Dynamic Light Scattering Spectroscopy Research Articles

Evaluation of Cr(VI) Removal from Tanning Effluents Using Magnetic Nanoparticles of Fe3O4 Synthesized with Olea europaea Bone Extract.

The tanning industry generates effluents with high chromium content, which require treatment prior to discharge into the sewage system. This article explores the use of magnetic magnetite nanoparticles (MNPs) to remove Cr(VI) from aqueous solutions, such as tanning effluents. The MNPs were synthesized by coprecipitation reaction using the Olea europaea extract as a reducing agent. Subsequently, they were characterized by dynamic light scattering spectroscopy (DLS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). MNPs with irregular morphology and diameters ranging from 73.28 to 162.90 nm were obtained. Cr(VI) removal was performed using jar test methodology, and its efficiency was evaluated in the laboratory for different initial Cr(VI) (mg/L) concentration and nanoparticle (g/L) concentration. A kinetic study was developed and indicated that the equilibrium adsorption mechanism corresponds to a pseudo-second-order model. Furthermore, the isotherm analysis revealed that chromium adsorption best fits the Langmuir isotherm. Finally, Cr(VI) removal rates from 85% to 100% were achieved in tanning and retanning effluents.

Green Synthesis of CuO Nanoparticles Using Agaricus bisporus Extract as a Highly Efficient Catalyst for the Suzuki Cross-Coupling Reaction.

Copper oxide nanoparticles (CuONPs) were synthesized using a rapid, eco-friendly, cost-effective, efficient, and biological method employing aqueous Agaricus bisporus extract as a capping and reducing agent. The formation of CuONPs was checked by UV-vis spectroscopy and was characterized by X-ray diffraction analysis (XRD), dynamic light scattering spectroscopy (DLS), transmission electron microscopy (TEM), and surface area and porosimetry analyzer. The characterization results showed that the synthesized nanoparticles had a spherical-like appearance and a crystal structure with 40-100 nm particle size. The green synthesized CuONPs were found to be an excellent and sustainable heterogeneous catalyst (TOF up to 29700 h-1 ) for the Suzuki C-C coupling of aryl halides with phenylboronic acid in a very short reaction time (10 minutes). Moreover, the easily recovered catalyst can be reused five times with just a negligible reduction in catalytic behavior.

Decentralized core-shell Au/Ag bimetallic nanostructures prepared via green approach for catalytic and antimicrobial applications

Synthesis of noble metallic nanomaterials via green routes using various plant extracts has witnessed a remarkable rise in applications and research interest over the past decade. These biogenic routes are devoid of toxic chemicals, harsh preparation environments, and external capping agents, coupled with their cost-effectiveness, have attracted researchers to adopt green chemistry in nanotechnology. In this study, we synthesized Au, Ag, and Au/Ag nanoparticles (NPs) using a facile method employing an extract derived from a mixture of spices. Optical, morphological, and structural analysis is carried out using UV-visible spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDAX), Fourier- transform infrared spectroscopy (FTIR), and X-ray diffraction studies (XRD), respectively. The Zeta potential of the prepared NPs was determined using dynamic light scattering spectroscopy (DLS). Optimization of pH to 10 and 8 was performed for the synthesis of Ag and Au NPs, respectively, crucial for precise tuning of their optical absorption spectra. Finite difference time domain (FDTD) simulations validate the experimental findings. The Ag NPs exhibit primarily uniform and spherical size and shape, whereas the Au NPs display a variety of shapes including spheres, rods, and triangular plates. This variation is attributed to the influence of pH and concentration of precursors. TEM analysis confirmed the formation of Au/Ag bimetallic core-shell nanostructures (NSs), characterized by a decentralized gold core. XRD confirmed the formation of FCC crystallites. FTIR spectra identified the possible biological functional groups responsible for reduction and capping. Furthermore, a negative zeta potential exceeding 20 mV confirmed the stable formation of NPs. These NPs were capped by negatively charged functional groups, thereby avoiding agglomeration. Both mono and bimetallic NSs exhibited enhanced catalytic activity for reducing 4-nitrophenol in the presence of sodium borohydride (NaBH4). Furthermore, Ag and Au/Ag NPs have exhibited antibacterial properties against specific bacteria, which are discussed in detail.

Green synthesized copper assisted iron oxide nanozyme for the efficient elimination of industrial pollutant via peroxodisulfate activation

Herein, a series of nanocomposites, CuxFe1-xO (where, x = 0.05, 0.10, 0.15 termed as CuI 1, CuI 2 and CuI 3 respectively) had been synthesized by Punica Granatum peel (PGP) extract. These composites were characterized by different techniques. Formation of the nanocomposites was confirmed by Ultraviolet-visible spectroscopy (Uv-vis), Energy dispersive X-ray (EDX) and Fourier-transformed infrared spectroscopy (FTIR). The shape and average sizes of the particles were analyzed by the X-ray diffraction (XRD) technique, scanning electron microscope (SEM) and dynamic light scattering spectroscopy (DLS). The removal of organic pollutant, methylene blue dye (MB) through sodium peroxodisulfate (PDS) activation and enzyme mimicking activities were performed by the nanocomposites. As CuI 1 performed best, different controlling parameters and kinetics of the reactions were studied for CuI 1 catalyst cum nanozyme. The calculated rate constant for dye degradation by CuI 1 was found to be 0.01868 min−1 and the kinetic parameters’ value for the enzyme mimicking activities was Km = 0.04878072 mM and Vmax = 2.221877 M min−1. From the thermodynamic study of the degradation process, the obtained activation energy, Ea = 30.93 kJ/mol suggested the dependency of reaction rate on temperature significantly.

Diospyros malabarica Fruit Extract Derived Silver Nanoparticles: A Biocompatible Antibacterial Agent

Biogenic silver nanoparticles demonstrate excellent antibacterial activity against a broad range of bacteria. Herein, aqueous biogenic silver nanoparticles (Aq@bAgNPs) and ethanolic biogenic silver nanoparticles (Et@bAgNPs) were synthesized using aqueous as well as ethanolic extracts of Diospyros malabarica fruit, respectively. The as-prepared biogenic silver nanoparticles (bAgNPs) were characterized using UV-Vis, FTIR as well as energy dispersive X-ray (EDS) spectroscopy, electron microscopy, dynamic light scattering spectroscopy (DLS), and zetasizer. The zeta potentials of Aq@bAgNPs and Et@bAgNPs were −9.8 ± 2.6, and −12.2 ± 1.9 mV, respectively. The antibacterial activity of bAgNPs was investigated against seven bacterial strains (i.e., pathogenic and nonpathogenic) and Et@bAgNPs exhibited the highest antibacterial propensity (i.e., 20 nm in diameter) against Bacillus subtillis through disk diffusion assay. The trypan blue dye exclusion assay also confirmed the antibacterial propensity of as-prepared bAgNPs. Furthermore, both Aq@bAgNPs and Et@bAgNPs oxidize bacterial membrane fatty acids and generate lipid peroxides which eventually form complexes with thiobarbituric acid (i.e., malondialdehyde-thiobarbituric acid adduct) to bring about bacterial death. Both the nanoparticles demonstrated good hemocompatibility against human as well as rat red blood cells (RBCs). In addition, they exhibited excellent biocompatibility in vivo in terms of rat liver (i.e., serum ALT, AST, and γ-GT) and kidneys (i.e., serum creatinine) function biomarkers.

Usnic acid induced changes in biomolecules and their association with apoptosis in squamous carcinoma (A-431) cells: A flow cytometry, FTIR and DLS spectroscopic study

Many natural products induce apoptotic cell death in cancer cells, though studies on their interactions with macromolecules are limited. For the first time, this study demonstrated the cytotoxic potential of usnic acid (UA) against squamous carcinoma (A-431) cells and the associated changes in cell surface proteins, lipids and DNA by attenuated total reflection- fourier transform infrared spectroscopy (ATR-FTIR) and dynamic light scattering (DLS) spectroscopic studies. The IC50 for UA was 98.9 µM after treatment of A-431 cells for 48 h, while the IC50 reduced to 39.2 µM after 72 h of incubation time. UA induced oxidative stress in treated cells as confirmed by DCFHDA flow cytometry assay, depletion in reduced glutathione and increase in lipid peroxidation. The oxidative stress resulted in conformation change in amide I, amide II protein bands and DNA as observed by ATR-FTIR in UA treated A-431 cells. Shift in secondary structures of proteins from α helix to β sheets and structural changes in DNA was observed in UA treated A-431 cells. An increase in the band intensity of phospholipids, increased distribution of lipid and change in membrane potential was noted in UA treated cells, which was confirmed by externalization of phosphatidylserine to the outer membrane by annexin V-FITC/PI assay. Increase in mitochondrial membrane potential, cell cycle arrest at G0/G1 phase by flow cytometry and activation of caspase-3/7 dependent proteins confirmed the UA induced apoptosis in treated A-431 cells. FTIR and DLS spectroscopy confirmed the changes in biomolecules after UA treatment, which were associated with apoptosis, as observed by flow cytometry.

Biosynthesis of Silver Nanoparticles by Marine Actinobacterium Nocardiopsis dassonvillei and Exploring Their Therapeutic Potentials.

Nanoparticles have recently emerged as a popular research topic. Because of their potential applications in therapeutic applications, biosynthesized silver nanoparticles (Bio-AgNPs) have gained much attention in recent years. Cell-free extracts (CFE) from a marine culture of actinobacteria and silver nitrate were used to reduce Ag+ ions and create Bio-AgNPs. Nocardiopsis dasonvillei KY772427, a new silver-tolerant actinomycete strain, was isolated from marine water and used to synthesize AgNPs. In order to characterize Bio-AgNPs, UV-Vis spectral analysis, Fourier transform infrared (FTIR), transmission electron microscopy (TEM), and dynamic light scattering spectroscopy (DLS) were all utilized. Using UV–Vis spectroscopy, a peak in the surface plasmon resonance (SPR) spectrum at 430 nm revealed the presence of Bio-AgNPs. The TEM revealed spherical AgNPs with a diameter of 29.28 nm. DLS determined that Bio-AgNPs have a diameter of 56.1 nm and a negative surface charge (−1.46 mV). The minimum inhibitory concentration (MIC) of Bio-AgNPs was determined against microbial strains. Using resazurin-based microtiter dilution, the synergistic effect of Bio-AgNPs with antimicrobials was investigated. Pseudomonas aeruginosa had the lowest MIC of Bio-AgNPs (4 μg/ml). Surprisingly, the combination of antimicrobials and Bio-AgNPs had a significant synergistic effect on the tested strains. The insecticidal activity of Bio-AgNPs (200 μg/ml) against Macrosiphum rosae was found to be maximal after 36 h. Additionally, Bio-AgNPs demonstrated significant scavenging activity against 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl (OH–) radicals, with IC50 values of 4.08 and 8.9 g/ml, respectively. In vitro studies using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay revealed a concentration-dependent decrease in cell viability when CaCo2 cells were exposed to Bio-AgNPs. With the decrease in cell viability, lactate dehydrogenase leakage (LDH) increased. The findings of this study open up a new avenue for the use of marine Nocardiopsis dasonvillei to produce Bio-AgNPs, which have significant antimicrobial, antioxidant, insecticidal, and anticancer potential.

Effect of the green synthesis of CuO plate-like nanoparticles on their photodegradation and antibacterial activities.

Green synthesis of copper oxide nanoparticles and its effects on photocatalytic dye degradation and antibacterial activities are reported. The synthesis of nanoparticles by green routes provides many advantages over chemical routes, including simplicity, cost-effectiveness, and fast processing route without using any costly or harmful chemicals. Tridax procumbense (coat buttons) plant root extract was used to synthesize copper oxide nanoparticles. The synthesized Tridax procumbense-copper oxide nanoparticles (TP-CuO NPs) were characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering spectroscopy (DLS), and X-ray diffraction (XRD) techniques. The synthesized TP-CuO NPs were applied for photocatalytic dye degradation and antibacterial activity studies. The TP-CuO NPs exhibited a maximum antibacterial activity at 500 μg mL-1 concentration against Staphylococcus aureus and E. coli showing inhibition zones of 7.5 mm and 7.2 mm, respectively. The photocatalytic ability of the TP-CuO was also tested against the textile dye Trypan blue (TB), and showed about 55% degradation after 48 h for 500 μg mL-1 CuO NP concentration, showing a concentration-dependent degradation efficiency. This is the first work on TP-derived CuO nanoparticles and their photocatalytic and antimicrobial applications. Overall, this study supports the superiority of green-synthesized TP-CuO NPs as photocatalytic and antimicrobial agents.

Biogenic Synthesis of Silver Nanoparticles using Azadirachta indica (Neem) Leaf Extract To Achieve Inhibitory Action Against Antibiotic-Resistant Bacteria

Background: Nanotechnology is an emerging research field on nanoparticles. Nanoparticles are 1-100 nm in one dimension and are important in biomedical science, medical chemistry, atomic physics, and most other known fields. They are used because of their small size, orientation, and physical properties. Objectives: This study was designed to synthesize silver nanoparticles (AgNPs) using Azadirachta indica (Neem) leaf extract and evaluate their biomedical application. Methods: An aqueous extract of Azadirachta indica was used to synthesize AgNPs. 1 ml of the extract was added drop by drop to 30-60 ml of a 1mM solution of silver nitrate. The AgNPs were characterized by UV-Visible Spectroscopy, Fourier Transform Infrared Spectroscopy, Dynamic Light Scattering Spectroscopy, X-ray Diffraction, Transmission Electron Microscopy, and antibacterial activity studies. The biological synthesis of AgNPs was performed using the aqueous solution of Azadirachta indica leaf extract and AgNO3. A fixed ratio of plant extract to metal ion was used to prepare AgNPs and the formation of the nanoparticles was confirmed through the color change. The nanoparticles were characterized by UV-vis spectrophotometer, FTIR, DLS, XRD and TEM, and were found to range in size from 30-60 nm. Results: The biosynthesized AgNPs had a bactericidal effect against the antibiotic resistant pathogenic microorganisms Bacillus subtilis, Pseudomonas aeruginosa, and Bacillus cereus. Conclusion: Silver nanoparticles were synthesized from Azadirachta indica leaf extract and can be used as a therapeutic candidate for biomedical applications.

In Vitro Antioxidant, Antitumor and Photocatalytic Activities of Silver Nanoparticles Synthesized Using Equisetum Species: A Green Approach.

The ethanolic extracts of three Equisetum species (E. pratense Ehrh., E. sylvaticum L. and E. telmateia Ehrh.) were used to reduce silver ions to silver nanoparticles (AgNPs). The synthesized AgNPs were characterized using UV-Vis spectrophotometry, Fourier Transform Infrared Spectroscopy (FTIR), Energy Dispersive X-ray (EDX), Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS) measurements. FTIR data revealed the functional groups of biomolecules involved in AgNPs synthesis, such as O-H, C-H, C=O, C-O, and C-C. EDX spectroscopy was used to highlight the presence of silver, while DLS spectroscopy provided information on the mean diameter of AgNPs, that ranged from 74.4 to 314 nm. The negative Zeta potential values (−23.76 for Ep–AgNPs, −29.54 for Es–AgNPs and −20.72 for Et–AgNPs) indicate the stability of the obtained colloidal solution. The study also focused on establishing the photocatalytic activity of AgNPs, which is an important aspect in terms of removing organic dyes from the environment. The best photocatalytic activity was observed for AgNPs obtained from E. telmateia, which degraded malachite green in a proportion of 97.9%. The antioxidant action of the three AgNPs samples was highlighted comparatively through four tests, with the best overall antioxidant capacity being observed for AgNPs obtained using E. sylvaticum. Moreover, the biosynthesized AgNPs showed promising cytotoxic efficacy against cancerous cell line MG63, the AgNPs obtained from E. sylvaticum L. providing the best result, with a LD50 value around 1.5 mg/mL.

Silver Nanoparticles for a Colorimetric Determination of Putrescine and Cadaverine in Biological Samples.

A convenient and uncomplicated scheme has been projected for the quantitative determination of essential diamines putrescine (PUT) and cadaverine (CAD) via sodium dodecyl sulfate protected silver nanoparticles (SDS-AgNPs). This scheme is based on the chemical interaction of a SDS-AgNPs probe with PUT and CAD, leading to a color change from yellow to red or reddish brown. The interaction was investigated through different techniques such as using a UV-visible spectrophotometer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), dynamic light scattering spectroscopy (DLS) and the zeta potential. Both amines possess a close resemblance in structure (except for the addition of one more methylene group in CAD), and no any distinguishable color change was noted. However, the maximum absorption band at 580 and 600 nm was demonstrated for PUT and CAD correspondingly. The methodical response was observed at absorption ratios of 580/410 and 600/410 nm, with the linear regression within 4 - 12 and 6 - 14 μg/mL for PUT and CAD. The detection limits calculated for both the diamines PUT and CAD were 0.333 and 1.638 μg/mL. The scheme was successfully applied for determinations in biological samples, including spiked blood plasma and urine. Putrescine exhibited % recovery within 95.717 - 105.200%, while cadaverine was within 95.940 - 105.109%, respectively. The scheme was reproducible and precise with inter-day RSD (n = 5) within 1.126, 0.018% and the intraday RSD (n = 5) was within 0.005, 0.002% for PUT and CAD, respectively.

Synthesis and Stabilization of Support-Free Mesoporous Gold Nanoparticles.

Porous gold nanoparticles (PGNs) are usually prepared in an immobilized form on a solid substrate, which is not practical in many applications. In this work, a simple method is reported for the preparation and stabilization of mesoporous gold particles of a few hundred nanometers in size in aqueous suspension. Nanoparticles of Ag-Au alloy were fabricated on CaF and Si/SiO substrates by the solid-state dewetting method. Silver was selectively dissolved (dealloyed), and the resulting porous gold nanoparticles were chemically removed from the substrate either in a concerted step with dealloying, or in a subsequent step. Nitric acid was used for the one-step dealloying and detachment of the particles from CaF substrate. The consecutive use of HNO and HF resulted in the dealloying and the subsequent detachment of the particles from Si/SiO substrate. The PGNs were recovered from the aqueous suspensions by centrifugation. The Au content of the suspensions was monitored by using elemental analysis (ICP-OES), and recovery was optimized. The morphology and the optical characteristics of the support-free PGNs were analyzed by scanning electron microscopy (SEM), dynamic light scattering spectroscopy (DLS), and near-infrared spectrophotometry (NIR). The obtained PGNs are spherical disk-shaped with a mean particle size of 765 ± 149 nm. The suspended, support-free PGNs display an ideally narrow dipole plasmon peak at around 1450 nm in the NIR spectral region. Thus, the new colloidal PGNs are ideal candidates for biomedical applications, for instance photothermal therapy.

Preparation of DABCO‐Based Acidic‐Ionic‐Liquid‐Supported ZnO Nanoparticles and Their Application for Ecofriendly Synthesis of N‐Aryl Polyhydroquinoline Derivatives

AbstractHere we have reported a new significant DABCO based acidic ionic liquid ([DABCO(C2COOH)2]2+[Br−]2). With the assistance of this IL, ZnO nanoparticle (NP) supported [DABCO (C2COOH)2]2+[Br−]2 immobilised ZnO‐[DABCO(C2COOH)2]2+[Br−]2 was established, a new supported Catalyst with an ionic liquid layer (SCILL,). Since ZnO nanoparticles are amphoteric in nature and DABCO based ionic liquid is acidic in nature, it posses both acidic and basic catalytic site in a single moiety. With the assistance of this quasi heterogeneous, efficient, recyclable catalyst we were able to produce series of N‐aryl hexahydroquinolines in aqueous medium with good to excellent yield within shorter reaction time. This catalyst was characterised by Scanning Electron Microscope (SEM), High Resolution Transmission Electron Microscope (HRTEM), Energy Dispersive Analysis X‐ray (EDAX), Dynamic Light Scattering Spectroscopy (DLS), Powder X‐Ray Diffraction (PXRD), Thermo Gravimetric Analysis (TGA) and Fourier Transform Infrared spectroscopy (FT‐IR). Here, synergetic catalytic effect of amphoteric heterogeneous zinc oxide nanoparticles and acidic homogeneous DABCO based ionic liquid were commendably compiled.

Molecular Aggregation of Marketed Recombinant FVIII Products: Biochemical Evidence and Functional Effects.

Background Recombinant (rec-) coagulation factor VIII concentrates available for hemophilia A (HA) treatment differ in cell line production and structure, which could affect their pharmacodynamics and immunogenicity. Clinical trials showed that previously untreated patients with severe HA present higher rates of inhibitor development if treated with rec-FVIII products and that differences do exist as to inhibitor's formation among different rec-FVIII products. This finding could arise from several causes, such as absence of von Willebrand factor, different glycosylation profiles, or processes of molecular aggregation of the recombinant FVIII molecules. Objectives/Methods In this study, using size exclusion high-performance liquid chromatography (SE-HPLC), dynamic light scattering (DLS) spectroscopy, and functional biochemical assays, we investigated the purity grade, FX activating ability, and aggregation status of three recombinant marketed products (Advate [Baxalta], Refacto AF [Pfizer], and Kogenate [Bayer]). Results The overall analysis of the results obtained with SE-HPLC and DLS spectroscopy showed that the three recombinant FVIII concentrates contain low but significant amounts of molecular aggregates. This phenomenon was less evident for the Advate product. Molecular aggregation negatively affects the in vitro pharmacodynamics of the concentrates with higher aggregates' content. Conclusions This study shows that the three pharmaceutical formulations of recombinant FVIII contain variable amounts of molecular aggregates after their reconstitution at therapeutic concentrations. This phenomenon negatively affects the in vitro potency of the products with higher aggregates' content and might be invoked as a contributing cause of their increased risk to induce the formation of FVIII inhibitors.

Nanostructured Materials for Food Applications: Spectroscopy, Microscopy and Physical Properties.

Nanotechnology deals with matter of atomic or molecular scale. Other factors that define the character of a nanoparticle are its physical and chemical properties, such as surface area, surface charge, hydrophobicity of the surface, thermal stability of the nanoparticle and its antimicrobial activity. A nanoparticle is usually characterized by using microscopic and spectroscopic techniques. Microscopic techniques are used to characterise the size, shape and location of the nanoparticle by producing an image of the individual nanoparticle. Several techniques, such as scanning electron microscopy (SEM), transmission electron microscopy/high resolution transmission electron microscopy (TEM/HRTEM), atomic force microscopy (AFM) and scanning tunnelling microscopy (STM) have been developed to observe and characterise the surface and structural properties of nanostructured material. Spectroscopic techniques are used to study the interaction of a nanoparticle with electromagnetic radiations as the function of wavelength, such as Raman spectroscopy, UV–Visible spectroscopy, attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), dynamic light scattering spectroscopy (DLS), Zeta potential spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray photon correlation spectroscopy. Nanostructured materials have a wide application in the food industry as nanofood, nano-encapsulated probiotics, edible nano-coatings and in active and smart packaging.

Biological efficacy of phyto-synthetic silver nanoparticles using ethanol extract of <i>Euphorbia wallichii</i> Hook Rhizome as bio-reductant and surfactant

Purpose: To synthesize silver nanoparticles using rhizome extract (RE) of E. wallichii as a bioreductant and surfactant.Method: RE was used as a bio-reductant for the reduction of Ag+1 (aq.) and as a stabilizing agent for silver nanoparticles (AgNPs). The AgNPs were then characterized by UV-visible spectrophotometer, scanning electron microscopy (SEM), dynamic light scattering spectroscopy (DLS), x-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDS) and infrared (IR) spectroscopy. The antinociceptive potential of AgNPs was evaluated using Eddy’s hot plate. Spasmolytic bioassay was measured in mice via GI charcoal movement test. Anti-leishmanial potency was examined against promastigotes of Leishmania tropica, while antioxidant bioassay was determined using DPPH reduction method.Results: UV-Vis results showed characteristic surface plasmon resonance band from 440 – 460 nm, thus confirming the reducing ability of RE. SEM analysis showed spherical AgNPs with a typical face center cubic (fcc) structure as evidence by their x-ray diffraction (XRD) pattern. The role of RE as a stabilizing agent towards AgNPs was supported by IR and electronic absorption spectral data. Phytochemical investigation of RE confirmed the presence of alkaloids, flavonoids, phenols and glycosides etc. Mice treated with RE-AgNPs exhibited dose-dependent analgesic and spasmolytic effects. RE functionalized AgNPs exhibited promising antileishmanial and antioxidant effects (p < 0.05).Conclusions: RE-AgNPs exhibit substantial spasmolytic and antinociceptive activity, indicating central and peripheral analgesic effects. Thus, the formulation’s antileishmanial and antioxidative effects, indicate that it might be useful for preventing infectious and oxidative stress disorders.Keywords: Euphorbia wallichii, Silver nanoparticles, Antioxidant, Analgesic, Antispasmodic, Antileishmanial

Dynamic Light Scattering Analysis to Dissect Intermediates of SNARE-Mediated Membrane Fusion.

Dynamic light scattering (DLS) spectroscopy provides rapid information on the size distribution of a large number of particles in a mixture. Vesicle sizes change during the merger of lipid bilayers, and DLS analysis can provide rapid, accurate, and non-perturbative quantification of the size distribution of proteoliposomes in SNARE-dependent membrane fusion. In this chapter, we describe the methodologies and reagents used for DLS spectroscopy in a biochemical and biophysical study of SNARE-mediated membrane fusion.

Biosynthesis of Silver Nanoparticles from Protium serratum and Investigation of their Potential Impacts on Food Safety and Control.

Silver nanoparticles play an integral part in the evolution of new antimicrobials against the broad ranges of pathogenic microorganisms. Recently, biological synthesis of metal nanoparticles using plant extracts has been successfully consummated. In the present study, the biosynthesis of silver nanoparticles (AgNPs) was conducted using the leaf extract of plant Protium serratum, having novel ethnomedicinal. The synthesized AgNPs were characterized using UV-Visible spectroscopy, dynamic light scattering spectroscopy (DLS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy. The DLS study revealed the surface charge of the resulted nanoparticles that was highly negative, i.e., −25.0 ± 7.84 mV and the size was 74.56 ± 0.46 nm. The phytochemical and FTIR analysis confirmed the role of water-soluble phyto-compounds for the reduction of silver ions to silver nanoparticles. The potential antibacterial activity of AgNPs was studied against the food borne pathogens viz. Pseudomonas aeruginosa (IC50 = 74.26 ± 0.14 μg/ml), Escherichia coli (IC50 = 84.28 ± 0.36 μg/ml), Bacillus subtilis (IC50 = 94.43 ± 0.4236 μg/ml). The in vitro antioxidant potential of AgNPs was evaluated using 1, 1-diphenyl-2-picryl-hydrazil (IC50 = 6.78 ± 0.15 μg/ml) and hydroxyl radical assay (IC50 = 89.58 ± 1.15 μg/ml). In addition, the cytotoxicity of AgNPs was performed against fibroblast cell line L-929 to evaluate their biocompatibility. The overall results of the present investigation displayed the potential use of P. serratum leaf extract as a good bio-resource for the biosynthesis of AgNPs and their implementation in diverse applications, specifically as antibacterial agent in food packaging and preservation to combat against various food borne pathogenic bacteria along with its pharmaceutical and biomedical applications.

Effect of the Aggregation on the Photophysical Properties of a Blue-Emitting Star-Shaped Molecule Based on 1,3,5-Tristyrylbenzene

In this work we present a study on the effect of the aggregation on the optical properties of star-shaped molecules. We analyzed the modification of the absorption and fluorescent properties of a 1,3,5-tristyrylbenzene core due to the formation of diverse aggregates. The nature of the aggregates in solution was investigated by different spectroscopic techniques such as electronic absorption, steady-state fluorescence, fluorescence anisotropy, time-resolved fluorescence, small-angle X-ray scattering, and dynamic light-scattering spectroscopy. In order to simulate the molecular arrangement of the aggregates, the structure and electronic properties of different clusters formed by stacking of star-shaped molecules were studied by means of density functional theory calculations. The theoretical insight was performed in the gas phase as well as in solution through the polarizable continuum model, and both linear response and state-specific polarization schemes were applied. In the solid state, high quantum yiel...

Characterization of Biomolecular Nanoconjugates by High-Throughput Delivery and Spectroscopic Difference

Nanoparticle conjugates have the potential for delivering siRNA, splice-shifting oligomers or nucleic acid vaccines, and can be applicable to anticancer therapeutics. This article compares tripartite conjugates with gold nanoparticles or synthetic methoxypoly(ethylene glycol)-block-polyamidoamine dendrimers. Interactions with model liposomes of a 1:1 molar ratio of tripalmitin:cholesterol or phospholipid:cholesterol were investigated by high-throughput absorbance, as well as fluorescence difference and cellular luminescence assays. Spectral differences and dynamic light-scattering spectroscopy shifts demonstrated the interaction of conjugates with liposomes. Biological activity was demonstrated by upregulation of gene expression via splice-shifting oligomers, delivery of anti-B-Raf siRNA in cultured human cancer cells or tuberculosis antigen 85B plasmid expression vector in a coculture model of antigen presentation. The data suggests that gold nanoparticles and methoxypoly(ethylene glycol)-block-polyamidoamine dendrimer nanoconjugates may have potential for binding, stabilization and delivery of splice-shifting oligomers, siRNA and nucleic acid vaccines for preclinical trials.