Green synthesis and characterizations of Nickel oxide nanoparticles using leaf extract of Rhamnus virgata and their potential biological applications

In the present report, Nickel oxide nanoparticles (NiONPs) were synthesized using Rhamnus virgata (Roxb.) (Family: Rhamnaceae) as a potential stabilizing, reducing and chelating agent. The formation, morphology, structure and other physicochemical properties of resulting NiONPs were characterized by Ultra violet spectroscopy, X‐ray diffraction (XRD), Fourier Transform Infrared analysis (FTIR), Scanning electron microscopy (SEM), Energy‐dispersive‐spectroscopy (EDS), Transmission electron microscopy (TEM), Raman spectroscopy and dynamic light scattering (DLS). Detailed in vitro biological activities revealed significant therapeutic potential for NiONPs. The antimicrobial efficacy of biogenic NiONPs was demonstrated against five different gram positive and gram negative bacterial strains. Klebsiella pneumoniae and Pseudomonas aeruginosa (MIC: 125 μg/mL) were found to be the least susceptible and Bacillus subtilis (MIC: 31.25 μg/mL) was found to be the most susceptible strain to NiONPs. Biogenic NiONPs were reported to be highly potent against HepG2 cells (IC₅₀: 29.68 μg/ml). Moderate antileishmanial activity against Leishmania tropica (KMH₂₃) promastigotes (IC₅₀: 10.62 μg/ml) and amastigotes (IC₅₀: 27.58 μg/ml) cultures are reported. The cytotoxic activity was studied using brine shrimps and their IC₅₀ value was recorded as 43.73 μg/ml. For toxicological assessment, NiONPs were found compatible towards human RBCs (IC₅₀: > 200 μg/ml) and macrophages (IC₅₀: > 200 μg/ml), deeming particles safe for various applications in nanomedicines. Moderate antioxidant activities: total antioxidant capacity (TAC) (51.43%), 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) activity (70.36%) and total reducing power (TRP) (45%) are reported for NiONPs. In addition, protein kinase and alpha amylase inhibition assays were also performed. Our results concluded that Rhamnus virgata synthesized NiONPs could find important biomedical applications with low cytotoxicity to normal cells.     

Green synthesis of silver nanoparticles using Thymus kotschyanus extract and evaluation of their antioxidant,antibacterial and cytotoxic effects

Present study used ecofriendly, cost efficient and easy method for synthesis of silver nanoparticles (Ag NPs) at the room temperature by Thymus Kotschyanus extract as reducing and capping agent. Various analytical technique including UV–Vis absorption spectroscopy determined presence of Ag NPs in the solution, the functional groups of Thymus Kotschyanus extract in the reduction and capping process of Ag NPs are approved by FT‐IR, crystallinity with the fcc plane approved from the X‐ray diffraction (XRD) pattern, energy dispersive spectroscopy (EDS) determined existence of elements in the sample, surface morphology, diverse shapes and size of present Ag NPs were showed by using scanning electron microscopy (SEM), atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM). Beginning and end destroy temperature of present silver nanoparticles were determined by thermal gravimetric spectroscopy (TGA). In addition, antibacterial, antioxidant and cytotoxicity properties of Ag NPs were studied. Agar disk and agar well diffusion are the methods to determined antibacterial properties of synthesized Ag NPs. Also MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) were recognized by macro broth dilution assay. DPPH free radical scavenging assay was used for antioxidant property and compare to butylated hydroxytoluene (BHT) as standard antioxidant that showed high antioxidant activity more than BHT. Synthesized Ag NPs have great cell viability in a dose depended manner and demonstrate that this method for synthesis silver nanoparticles provided nontoxic. The average diameter of synthesized Ag NPs was about 50–60 nm.     

Green biosynthesis of gold nanoparticles using Croton sparsiflorus leaves extract and evaluation of UV protection,antibacterial and anticancer applications

Our study reports greener synthesis of gold nanoparticles (AuNPs) tethered to the extract of Croton sparsiflorus and in vitro evaluation of UV-protection, antibacterial and anticancer activities. Sophisticated instrumental analytical techniques such as UV–vis spectrophotometer, FT-IR, XRD, FE-SEM, and TEM were employed for the existence and confirmation of the nanoparticles. FT-IR and HPLC analysis were executed in the identification of the plausible functional groups implicated in the reduction of gold ions to AuNPs. UV protection property and antibacterial action of AuNPs-coated cotton fabric were also presented. Moreover, in vitro anticancer evaluation against HepG2 cell line was conducted by MTT assay for Croton sparsiflorus extract derived AuNPs in different concentrations (50 to 150 μg/ml). Thus, the results of this work revealed that greener synthesized AuNPs exhibited good therapeutic applications as UV-protection, antibacterial and anticancer agents.     

Phytofabrication of silver nanoparticles from Limonia acidissima leaf extract and their antimicrobial,antioxidant and its anticancer prophecy

Green synthesis of nanoparticles by eco-friendly methods is a recent technique which draws the attention of researchers because of the reward over many conventional chemical methods. The present work focuses on aqueous Limonia acidissima leaf extract in synthesizing silver nanoparticles and its applications in a simple way. The silver nanoparticles formed were characterized by Infrared, Ultra violet-visible, X-ray diffraction, transmission electron microscopic, and atomic force microscopic techniques. The powder X-ray diffraction studies and transmission electron microscopic images reveal that the silver nanoparticles synthesized were approximately 10–40 nm and have a spherical structure. The nanoparticles were assayed for their antibacterial, antifungal and antioxidant activity. The antimicrobial studies for the silver nanoparticles show a maximum zone of inhibition of 8.8 mm for Bacillus subtilis bacteria and 8.5 mm for Candida albicans fungi at 3 and 1 μg/mL respectively. In-silico ADMET studies reveal that the toxicity, bioactivity, pharmacokinetics and drug-likeness properties of Limonia acidissima leaf extract is good. The molecular docking studies show that the microbial activity is high for Bacillus subtilis and Candida albicans showing the coincidence of the in silico and in vitro studies as expected. The free radical scavenging activity of nanoparticles is 80 for 100 μg/mL. The 50% of inhibition of silver nanoparticles against human breast cancer cell lines is 18 μg/mL. It is evident that silver nanoparticles would be helpful in treating cancer cell lines and have great perspectives in the biomedical sector.     

Green and one‐pot surface coating of iron oxide magnetic nanoparticles with natural amino acids and biocompatibility investigation

We report the synthesis of iron oxide magnetic nanoparticles (IONPs) coated with various natural amino acids (AAs) using a one‐pot reaction in an aqueous medium. Several AAs, which contained hydrophilic and hydrophobic groups, were selected to study their effects on size, morphology and toxicity of IONPs. Functionalized IONPs were characterized using X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, and scanning and transmission electron microscopies. Furthermore, vibrating sample magnetometry analysis shows these nanoparticles have excellent magnetic properties. Cellular toxicity of IONPs was also investigated on HFF2 cell lines. The AA‐coated IONPs are non‐toxic and biocompatible. Natural AA‐coated IONPs show a potential for their development in in vitro and in vivo biomedical fields due to their non‐toxicity, good ζ‐potential and related small size and narrow size distribution.     

Pistacia atlantica leaf extract mediated synthesis of silver nanoparticles and their antioxidant,cytotoxicity, and antibacterial effects under in vitro condition

Recently, researchers have investigated the therapeutical properties of metal nanoparticles especially silver nanoparticles in vitro and in vivo conditions. The aim of the experiment was green synthesis and chemical characterization of silver nanoparticles from aqueous extract of Pistacia atlantica leaf (Ag NPs) and evaluation of their cytotoxicity, antioxidant, and antibacterial effects under in vitro condition. Ag NPs were spherical with a size range of 40-60 nm and characterized using various analysis techniques including UV–Vis absorption spectroscopy to determine the presence of Ag NP in the solution. We studied functional groups of Pistacia atlantica extract in the reduction and capping process of Ag NP by FT-IR, crystallinity and FCC planes by XRD pattern, elemental analysis of the sample by EDS, and surface morphology, shapes, and size of Ag NPs by SEM, AFM, and TEM. Destroy initiation and termination temperatures of the Ag NPs were determined by TGA. DPPH free radical scavenging test was done to evaluate the antioxidant potentials, which indicated similar antioxidant potentials for Ag NPs and butylated hydroxytoluene. The synthesized Ag NPs had great cell viability dose-dependently and indicated this method was nontoxic. Agar diffusion tests were done to determine the antibacterial characteristic. Ag NPs revealed similar antibacterial property to the standard antibiotic. Also, Ag NPs prevented the growth of all bacteria at 1-7 μg/ml concentrations and removed them at 3-15 μg/ml concentrations. Finally, synthesized Ag NPs revealed non-cytotoxicity, antioxidant and antibacterial activities in a dose-depended manner.     

Citrus sinensis leaf aqueous extract green-synthesized silver nanoparticles: Characterization and cytotoxicity,antioxidant, and anti-human lung carcinoma effects

The present work demonstrates the synthesis of Ag nanoparticles (Ag NPs) by using aqueous extract of Citrus sinensis as green reductant and capping agent without any toxic reagent. Physicochemical characteristics of the said nanoparticles were elucidated by field emission scanning electron microscopy (FESEM), fourier transform infrared spectroscopy (FTIR), and ultraviolet–visible spectroscopy (UV-Vids) techniques. The biogenic Ag NPs are uniformly globular. The Ag NPs has been explored biologically in the anticancer and antioxidant assays. In the cellular and molecular part of the recent study, the treated cells with Ag NPs were assessed by MTT assay for 48 h about the cytotoxicity and anti-human lung carcinoma properties on normal (HUVEC) and lung carcinoma cell lines i.e. NCI-H661, HLC-1, NCI-H1563, LC-2/ad, NCI-H1299, and PC-14. The viability of malignant lung cell line reduced dose-dependently in the presence of Ag NPs. The IC50 of Ag NPs were 82, 139, 170, 66, 62, and 50 µg/mL against NCI-H661, HLC-1, NCI-H1563, LC-2/ad, NCI-H1299, and PC-14 cell lines, respectively. In the antioxidant test, the IC50 of Ag NPs and vitamin E against 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals were 21 and 15 µg/mL, respectively. After clinical study, Ag NPs containing Citrus sinensis leaf aqueous extract may be used to formulate a new chemotherapeutic drug or supplement to treat the several types of human lung adenocarcinoma.     

Isolation,Characterization, Complete Structural Assignment,and Anticancer Activities of the Methoxylated Flavonoids from Rhamnus disperma Roots

Different chromatographic methods including reversed-phase HPLC led to the isolation and purification of three O-methylated flavonoids; 5,4’-dihydroxy-3,6,7-tri-O-methyl flavone (penduletin) (1), 5,3’-dihydroxy-3,6,7,4’,5’-penta-O-methyl flavone (2), and 5-hydroxy-3,6,7,3’,4’,5’-hexa-O-methyl flavone (3) from Rhamnus disperma roots. Additionlly, four flavonoid glycosides; kampferol 7-O-α-L-rhamnopyranoside (4), isorhamnetin-3-O-β-D-glucopyranoside (5), quercetin 7-O-α-L-rhamnopyranoside (6), and kampferol 3, 7-di-O-α-L-rhamnopyranoside (7) along with benzyl-O-β-D-glucopyranoside (8) were successfully isolated. Complete structure characterization of these compounds was assigned based on NMR spectroscopic data, MS analyses, and comparison with the literature. The O-methyl protons and carbons of the three O-methylated flavonoids (1–3) were unambiguously assigned based on 2D NMR data. The occurrence of compounds 1, 4, 5, and 8 in Rhamnus disperma is was reported here for the first time. Compound 3 was acetylated at 5-OH position to give 5-O-acetyl-3,6,7,3’,4’,5’-hexa-O-methyl flavone (9). Compound 1 exhibited the highest cytotoxic activity against MCF 7, A2780, and HT29 cancer cell lines with IC₅₀ values at 2.17 µM, 0.53 µM, and 2.16 µM, respectively, and was 2–9 folds more selective against tested cancer cell lines compared to the normal human fetal lung fibroblasts (MRC5). It also doubled MCF 7 apoptotic populations and caused G₁ cell cycle arrest. The acetylated compound 9 exhibited cytotoxic activity against MCF 7 and HT29 cancer cell lines with IC₅₀ values at 2.19 µM and 3.18 µM, respectively, and was 6–8 folds more cytotoxic to tested cancer cell lines compared to the MRC5 cells.     

Phytochemical profiles,antioxidant and anti-acetylcholinesterasic activities of the leaf extracts of Rhamnus lycioides subsp. oleoides (L.) Jahand. & Maire in different solvents

In this work, the extracts obtained with different solvents from the leaves of Rhamnus lycioides subsp. oleoides (L.) Jahand. & Maire were studied for their phytochemical profile and then for their antioxidant and acetylcholinesterase inhibitory activities. The phytochemical profiles of the extracts in n-hexane, dichloromethane, ethyl acetate, methanol, anthraquinone rich and water, showed the presence of different compounds belonging to several classes of natural products such as flavonoids, anthraquinones, saccharides and fatty acids. For what concerns the biological tests, the ethyl acetate, methanol and anthraquinone rich extracts showed the highest activities in both assays due to the high amount of compounds possessing those properties such as flavonoids and anthraquinones. By consequence, these specific extracts of the species may be considered to be potential sources of natural antioxidant and anti-acetylcholinesterasic compounds.     

Durian waste mediated green synthesis of zinc oxide nanoparticles and evaluation of their antibacterial,antioxidant, cytotoxicity and photocatalytic activity

ABSTRACT

The synthesized ZnO NPs using durian rind in solution has shown maximum absorption at 355.5?nm with the bandgap of 3.33?eV, spectrophotometrically. SEM and TEM studies revealed that the shape of the synthesized ZnO NPs was spherical with an average size of 280 and 283?nm, respectively. However, DLS analysis of ZnO NPs revealed the average particle size of 456?d.nm. The presence of [100], [002], [101], [102], [110], [103], [200], [112] and [201] planes in XRD corroborate the formation of pure wurtzite structure of ZnO NPs. Synthesized ZnO NPs showed remarkable photocatalytic activity on degradation of methylene blue and sulfanilamide, antioxidant activity, considerable antimicrobial activity against Escherichia coli and Staphylococcus aureus, and considerable cytotoxic activity against brine shrimp. The sulfanilamide degradation was found to be 96.70%, under natural sunlight and in the presence of 0.1% ZnO NPs at pH 10 with a time of 3?h. The dye degradation was found to be 84% under sunlight in the presence of 0.01% ZnO NPs at pH 10 with a time of 40?min. The synthesized ZnO NPs may be explored furthermore in the fields of wastewater treatment, biomedicine, biosensor, and nanotechnology.     

Phytogenic fabrication of iron oxide nanoparticles and evaluation of their in vitro antibacterial and cytotoxic activity

Several metal-based nanoparticles (NPs) have been found to be toxic and are known to exert adverse health outcomes with irreversible side effects. This highlights the need to discover effective, stable, and biocompatible therapeutic components using natural sources. Here, a hexane extract of Nigella sativa seeds was used to synthesize iron oxide NPs (NS-IONPs) embedded with N. sativa phytoconstituents. The extract acted as a reducing agent that restricted the size of the NS-IONPs to 5–6 nm, signifying the potential to be cleared through the renal system. The fabricated NS-IONPs had a prominent effect on pathogenic gram-negative bacteria, E. coli (19.3 mm) and Salmonella typhi (14.2 mm) and lung cancer cells (lowest IC₅₀ of 18.75 µg/mL) mainly by binding to the phospholipid components of the cell membrane. This resulted in cell shrinkage and further inhibited cell growth. Transmission electron microscopy analyses revealed that the mechanisms of cellular NP uptake varied depending on the cell type. Accumulation of NS-IONPs inside the cell increased BAX expression and arrested the cells at the G0/G1 phase, thereby conspicuously extending the G0 phase to initiate necrosis. Thus, these finding suggest that the synthesized NS-IONPs exhibited high antibacterial activity and effective cytotoxicity against cancer cell lines A549 and HCT116 compared to IONPs. The innovation of the current study is that the biogenic fabrication of IONPs is simple and cost effective results in stable nanomaterial, NS-IONPs with potential antibacterial and anticancer activity, which can be explored furthermore for various biomedical applications.     

Analysis and evaluation of the antimicrobial and anticancer activities of the essential oil isolated from Foeniculum vulgare from Hamedan,Iran

In this study, biological properties of the essential oil isolated from seeds of Foeniculum vulgare (F. vulgare) were evaluated. GC-MS analysis revealed Trans-Anethole (80.63%), L-Fenchone (11.57%), Estragole (3.67%) and Limonene (2.68%) were the major compounds of the essential oil. Antibacterial activity of the essential oil against nine Gram-positive and Gram-negative strains was studied using disc diffusion and micro-well dilution assays. Essential oil exhibited the antibacterial activity against three Gram-negative strains of Pseudomonas aeruginosa, Escherichia coli, and Shigella dysenteriae. The preliminary study on toxicity of seed oil was performed using Brine Shrimp lethality test (BSLT). Results indicated the high toxicity effect of essential oil (LC50 = 10 μg/mL). In vitro anticancer activity of seed oil was investigated against human breast cancer (MDA-Mb) and cervical epithelioid carcinoma (Hela) cell lines by MTT assay. Results showed the seed oil behave as a very potent anticancer agent with IC50 of lower than 10 μg/mL in both cases.     

Antibacterial and antioxidant properties of phyto-synthesized silver nanoparticles using Lavandula stoechas extract

Due to environmentally friendly and cost- effective issues, biological methods for silver nanoparticles (AgNPs) synthesis are advantageous over chemical and physical ones. In this study, AgNPs synthesized using Lavandula stoechas extract as a reductant and its antioxidant capacity, antibacterial property and cytotoxicity effect were investigated. The phyto-synthesized AgNPs were characterized using various analyses such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD) as well as Fourier transform infrared (FT-IR). The prepared nanoparticles were spherical on shape with the size about 20–50 nm. Antibacterial studies through agar disk diffusion method confirmed the antibacterial potential of phyto-synthesized AgNPs toward two clinical Staphylococus aureus and Pseudomonas aeruginosa bacteria, although MTT assay demonstrated that S. aureus (MIC = 125 μg/ml) was more susceptible to AgNPs than P. aeruginosa (MIC = 250 μg/ml). Moreover, the cytotoxicity assay of phyto-synthezied AgNPs showed a low cytotoxic effect on RAW264 cell line at 62.5 μg/ml as an effective concentration. Also the considerable antioxidant capacity of the AgNPs confirmed through DPPH assay. Great antibacterial and antioxidant properties along with biocompatibility make the suggested phyto-synthesized AgNPs a great candidate for different biomedical applications including wound healing.     

New metal complexes of sulfonamide: Synthesis,characterization, in‐vitro anticancer,anticholinesterase, antioxidant,and antibacterial studies

In this research work a sulfonamide from tranexamic acid has been synthesized followed by its metal complexation. p‐Bromo benzene sulfonyl chloride was used to synthesize sulfonamide using eco‐friendly atmosphere. The sulfonamide prepared from tranexamic acid has been utilized for the preparation of metal complexes with various metals like Ni, Cu, Co, Mn, Pb, Cd, Cr, Fe, Sn, and Sr. All synthesized compounds were characterized by applying different spectral techniques such as Fourier‐transform infrared (FTIR), mass spectrometry, and X‐ray diffraction (XRD) analysis. The biological activities such as radical scavenging activity, enzyme inhibition, antifungal, antibacterial, and anticancer were performed. It was concluded from the results that compounds showed moderate to good activity. Cu complex of sulfonamide showed the highest antioxidant potential (87.69 ± 1.8% with IC₅₀ 137 ± 1.0 μg) while Cr complex depicted the highest activity against both enzymes; AChE (73.51 ± 1.7% with IC₅₀ 165 ± 1.1 μg) and BChE (70.05 ± 1.3% with IC₅₀ 152 ± 1.8 μg). Mn complex showed good results against six bacterial strains comparable with standard drug. Cr complex depicted highest anticancer activity against MCF7 and human corneal epithelial cell (HCEC) cell lines 45.73% and 25.40%, respectively. These results concluded that metal complexes of sulfonamide may be good induction in the future for medical purposes.     

Optimization and ecofriendly synthesis of iron oxide nanoparticles as potential antioxidant

The present study involves the use of Box-Behnken design for optimization of the energy-efficient process variables, eco-friendly synthesis of nanoparticles of iron oxide using Coriandrum sativum L. (cilantro) leaf extract. The factors, which significantly influenced mean nanoparticle size, surface charge, and size distribution, were the volume of leaf extract, agitation speed, and temperature. The developed model using Box-Behnken design was validated by synthesizing the iron nanoparticles using optimized operational conditions i.e. 10 ml volume of leaf extract, 1500 rpm agitation speed and 30 °C temperature. This resulted in the formation of highly stable iron oxide nanoparticles with mean particle size 161.5 nm and polydispersity index 0.132 with a zeta potential of −19.5 mV. The free radical inhibitory activity of prepared iron oxide nanoparticles was found comparable to ascorbic acid. These results reveal that iron nanoparticles for a biomedical application can be prepared at ambient temperature in an eco-friendly manner.     

Chemical composition and in vitro anticancer,antimicrobial and antioxidant activities of essential oil and methanol extract from Rumex nervosus

Chemical composition, antioxidant, anticancer, and antimacrobial activities of essential oil obtained from leaves of Rumex nervosus has been evaluated here for the first time. GC/MS analysis reveals the presence of Palmitoleic Acid (28.35%) and Palmitic acid, (25. 37%) as their methyl ester as major components. The essential oil showed significant DPPH radical scavenging activity (94.907 ± 0.1089% and 94.003 ± 0.0749%) at concentration (100 and 80) μg/mL respectively. The oil showed promising activity against staph aureus, while showed weak activity against (Hela and 3T3) cell lines. The crude extract / fractions of R. nervosus (leaves) showed significant antioxidant activity at dose (100 and 80) μg/mL. Futhermore the crude showed significant activity against (MCF-7 and MDA-MB-231) cell lines with IC₅₀ (20.5138 ± 0.933 and 25.1728 ± 0.9176) μg/mL respectively, and chloroform fraction showed good activity against (MCF-7 and MDA-MB-231) cell lines with IC₅₀ (31.154 ± 0.965 and 42.269 ± 2.1045) μg/mL.     

Falcaria vulgaris leaf aqueous extract mediated synthesis of iron nanoparticles and their therapeutic potentials under in vitro and in vivo condition

In recent years, researchers have used bionanotechnology techniques as cost‐effective and eco‐friendly routes to fabricate nanoparticles. The present study confirms the ability of aqueous extract of Falcaria vulgaris for the biosynthesis of iron nanoparticles (FeNPs@F. vulgaris). Also, in this study, we showed the antioxidant, cytotoxicity, cutaneous wound healing, antibacterial, and antifungal activities of these nanoparticles. FeNPs@F. vulgaris were characterized by UV, FT‐IR, XRD, FE‐SEM, and TEM analysis. According to the XRD analysis, 25.3 nm was measured for the crystal size of nanoparticles. FE‐SEM and TEM images exhibited a uniform spherical morphology and average diameters of 25 nm for the biosynthesized nanoparticles. FTIR results offered protein and polysaccharides in F. vulgaris were the sources of reducing power, reducing iron ions to FeNPs@F. vulgaris. In vivo design, FeNPs@F. vulgaris ointment remarkably reduced (p ≤ 0.01) the wound area, total cells, neutrophil, and lymphocyte and substantially increased (p ≤ 0.01) the wound contracture, vessel, hydroxyl proline, hexosamine, hexuronic acid, fibrocyte, and fibrocytes/fibroblast rate compared to other groups in rats. Also, FeNPs@F. vulgaris indicated potential antioxidant activity against DPPH, antifungal potentials against Candida glabrata, Candida albicans, Candida krusei, and Candida guilliermondii, antibacterial properties against Gram‐positive bacteria (Streptococcus pneumonia, Staphylococcus aureus, and Bacillus subtilis) and Gram‐negative bacteria (Salmonella typhimurium, Pseudomonas aeruginosa, and Escherichia coli O157:H7) without any cytotoxicity effect against human umbilical vein endothelial cells. Finally, the results showed the useful antioxidant, non‐cytotoxic, cutaneous wound healing, antifungal, and antibacterial effects of FeNPs@F. vulgaris.     

Aerva lanata flower extract mediated green synthesis of silver nanoparticles: Their characterization,in vitro antioxidants and antimicrobial investigations

The production of nanoparticles (NPs) using biological methods may lead to the enhancement of clean, non-hazardous, and environmentally acceptable procedures. With this context, in the present study silver nanoparticles (AgNPs) were synthesized using the flower extract of Aerva lanata (A. lanata). The following techniques, including UV–visible spectroscopy, XRD, Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR), are used to study the crystalline nature, size, shape, and elemental composition of the biosynthesized AgNPs, and antimicrobial applications of the NPs also studied. In UV–visible spectroscopy results a strong absorbance peak at 425 nm confirmed the AgNPs. The SEM results confirmed the spherical shape of the NPs and their average size of 45.05 nm. X-ray diffractometry XRD spectra confirmed the crystalline nature of the AgNPs. Against the DPPH (2,2-diphenyl-1-picrylhydrazyl), nitric oxide and superoxide radicals, Alf-AgNPs and ascorbic acid had significant scavenging effects at higher concentration of 250 μg/mL, exhibited 65.76 ± 0.41% and 86.42 ± 0.69%, 78.39 ± 0.49% and 72.72 ± 0.14% and 70.79 ± 0.87% and 72.79 ± 0.33% inhibition, respectively. As produced AgNPs had strong antibacterial and moderate antifungal activities against pathogenic test bacterial strains viz. Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), Escherichia coli (E. coli), and Klebsiella pneumonia (K. pneumonia) with the maximum zone of inhibition 15 ± 1.07 mm, 12 ± 0.96 mm, 14 ± 1.05 mm, and 15 ± 2.54 mm, respectively at maximum (75 μg/mL) concentration of AgNPs, and the zone of inhibition of fungal strains Aspergillus fumigatus (A. fumigatus) (9 ± 0.67 mm) and Candida albicans (C. albicans) (7 ± 0.75 mm) at 75 μg/mL. It was eventually concluded that the biosynthesized Alf-AgNPs showed promising antioxidant and antimicrobial agents with very low concentrations.     

Magnetic iron oxide nanoparticles for biorecognition: evaluation of surface coverage and activity

Modifying the surfaces of magnetic nanoparticles (MNPs) by the covalent attachment of biomolecules will enable their implementation as contrast agents for magnetic resonance imaging or as media for magnetically assisted bioseparations. In this paper we report both the surface coverage and the activity of IgG antibodies on MNPs. The antibodies were immobilized on gamma-Fe2O3 nanoparticles by conventional methods using aminopropyltriethoxy silane and subsequent activation by glutaraldehyde. Novel fluorescence methods were used to provide a quantitative evaluation of this well-known approach. Our results show that surface coverage can be stoichiometrically adjusted with saturated surface coverage occurring at approximately 36% of the theoretical limit. The saturated surface coverage corresponds to 34 antibody molecules bound to an average-sized MNP (32 nm diameter). We also show that the immobilized antibodies retain approximately 50% of their binding capacity at surface-saturated levels.