A bottom-up approach for synthesizing silver nanoparticles (AgNPs-GA) phytomediated by Garcinia atroviridis leaf extract is described. Under optimized conditions, the AgNPs-GA were synthesized at a concentration of 0.1 M silver salt and 10% (w/v) leaf extract, 1:4 mixing ratio of reactants, pH 3, temperature 32 °C and 72 h reaction time. The AgNPs-GA were characterized by various analytical techniques and their size was determined to be 5-30 nm. FTIR spectroscopy indicates the role of phenolic functional groups in the reduction of silver ions into AgNPs-GA and in supporting their subsequent stability. The UV-Visible spectrum showed an absorption peak at 450 nm which reflects the surface plasmon resonance (SPR) of AgNPs-GA and further supports the stability of these biosynthesized nanoparticles. SEM, TEM and XRD diffractogram analyses indicate that AgNPs-GA were spherical and face-centered-cubic in shape. This study also describes the efficacy of biosynthesized AgNPs-GA as anti-proliferative agent against human breast cancer cell lines, MCF-7 and MCF-7/TAMR-1. Our findings indicate that AgNPs-GA possess significant anti-proliferative effects against both the MCF-7 and MCF-7/TAMR-1 cell lines, with inhibitory concentration at 50% (IC50 values) of 2.0 and 34.0 µg/mL, respectively, after 72 h of treatment. An induction of apoptosis was evidenced by flow cytometry using Annexin V-FITC and propidium iodide staining. Therefore, AgNPs-GA exhibited its anti-proliferative activity via apoptosis on MCF-7 and MCF-7/TAMR-1 breast cancer cells in vitro. Taken together, the leaf extract from Garcinia atroviridis was found to be highly capable of producing AgNPs-GA with favourable physicochemical and biological properties.
Green porous and ecofriendly scaffolds have been considered as one of the potent candidates for tissue engineering substitutes. The objective of this study is to investigate the biocompatibility of hydroxyethyl cellulose (HEC)/silver nanoparticles (AgNPs), prepared by the green synthesis method as a potential host material for skin tissue applications. The substrates which contained varied concentrations of AgNO3(0.4%-1.6%) were formed in the presence of HEC, were dissolved in a single step in water. The presence of AgNPs was confirmed visually by the change of color from colorless to dark brown, and was fabricated via freeze-drying technique. The outcomes exhibited significant porosity of >80%, moderate degradation rate, and tremendous value of water absorption up to 1163% in all samples. These scaffolds of HEC/AgNPs were further characterized by SEM, UV-Vis, ATR-FTIR, TGA, and DSC. All scaffolds possessed open interconnected pore size in the range of 50-150μm. The characteristic peaks of Ag in the UV-Vis spectra (417-421nm) revealed the formation of AgNPs in the blend composite. ATR-FTIR curve showed new existing peak, which implies the oxidation of HEC in the cellulose derivatives. The DSC thermogram showed augmentation in Tgwith increased AgNO3concentration. Preliminary studies of cytotoxicity were carried out in vitro by implementation of the hFB cells on the scaffolds. The results substantiated low toxicity of HEC/AgNPs scaffolds, thus exhibiting an ideal characteristic in skin tissue engineering applications.
In this paper, we present the effect of varying humidity levels on the electrical parameters and the multi frequency response of the electrical parameters of an organic-inorganic composite (PEPC+NiPc+Cu2O)-based humidity sensor. Silver thin films (thickness ~200 nm) were primarily deposited on plasma cleaned glass substrates by the physical vapor deposition (PVD) technique. A pair of rectangular silver electrodes was formed by patterning silver film through standard optical lithography technique. An active layer of organic-inorganic composite for humidity sensing was later spun coated to cover the separation between the silver electrodes. The electrical characterization of the sensor was performed as a function of relative humidity levels and frequency of the AC input signal. The sensor showed reversible changes in its capacitance with variations in humidity level. The maximum sensitivity ~31.6 pF/%RH at 100 Hz in capacitive mode of operation has been attained. The aim of this study was to increase the sensitivity of the previously reported humidity sensors using PEPC and NiPc, which has been successfully achieved.
This review (with 99 refs.) summarizes the progress that has been made in colorimetric (i.e. spectrophotometric) determination of organophosphate pesticides (OPPs) using gold and silver nanoparticles (NPs). Following an introduction into the field, a first large section covers the types and functions of organophosphate pesticides. Methods for colorimetric (spectrophotometric) measurements including RGB techniques are discussed next. A further section covers the characteristic features of gold and silver-based NPs. Syntheses and modifications of metal NPs are covered in section 5. This is followed by overviews on enzyme inhibition-based assays, aptamer-based assays and chemical (non-enzymatic) assays, and a discussion of specific features of colorimetric assays. Several Tables are presented that give an overview on the wealth of methods and materials. A concluding section addresses current challenges and discusses potential future trends and opportunities. Graphical abstractSchematic representation of organophosphate pesticide determinations based on aggregation of nanoparticles (particular silver or gold nanoparticles). This leads to a color change which can be determined visually and monitored by a red shift in the absorption spectrum.
Adsorption behaviours of butyl acetate in air have been studied over silver-loaded Y (Si/Al=40) and ZSM-5 (Si/Al=140) zeolites. The silver metal was loaded into the zeolites by ion exchange (IE) and impregnation (IM) methods. The adsorption study was mainly conducted at a gas hourly space velocity (GHSV) of 13,000 h(-1) with the organic concentration of 1000 ppm while the desorption step was carried out at a GHSV of 5000 h(-1). The impregnated silver-loaded adsorbents showed lower uptake capacity and shorter breakthrough time by about 10 min, attributed to changes in the pore characteristics and available surface for adsorption. Silver exchanged Y (AgY(IE)) with lower hydrophobicity showed higher uptake capacity of up to 35%, longer adsorbent service time and easier desorption compared to AgZSM-5(IE). The presence of water vapour in the feed suppressed the butyl acetate adsorption of AgY(IE) by 42% due to the competitive adsorption of water on the surface and the effect was more pronounced at lower GHSV. Conversely, the adsorption capacity of AgZSM-5(IE) was minimally affected, attributed to the higher hydrophobicity of the material. A mathematical model is proposed to simulate the adsorption behaviour of butyl acetate over AgY(IE) and AgZSM-5(IE). The model parameters were successfully evaluated and used to accurately predict the breakthrough curves under various process conditions with root square mean errors of between 0.05 and 0.07.
This Research Article reports an unusually high efficiency heterogeneous photodegradation of methyl orange (MO) in the presence of Ag nanoparticle-loaded ZnO quasi-nanotube or nanoreactor (A-ZNRs) nanocatalyst grown on FTO substrate. In typical process, photodegradation efficiency of as high as 21.6% per μg per Watts of used catalyst and UV power can be normally obtained within only a 60-min reaction time from this system, which is 10(3) order higher than the reported results. This is equivalent to the turnover frequency of 360 mol mol(-1) h(-1). High-density hexagonal A-ZNRs catalysts were grown directly on FTO substrate via a seed-mediated microwave-assisted hydrolysis growth process utilizing Ag nanoparticle of approximately 3 nm in size as nanoseed and mixture aqueous solution of Zn(NO3)·6H2O, hexamethylenetetramine (HMT), and AgNO3 as the growth solution. A-ZNRs adopts hexagonal cross-section morphology with the inner surface of the reactor characterized by a rough and rugged structure. Transmission electron microscopy imaging shows the Ag nanoparticle grows interstitially in the ZnO nanoreactor structure. The high photocatalytic property of the A-ZNRs is associated with the highly active of inner side's surface of A-ZNRs and the oxidizing effect of Ag nanoparticle. The growth mechanism as well as the mechanism of the enhanced-photocatalytic performance of the A-ZNRs will be discussed.
An incredible amount of joss fly ash is produced from the burning of Chinese holy joss paper; thus, an excellent method of recycling joss fly ash waste to extract aluminosilicate nanocomposites is explored. The present research aims to introduce a novel method to recycle joss fly ash through a simple and straightforward experimental procedure involving acidic and alkaline treatments. The synthesized aluminosilicate nanocomposite was characterized to justify its structural and physiochemical characteristics. A morphological analysis was performed with field-emission transmission electron microscopy, and scanning electron microscopy revealed the size of the aluminosilicate nanocomposite to be ~25 nm, while also confirming a uniformly spherical-shaped nanostructure. The elemental composition was measured by energy dispersive spectroscopy and revealed the Si to Al ratio to be 13.24 to 7.96, showing the high purity of the extracted nanocomposite. The roughness and particle distribution were analyzed using atomic force microscopy and a zeta analysis. X-ray diffraction patterns showed a synthesis of faceted and cubic aluminosilicate crystals in the nanocomposites. The presence of silica and aluminum was further proven by X-ray photoelectron spectroscopy, and the functional groups were recognized through Fourier transform infrared spectroscopy. The thermal capacity of the nanocomposite was examined by a thermogravimetric analysis. In addition, the research suggested the promising application of aluminosilicate nanocomposites as drug carriers. The above was justified by an enzyme-linked apta-sorbent assay, which claimed that the limit of the aptasensing aluminosilicate-conjugated ampicillin was two-fold higher than that in the absence of the nanocomposite. The drug delivery property was further justified through an antibacterial analysis against Escherichia coli (gram-negative) and Bacillus subtilis (gram-positive).
In this present investigation, AgNPs were green synthesised using Coriandrum sativum leaf extract. The physicochemical properties of AgNPs were characterised using UV-visible spectrophotometer, field emission scanning microscopy/energy dispersive X-ray (FESEM/EDX), Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) analysis. Further, in vitro anti-acne, anti-dandruff and anti-breast cancer efficacy of green synthesised AgNPs were assessed against Propionibacterium acnes MTCC 1951, Malassezia furfur MTCC 1374 and human breast adenocarcinoma (MCF-7) cell line, respectively. The flavonoids present in the plant extract were responsible for the AgNPs synthesis. The green synthesised nanoparticles size was found to be ≈37nm. The BET analysis result shows that the surface area of the synthesised AgNPs was found to be 33.72m(2)g(-1). The minimal inhibitory concentration (MIC) of AgNPs for acne causative agent P. acnes and dandruff causative agent M. furfur was found to be at 3.1 and 25μgmL(-1), respectively. The half maximal inhibitory concentration (IC50) value of the AgNPs for MCF-7 cells was calculated as 30.5μgmL(-1) and complete inhibition was observed at a concentration of 100μgmL(-1). Finally, our results proved that green synthesised AgNPs using C. sativum have great potential in biomedical applications such as anti-acne, anti-dandruff and anti-breast cancer treatment.
Angiogenesis, which is required for physiological events, plays a crucial role in several pathological conditions, such as tumor growth and metastasis. The use of plant extracts is a cost effective and eco-friendly way to synthesize nanoparticles. In the present study, we investigated the anti-angiogenesis properties of silver nanoparticles synthesized using Saliva officinalis extract on chick chorioalantoic membrane. The production of nanoparticles was confirmed by the color change from yellow to brown observed after approximately 3 h at 37 °C. Then, the nanoparticles were characterized by UV-visible spectroscopy, FTIR, and TEM. The UV-visible spectroscopy results showed that the surface plasmon resonance band for AgNPs was around 430 nm. The intensity of the AgNP-specific absorption peak improved with an increase of 0.5 mL of extract into 10 mL of AgNO3 (2.5 mM). The FTIR results showed good interaction between the plant extracts and AgNPs. The TEM images of the samples revealed that the NPs varied in morphology and size from 1 to 40 nm; the average was recorded at 16.5 ± 1.2 nm. Forty Ross fertilized eggs were divided into four groups; the control and three experimental groups. On the 8th day, gelatin sponges containing albumin were placed on the chorioalantoic membrane and soaked with different concentrations of NPs. On the 12th day, all the cases were photographed using a photostereomicroscope. The number and the lengths of the vessels were measured using Image J software. The crown rump (CR) and weight of the embryo were also recorded. Then the hemoglobin content was measured using Drabkin's reagent kit for quantification of the blood vessel formation. According to the data analysis, the number and length of the blood vessels, as well as the CR and weight of the embryos reduced significantly compared to the control (p < 0.05), dose dependently. The total hemoglobin was quantified as an indicator of the blood vessel formation. The hemoglobin content in the treated samples with AgNPs decreased, which showed its inhibitory effect on angiogenesis.
Staphylococcus aureus is a Gram-positive pathogen that causes potentially life-threatening nosocomial- and community-acquired infections, such as osteomyelitis and endocarditis. Staphylococcus aureus has the ability to form multicellular, surface-adherent communities called biofilms, which enables it to survive in various sources of stress, including antibiotics, nutrient limitations, heat shock, and immune responses. Biofilm-forming capacity is now recognized as an important virulence determinant in the development of staphylococcal device-related infections. In light of the projected increase in the numbers of elderly patients who will require semi-permanent indwelling medical devices such as artificial knees and hips, we can anticipate an expanded need for new agents and treatment options to manage biofilm-associated infections in an expanding at-risk population. With better understanding of staphylococcal biofilm formation and growth, novel strategies that target biofilm-associated infections caused by S. aureus have recently been described and seem promising as future anti-biofilm therapies.
This paper describes the extracellular synthesis of silver nanoparticles from waste part of lychee fruit (peel) and their conjugation with selected antibiotics (amoxicillin, cefixim, and streptomycin). FTIR studies revealed the reduction of metallic silver and stabilization of silver nanoparticles and their conjugates due to the presence of CO (carboxyl), OH (hydroxyl) and CH (alkanes) groups. The size of conjugated nanoparticles varied ranging from 3 to 10 nm as shown by XRD. TEM image revealed the spherical shape of biosynthesized silver nanoparticles. Conjugates of amoxicillin and cefixim showed highest antibacterial activity (147.43 and 107.95%, respectively) against Gram-negative bacteria i.e. Alcaligenes faecalis in comparison with their control counterparts. The highest reduction in MIC was noted against Gram-positive strains i.e. Enterococcus faecium (75%) and Microbacterium oxydans (75%) for amoxicillin conjugates. Anova two factor followed by two-tailed t test showed non-significant results both in case of cell leakage and protein estimation between nanoparticles and conjugates of amoxicillin, cefixime and streptomycin. In case of MDA release, non-significant difference among the test samples against the selected strains. Our study found green-synthesized silver nanoparticles as effective antibacterial bullet against both Gram positive and Gram negative bacteria, but they showed a more promising effect on conjugation with selected antibiotics against Gram negative type.
Nanomedicine is now being introduced as a recent trend in the field of medicine. It has been documented that metal nanoparticles have antimicrobial effects for bacteria, fungi and viruses. Recent advances in technology has revived the use of silver nanoparticles in the medical field; treatment, diagnosis, monitoring and control of disease. It has been used since ancient times for treating wide range of illnesses. Bacterial cells adheres to surfaces and develop structures known as biofilms. These structures are natural survival strategy of the bacteria to invade the host. They are more tolerant to commonly used antimicrobial agents, thus being more difficult to be controlled. This leads to increase in severity of infection. In this study, we have investigated the effect of silver nanoparticles in the formation of biofilm in multidrug resistant strains of Pseudomonas aeruginosa. Observation showed that biofilm formation occurred at bacterial concentration of 10(6) cfu/ml for the sensitive strain of P. aeruginosa while in the resistant strain, the biofilm was evident at bacterial concentration of about 10(3) cfu/ml. The biofilm were then tested against various concentrations of silver nanoparticles to determine the inhibitory effect of the silver nanoparticles. In the sensitive strain, 20 μg/ml of silver nanoparticles inhibited the growth optimally at bacterial concentration of 10(4) cfu/ml with an inhibition rate of 67%. Similarly, silver nanoparticles inhibited the formation of biofilm in the resistant strain at an optimal bacterial concentration of 10(5) cfu/ml with an inhibition rate of 56%. Thus, silver nanoparticles could be used as a potential alternative therapy to reduce severity of disease due to P. aeruginosa infections.
Acanthamoeba castellanii belonging to the T4 genotype may cause a fatal brain infection known as granulomatous amoebic encephalitis, and the vision-threatening eye infection Acanthamoeba keratitis. The aim of this study was to evaluate the antiamoebic effects of three clinically available antidiabetic drugs, Glimepiride, Vildagliptin and Repaglinide, against A. castellanii belonging to the T4 genotype. Furthermore, we attempted to conjugate these drugs with silver nanoparticles (AgNPs) to enhance their antiamoebic effects. Amoebicidal, encystation, excystation, and host cell cytotoxicity assays were performed to unravel any antiacanthamoebic effects. Vildagliptin conjugated silver nanoparticles (Vgt-AgNPs) characterized by spectroscopic techniques and atomic force microscopy were synthesized. All three drugs showed antiamoebic effects against A. castellanii and significantly blocked the encystation. These drugs also showed significant cysticidal effects and reduced host cell cytotoxicity caused by A. castellanii. Moreover, Vildagliptin-coated silver nanoparticles were successfully synthesized and are shown to enhance its antiacanthamoebic potency at significantly reduced concentration. The repurposed application of the tested antidiabetic drugs and their nanoparticles against free-living amoeba such as Acanthamoeba castellanii described here is a novel outcome that holds tremendous potential for future applications against devastating infection.
The aim of this study was to evaluate in vitro the apical sealing ability of cold lateral and system B root filling techniques using dye penetration. Eighty-six extracted single-rooted human teeth were prepared and randomly divided into two experimental groups to be obturated by cold lateral condensation (n = 33) and system B (n = 33). The remaining 20 teeth served as positive and negative controls. The roots were embedded for 72 h in methylene blue dye solution and sectioned transversely for dye penetration evaluation using stereomicroscope. The results of this study showed that cold lateral condensation leaked significantly more (P < 0.001) than system B technique.
An experimental nanosilver-coated low-density polyethylene (LDPE) food packaging was incubated with food simulants using a conventional oven and tested for migration according to European Commission Regulation No. 10/2011. The commercial LDPE films were coated using a layer-by-layer (LbL) technique and three levels of silver (Ag) precursor concentration (0.5%, 2% and 5% silver nitrate (AgNO3), respectively) were used to attach antimicrobial Ag. The experimental migration study conditions (time, temperature and food simulant) under conventional oven heating (10 days at 60°C, 2 h at 70°C, 2 h at 60°C or 10 days at 70°C) were chosen to simulate the worst-case storage period of over 6 months. In addition, migration was quantified under microwave heating. The total Ag migrant levels in the food simulants were quantified by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Mean migration levels obtained by ICP-AES for oven heating were in the range 0.01-1.75 mg l(-1). Migration observed for microwave heating was found to be significantly higher when compared with oven heating for similar temperatures (100°C) and identical exposure times (2 min). In each of the packaging materials and food simulants tested, the presence of nanoparticles (NPs) was confirmed by scanning electron microscopy (SEM). On inspection of the migration observed under conventional oven heating, an important finding was the significant reduction in migration resulting from the increased Ag precursor concentration used to attach Ag on the LDPE LbL-coated films. This observation merits further investigation into the LbL coating process used, as it suggests potential for process modifications to reduce migration. In turn, any reduction in NP migration below regulatory limits could greatly support the antimicrobial silver nanoparticle (AgNP)-LDPE LbL-coated films being used as a food packaging material.
Sorbent materials based on a hydrazone Schiff base compound, C(14)H(11)BrN(4)O(4), were prepared either by immobilizing the ligand into sol-gel (SG1) or bonding to silica (SG2). The sorbent materials were characterized by FT-IR, EDX, SEM, TEM, and TGA. The sorption characteristics of a matrix of eight transition metal ions (Ag(+), Cu(2+), Co(2+), Ni(2+), Fe(3+), Pb(2+), Zn(2+), and Mn(2+)) using batch method were studied. Several key parameters that affected the extraction efficiency such as pH, contact time, metal ions concentration, and gel size (for SGl) were investigated and optimized. Under the optimized conditions, the physically immobilized hydrazone sorbent (SG1) exhibits highest selectivity towards Ag(+) ions, while the chemically bonded hydrazone sorbent (SG2) exhibits high extraction for all metal ions tested. However, for practical applications such as the removal and preconcentration of Ag(+), the physically immobilized sorbent (SG1) is preferred.
In this research, a milk thistle seed extract (MTSE)-rich medium was used as a capping and reducing agent for the one-pot biosynthesis of ZnO/Ag (5 wt%) nanostructure. The sample was systematically characterized through various techniques and its strong biomolecule‒metal interface structure was supported by the results. The efficacy of the derived nanostructure (MTSE/ZnO/Ag) was evaluated in vivo on the basis of its therapeutic effects on the main complications of Type 1 diabetes (hyperglycemia, hyperlipidemia, and insulin deficiency). For this purpose, the changes in the plasma values of fasting blood glucose, total cholesterol, total triglyceride, high-density lipoprotein cholesterol, and insulin in alloxan-diabetic Wistar male rats were compared with those in healthy and untreated diabetic controls after a treatment period of 16 days. The antidiabetic results of MTSE/ZnO/Ag were compared with those obtained from pristine ZnO, MTSE, and insulin therapies. The health conditions of the rats with Type 1 diabetes were significantly enhanced after treatment with MTSE/ZnO/Ag (p
Nanotechnology is gaining momentum due to its ability to transform metals into nanoparticles. The synthesis, characterization, and applications of biologically synthesized nanomaterials have become an important branch of nanotechnology. Plant extracts are a cost-effective, ecologically friendly, and efficient alternative for the large-scale synthesis of nanoparticles. In this study, silver nanoparticles (AgNps) were synthesized using Rhinacanthus nasutus leaf extract. After exposing the silver ions to the leaf extract, the rapid reduction of silver ions led to the formation of AgNps in solution. The synthesis was confirmed by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy. The in vitro antimicrobial activity of the AgNps synthesized using R. nasutus leaf extract was investigated against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia, Escherichia coli, Aspergillus niger, and Aspergillus flavus using a disc diffusion method. The AgNps showed potential activity against all of the bacterial strains and fungal colonies, indicating that R. nasutus has the potential to be used in the development of value-added products in the biomedical and nanotechnology-based industries.
In the current study, facile synthesis of carboxymethyl cellulose (CMC) and sodium alginate capped silver nanoparticles (AgNPs) was examined using microwave radiation and aniline as a reducing agent. The biopolymer matrix embedded nanoparticles were synthesized under various experimental conditions using different concentrations of biopolymer (0.5, 1, 1.5, 2%), volumes of reducing agent (50, 100, 150 μL), and duration of heat treatment (30 s to 240 s). The synthesized nanoparticles were analyzed by scanning electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for identification of AgNPs synthesis, crystal nature, shape, size, and type of capping action. In addition, the significant antibacterial efficacy and antibiofilm activity of biopolymer capped AgNPs were demonstrated against different bacterial strains, Staphylococcus aureus MTCC 740 and Escherichia coli MTCC 9492. These results confirmed the potential for production of biopolymer capped AgNPs grown under microwave irradiation, which can be used for industrial and biomedical applications.
In this work, two natural sources, including pomegranate peel extract and cochineal dye were employed for the synthesis of silver nanoparticles. The natural silver complex from pomegranate peel extract resulted in nano-sized structures through solution-phase method, but this method was not efficient for cochineal dye-silver precursor and the as-formed products were highly agglomerated. Therefore, an alternative facile solid-state approach was investigated as for both natural precursors and the results showed successful production of well-dispersed nanoparticles with narrow size distribution for cochineal dye-silver precursor. The products were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray microanalysis (EDX), and Transmission Electron Microscopy (TEM).