory reaction. Importantly, the mild temperature photothermal effect not only promoted the release of metal ions and bromfenac sodium but also avoided the thermal damage of the surrounding tissues, which was more suitable for the practical application of ophthalmology due to the complex structure of the eyeball. Moreover, superior biocompatibility was approved by the preliminary toxicity investigations, including low cytotoxicity, negligible damage to major organs, and stable intraocular pressure. Conclusions: Our studies of nanosystem provide a promising synergic therapeutic strategy for postcataract endophthalmitis treatment with favorable prognosis and promise in clinical translations.

Silver-decorated mesostructured cellular silica foams as excellent antibacterial hemostatic agents for rapid and effective treatment of hemorrhage.

Uncontrolled bleeding, such as deep, narrow or irregular wound hemorrhage, has been a major cause of death in peacetime and wartime. Besides, traditional hemostatic agents are lack of antibacterial properties, which could not provide effective protection on open wound. In this paper, a novel antibacterial hemostatic agent composed of mesostructured cellular silica foams (MCF) decorated with silver ions (MCF-Ag) was synthesized by hydrothermal method. Hemorrhage wound infected with Escherichia coli was applied to evaluate its antibacterial and hemostatic performance both in vitro and in vivo. Both MCF and MCF-Ag showed excellent hemostasis in vitro and in vivo. The MCF-Ag demonstrated significant antibacterial effect. By contrast, no obvious antibacterial effect was observed from the MCF. The above results demonstrate that the MCF-Ag is an excellent antibacterial hemostatic agent with splendid water absorption and antibacterial capacity.

Facile, one-pot biosynthesis and characterization of iron, copper and silver nanoparticles using Syzygium cumini leaf extract: As an effective antimicrobial and aflatoxin B1 adsorption agents.

In this study, a facile, ecological and economical green method is described for the fabrication of iron (Fe), copper (Cu) and silver (Ag) nanoparticles (NPs) from the extract of Syzygium cumini leaves. The obtained metal NPs were categorized using UV/Vis, SEM, TEM, FTIR and EDX-ray spectroscopy techniques. The Fe-, Cu- and Ag-NPs were crystalline, spherical and size ranged from 40-52, 28-35 and 11-19 nm, respectively. The Ag-NPs showed excellent antimicrobial activities against methicillin- and vancomycin-resistance Staphylococcus aureus bacterial strains and Aspergillus flavus and A. parasiticus fungal species. Furthermore, the aflatoxins (AFs) production was also significantly inhibited when compared with the Fe- and Cu-NPs. In contrast, the adsorption results of NPs with aflatoxin B1 (AFB1) were observed as following order Fe->Cu->Ag-NPs. The Langmuir isotherm model well described the equilibrium data by the sorption capacity of Fe-NPs (105.3 ng mg-1), Cu-NPs (88.5 ng mg-1) and Ag-NPs (81.7 ng mg-1). The adsorption was found feasible, endothermic and follow the pseudo-second order kinetic model as revealed by the thermodynamic and kinetic studies. The present findings suggests that the green synthesis of metal NPs is a simple, sustainable, non-toxic, economical and energy-effective as compared to the others conventional approaches. In addition, synthesized metal NPs might be a promising AFs adsorbent for the detoxification of AFB1 in human and animal food/feed.

Suppressing growth, migration, and invasion of human hepatocellular carcinoma HepG2 cells by Catharanthus roseus­silver nanoparticles.

Application of silver nanoparticles serves as a new approach in cancer treatment due to its unique features. Biosynthesis of silver nanoparticles using plant is advantageous since they are easily accessible, nontoxic and produce quicker reaction compared to other methods. To evaluate the cytotoxicity, mechanism of cell death and DNA damage of biosynthesized Catharanthus roseus-silver nanoparticles on human liver cancer (HepG2) cells. The antiproliferative activity of Catharanthus roseus­silver nanoparticles was measured using MTT assay. The cytotoxic effects were further evaluated by measuring nitric oxide and reactive oxygen species (ROS). The mechanism of cell death was determined by annexin-FITC/propidium iodide, mitochondrial membrane potential (MMP) and cell cycle assays. The assessment of DNA damage was evaluated using Comet assay method. The uptake of the nanoparticles were evaluated by Transmission Electron Microscopy (TEM). Catharanthus roseus­silver nanoparticles has inhibited the proliferation of HepG2 cells in a time-dependent manner with a median IC50 value of 3.871 ± 0.18 µg/mL. The concentration of nitrite and ROS were significantly higher than control. The cell death was due to apoptosis associated with MMP loss, cell cycle arrest, and extensive DNA damage. TEM analysis indicated the presence of free nanoparticles and endosomes containing the nanoparticles. The findings show that Catharanthus roseus­silver nanoparticles have produced cytotoxic effects on HepG2 cells and thus may have a potential to be used as an anticancer treatment, particularly for hepatocellular carcinoma.

Targeted Delivery of Colloidal Silver for MCF-7 Breast Cancer Treatment.

BACKGROUND: Amongst various cancer diseases, breast cancer is frequently diagnosed malignancy in women. Existing treatments are inadequate, painful and toxic. New ways of treatments need to be explored. METHODS: The present work proposes preparation and targeted delivery of a formulation, F-1, for MCF-7 breast cancer treatment. The formulation, colloidal silver (0.76 ppm), was prepared by electrolytic deposition technique and multi surface coatings. Black tea extract (2.25%v/v) was used as a capping agent to tune the morphology of silver nanoparticle and potato extract (6.25%v/v) as a functionalizing agent for targeting MCF-7 breast cancer site. RESULTS: Characterization results show highly pure spherical silver nanoparticles with an average particle size of 15nm. The shift of peaks in the FTIR spectra of formulation confirms the interaction between nanoparticles and extracts. The UV-visible peak was obtained at 525nm, a typical characteristic of silver nanoparticles. In-vivo; anti-cancer study of formulation gave a moderate therapeutic effect in Non-Obese Diabetic Severe Combined Immune Deficiency (NOD-SCID) mice. CONCLUSION: It is observed that tumor volumes obtained in the case of Formulation-1 were moderately inhibited from days 5 to 9. However, one of the mice in the Formulation-1 group inhibited tumor volume to 1.52 cc similar to one of the mice of positive control group (Adriamycin 1.42cc).

Immobilization of novel inorganic nano-complexes onto MWCNT nanomaterials as a novel adsorbent and anti-inflammatory therapy in an induced model of rheumatoid arthritis.

Novel supported inorganic metal nano-complexes of Ag(I) and Co(II) derived from 4-amino-N-(4-methylpyrimidin-2-yl) benzene sulfonamide (SulMer) were synthesized using olive leaf extract as a reducing agent with grinding and microwave methods. The prepared samples were denoted as Comp1-6. The surface morphologies of the synthesized nanomaterials were analyzed using C, H, N, S analysis, Fourier-transform infrared spectroscopy, UV- visible spectroscopy, proton and carbon nuclear magnetic resonance, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and x-ray powder diffraction (XRD) analysis. The data revealed that all the synthesized complexes exhibited a 1:1 metal-to-ligand ratio with a coordination number of 4 or 6. The mean particle size of the nanomaterial samples was 25-35 nm. The XRD patterns indicated a crystalline nature for the complexes. The supported inorganic metal nano-complexes displayed good activity in the adsorptive removal of Direct Red 81 (DR-81) from aqueous solutions. In addition, the effect of the supported metal nano-complexes on the immune system was studied as well as how these anti-inflammatory compounds could be used to treat many autoimmune diseases, most notably rheumatoid arthritis. An experimental model for arthritis can be induced using complete Freund's adjuvant. It was shown that the supported complex offers several advantages such stability, eco-friendliness, simple experimental conditions, short reaction times, and easy work- up.

Green synthesis and characterization of silver nanoparticles from Moringa oleifera flower and assessment of antimicrobial and sensing properties.

The present study aimed to explore the biosynthesis and characterization of silver nanoparticles (AgNPs) from Moringa oleifera flower (MOF) extract and its antimicrobial and sensing properties. The prepared AgNPs were characterized by Transmission Electron Microscopy (TEM), UV-visible spectral analysis (UV-vis), X-Ray Diffraction (X-RD), Energy Dispersive Spectroscopy (EDS), and Fourier Infra-Red Spectroscopy (FTIR) respectively. Antimicrobial and sensing properties of the prepared nanoparticles were also determined. Face-Centered Cubic (FCC) lattice of the AgNPs was observed in X-RD pattern. FTIR measurement evidenced the band pattern at 686, 1653, 2062 and 3456 cm-1 proved the presence of proteins and phenolic components in MOF responsible for reduction. TEM analysis indicated the formation of monodispersed spherical particles with 8 nm. UV-vis of the prepared AgNPs authenticated the surface plasmon resonance (SPR) at 429 nm and stable for six months. AgNPs have produced highest zone of inhibition (ZOI) of 17 mm and 29 mm against Klebsiella pneumoniae and Staphylococcus aureus respectively. In addition, the AgNPs effectively detected the presence of Copper ions from 1 mM to 12 mM concentrations. Copper sensitivity of these biosynthesized nanoparticles was carried out by optical sensor based SPR. Thus the obtained antimicrobial and optical properties, suggested the use of obtained AgNPs in water purification.

Local Treatment of Local Staphylococcal Infection with Complex Preparations Based on Metal Nanoparticles in the Experiment.

Antibacterial activity of powdered preparations based on copper and silver nanoparticles was compared with activity of the reference preparation Baneocin on the model of local staphylococcal infection in white rats. The developed preparations exhibited pronounced antibacterial activity against methicillin-resistant S. epidermidis strains in vivo significantly (p<0.001) exceeding that of Baneocin, reduced microbial contamination of the wound on day 5 of study by 2 lg and more in comparison with bacterial load before treatment, and provided effective decontamination of the wound within 7-10 days.

Daptomycin and AgNP co-loaded rGO nanocomposites for specific treatment of Gram-positive bacterial infection in vitro and in vivo.

In order to improve the stability of AgNPs and decrease the dosage of Daptomycin for killing bacteria, a reduced graphene oxide (rGO) was used for simultaneously anchoring AgNPs and Daptomycin to prepare rGO@Ag@Dap nanocomposites. In vitro experiments showed that the nanocomposites can efficiently kill four kinds of pathogenic bacteria, especially two kinds of Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) through damaging cell integrity, producing ROS, decreasing ATP and GSH and disrupting bacterial metabolism. Against Gram-positive bacteria, the rGO@Ag@Dap nanocomposites showed a cooperative antibacterial effect. Moreover, in vivo experiments showed that rGO@Ag@Dap can improve the healing of wounds infected with bacteria by efficiently killing the bacteria on the wounds and further promoting skin regeneration and dense collagen deposition. In summary, the above results suggest that the cooperative function of AgNPs with Daptomycin can significantly improve antibacterial efficiency against infectious diseases caused by bacteria, especially for therapies made ineffective due to the drug resistance of pathogenic bacteria.

Novel lavender oil and silver nanoparticles simultaneously loaded onto polyurethane nanofibers for wound-healing applications.

Synthetic polymers, especially those with biocompatible and biodegradable characteristics, may offer effective alternatives for the treatment of severe wounds and burn injuries. Ideally, the scaffold material should induce as little pain as possible, enable quick healing, and direct the growth of defect-free epidermal cells. The best material with this multifunctionality, such as self-healing dressings, should be hydrophilic and have uninterrupted and direct contact with the damaged tissue. In addition, the ideal biomaterial should have some antibacterial properties. In this study, a novel technique was used to fabricate composite electrospun wound-dressing nanofibers composed of polyurethane encasing lavender oil and silver (Ag) nanoparticles (NPs). After electrospinning, the fabricated nanofibers were identified using various techniques, including scanning electron microscopy (SEM) and transmission electron microscopy (TEM). An abundance of Ag NPs in the fibers decreased the diameter of the fibers while increased concentration of the lavender oil increased the diameter. Fourier transform infrared (FTIR) and X-ray diffraction (XRD) studies showed the presence of the lavender oil and Ag NPs in the fiber dressings. The Ag NPs and lavender oil improved the hydrophilicity of the nanofibers and ensured the proliferation of chicken embryo fibroblasts cultured in-vitro on these fiber dressings. The antibacterial efficiency of the nanofiber dressings was investigated using E. coli and S. aureus, which yielded zones of inhibition of 16.2 ±â€¯0.8 and 5.9 ±â€¯0.5 mm, respectively, indicating excellent bactericidal properties of the dressings. The composite nanofiber dressings have great potential to be used as multifunctional wound dressings; offering protection against external agents as well as promoting the regeneration of new tissue.

Exposure of stevia (Stevia rebaudiana B.) to silver nanoparticles in vitro: transport and accumulation.

The impact of nanotechnology in the field of agricultural sciences creates the need to study in greater detail the effect of products offering nanoparticles for application in plant species of agricultural interest. The objective of this study was to determine the response of stevia (Stevia rebaudiana B.) in vitro to different concentrations of AgNPs (silver nanoparticles), as well as to characterize and identify their absorption, translocation and accumulation mechanisms. Nodal segments of stevia grown in MS medium supplemented with AgNPs (0,12.5, 25, 50,100 and 200 mg L-1) were used. After 30 days of in vitro shoot proliferation, the number of shoots per explant, shoot length, chlorophyll content, dry matter content and the metallic silver (Ag) content of the plants were quantified. In addition, characterization, transport and accumulation of silver nanoparticles were performed by microscopic analysis. AgNPs were shown to be present in epidermal stem cells, within vascular bundles and in intermembrane spaces. In leaves, they were observed in ribs and stomata. The current and future use of AgNPs in agricultural sciences opens up the possibility of studying their effects on different plant species.

Silver triethanolamine-loaded PVB/CO films for a potential liquid bandage application.

Many studies have reported that silver has excellent antibacterial properties. However, silver ions can easily react with oxygen to form Ag2O, thus leading to a color change and a reduction in its anti-microbial characteristics. In this study, silver triethanolamine- (ST) loaded PVB/CO solution was prepared as a potential candidate liquid bandage. PVB/CO/ST retained high transparency after exposure to light for 12 months, which allowed convenient inspection of the wound bed without removal of the dressing. The PVB/CO/ST film exhibited favorable properties, such as speed of drying, excellent tensile strength and elongation characteristics and water vapor transmission rate (WVTR). It was comfortable and waterproof, and therefore effective at preventing bacterial invasion, providing effective biosafety. PVB/CO/ST solution-treated wounds exhibited accelerated healing and reduced inflammation in a nude mouse mode. Our data suggested that PVB/CO/ST solution could serve as a promising liquid bandage for treatment of minor trauma.