Comparative Study on Inhibition of Pancreatic Cancer Cells by Resveratrol Gold Nanoparticles and a Resveratrol Nanoemulsion Prepared from Grape Skin

Resveratrol, a phenolic compound possessing vital biological activities such as anti-cancer, is present abundantly in grape skin, a waste produced during the processing of grape juice. The objectives of this study were to prepare resveratrol-gold nanoparticles and a resveratrol nanoemulsion from grape skin and study their inhibition effects on pancreatic cancer cells BxPC-3. The spherical-shaped citrate gold nanoparticles (GNPs) and resveratrol-gold nanoparticles (R-GNPs) were, respectively, prepared with a surface plasmon resonance peak at 528 and 538 nm, mean particle size of 20.8 and 11.9 nm, and zeta-potential at −32.7 and −66.7 mV, by controlling an appropriate concentration of citrate/resveratrol and gold chloride as well as stirring time and temperature. The resveratrol nanoemulsion, composed of soybean oil, Tween 80, and sucrose fatty acid ester in glycerol and water, possessed a high storage stability with a mean particle size of 14.1 nm, zeta-potential of −49.7 mV, and encapsulation efficiency of 95.5%. An antiproliferation study revealed that both R-GNPs and resveratrol nanoemulsion could effectively inhibit the growth of pancreatic cancer cells BxPC-3, with the latter showing a higher inhibition effect. Western blot analysis implied that both can down-regulate expressions of cyclin A, cyclin B, CDK1, and CDK2 and up-regulate expressions of p53 and p21, accompanied by enhancing cytochrome C expression, decreasing BcL-2 expression, increasing Bax expression, and leading to the elevation of caspase-8, caspase-9, and caspase-3 activities for cell apoptosis execution. Future research is needed to study the inhibition of pancreatic tumors in vivo by R-GNPs and resveratrol nanoemulsions.

Ecological and sustainable synthesis of silver nanoparticles from alcoholic extract of Eucalyptus globulus: Evaluation of alcoholic solvent influence (70° and 96°)

The present study provides an ecological and sustainable methodology for obtaining nanostructured material from Eucalyptus globulus leaf extract, as a potential value-added alternative and a contribution to circular economy. Silver nanoparticles (NP Ag) were synthesized, through the reducing action of the alcoholic extracts of eucalyptus on the precursor silver nitrate (AgNO3) evaluating the influence of alcoholic solvent (70 ° and 96 °) and pH in the synthesis. The silver colloids obtained were evaluated by UV-vis spectrophotometry, which shows the formation of nanoparticles through the plasmon resonance peak; showing that for pH values 9.9 and 10 with alcohol extract of 70 ° and 96 ° respectively, silver nanoparticles with plasmon resonance peaks at 410 nm and 412.5 nm are obtained. While for pH values 3.86, 11.8 (96°) and 4.7, 8.2 (70°) nanoparticles with higher polydispersity and in a lower proportion are obtained. The results suggest that the alcoholic extracts of eucalyptus can act as reducing agents and that the optimum pH value for the synthesis of silver nanoparticles corresponds to 10.

Study of plasmonic properties of copper monosulfide nanoparticles depending on their dielectric constant

The object of research is plasmonic properties copper of monosulfide nanoparticles. One of the most problematic areas is that there is still no unambiguous answer to which main copper monosulfide nanoparticles parameters have a decisive effect on their resonance absorption, scattering or electric field enhancement. It is necessary to study the plasmonic properties of copper monosulfide nanoparticles depending on their main parameter, namely the dielectric constant. The principle of dipole equivalence and Mee-Gans theory for the modeling of the optical nanoparticle characteristics is used. It is found that dielectric constant is a crucial parameter determining the resulting optical response of such nanoparticles. The surrounding medium refractive index affects the position and magnitude of the nanoparticles maximum plasmonic absorption. The nonspherical nanoparticles are characterized by two plasmon peaks corresponding to transverse and longitudinal localized surface plasmon resonance if the ratio between the axes is higher than 1.5. The ellipsoidal nanoparticles exhibit higher sensitivity to changes in the refractive index of the surrounding medium in comparison to the spherical ones. The obtained research results are primarily the basis for further comprehensive research of plasmonic copper monosulfide nanoparticles for their specialized applications. Second, knowledge of the influence of the nanoparticle dielectric constant on their resulting spectral characteristics allow tuning of the localized surface plasmon resonance peak position in a wide wavelength range, from 500 to 1200 nm, using the nanoparticle synthesis technique. Thus, the material under study is promising for sensor applications in a wide spectral range.

Myco-Fabricated Gold Nanoparticles from Aspergillus Tamarii MTCC5152, its Characterization and Dye Biodegradation

This work was initiated to investigate the myco-fabrication of gold nanoparticles (AuNPs) using a fungal strain, Aspergillus tamarii 5152 (A. tamarii MTCC 5152). The biosynthesized gold nanoparticles were characterized by visual observation, and using UV-Vis and FTIR spectroscopy, DSC, TGA, Zeta-potential, DLS and SEM analyses. NADH-dependent cofactor analysis and photocatalysis assays were carried out for NADH-dependent AuNPs biosynthesis and dye degradation ability. A maximum surface plasmon resonance peak for the AuNPs was recorded at 535 nm, followed by the identification of protein capping effect of the extract by FTIR spectroscopy. The average size (Z) of the nanoparticles observed was 39.15 nm, while SEM images showed crystallized rod-shaped structures ranging from 55-91 nm. A negative zeta potential of 10.5 mV showed repulsion between the nanoparticles, which indicates the stabilizing power of the fungal extract. Further, it was observed that NADH acts as a cofactor for the nanoparticle biosynthesis. The AuNPs were found to degrade crystal violet dye by 63%. From this study, it can be understood that the process of fungal mediated biosynthesis of AuNPs by A. tamarii MTCC 5152 is simple, less expensive, and could be utilized for bioremediation of toxic dye accumulation.

Effects of synthesis conditions and storage on silver nanospheres chemically reduced by mulberry leaf extracts

Silver (Ag) nanospheres were chemically reduced from 1 mM silver nitrate (AgNO3) solutions using mulberry (Morus alba Linn.) leaf extracts. The increase of pH in the synthesis from 9 to 13 modified the surface plasmon resonance peak in UV-Vis spectra relating to the particle diameter around 20 nm. Smaller nanoparticles were obtained from the syntheses at pH 7.4-7.7 and their density was slightly increased with the increase in synthesis temperature from 25 °C to 90 °C. The particle size was increased with increasing AgNO3 concentration from 0.1 to 0.5 M but the mixed phases were obtained from the 0.5 M AgNO3 precursor. After storing for 10 months at room temperature, the nanosuspensions remained without Ag sediment but their colors had significantly changed due to particle agglomerations. The colors were characterized by the smartphone colorimetry according to the RGB, CIE space, as well as chroma and hue angle. Based on the chroma and CIE b* values, the effect of synthesis pH in the stored nanosuspensions was comparable to that before the storage. Although the temperature had only moderate effects, nanosuspensions synthesized at 25 °C, 80 °C, and 90 °C were clearly distinguished by the hue and CIE b* values.

Facile and Novel Synthesis of Spiky Gold Nanoparticles as an Efficient Antimicrobial Agent against Pseudomonas Aeruginosa

Aims: The study aims to develop advanced antibacterial agents as nanoparticles instead of antibiotics due to the emergence of antimicrobial resistance. Background: Pseudomonas aeruginosa is capable of causing many diseases, including severe bacterial pneumonia. There is a need for an efficient antibacterial agent to kill these pathogens. Objective: The objective of the study is to synthesize advanced antibacterial agents as nanoparticles for biomedical applications that can play a vital role in killing Gram-negative bacteria (Pseudomonas aeruginosa). Method: A novel fabricated growth of hydrophilic spiky gold nanoparticles (SGNPs) via reduction method is reported. Results: The surface plasmon resonance peak of the synthesized SGNPs was tuned under the near-infrared range. The SGNPs have anisotropic and spiky morphology with 68 nm size and -58 mV surface charge. They are pure, possessing adsorption similar to the organic material. Pseudomonas aeruginosa treated with synthesized SGNPs showed 60% bacterial death at the concentration of 100 μM. Conclusion: This work consists of the novel synthesis of SGNPs via a safe and simple reduction method. The synthesized SGNPs exhibit strong antibacterial activity against the Gram-negative bacteria Pseudomonas aeruginosa measured using a microplate assay test. The result showed that these SGNPs are ideal for biomedical applications.

Green synthesis of silver nanoparticles from Catunaregam tomentosa extract

Silver nanoparticles (AgNPs) have been widely used in many fields (e.g., sensors, medical supplies, food, cosmetics, medicines, etc.) due to their unique properties such as optical property, antibacterial property, and high conductivity. AgNPs are normally synthesized by chemical, physical, or biological methods. Among these methods, biological synthesis or green synthesis of AgNPs has drawn much attention since it is an easy and environmental-friendly method. Herein, AgNPs synthesized using Catunaregam tomentosa extracts were studied. The extracts obtained from different C. tomentosa fruit were found to be blue, green, and brown. It was found from the foam test and IR spectra that all extracts (blue, green, and brown extracts) contained saponins. According to the DPPH assay, the blue and the green extracts had the antioxidant activities of 84.47 ± 12.13 and 47.66 ± 2.86 mg ascorbic acid equivalent/g of C. tomentosa powder, respectively. This showed that the blue and the green extracts could act as reducing agents in AgNPs synthesis. The successfully synthesized AgNPs using C. tomentosa extracts showed the surface plasmon resonance peak at 400 nm corresponding to literatures. The particle sizes and zeta potential values measured by dynamic light scattering also indicated the size stability of the synthesized AgNPs during seven-day period with no significant difference (P > 0.05).

Synthesis of Silver and Gold Nanoparticles from Rumex roseus Plant Extract and Their Application in Electrochemical Sensors

The room-temperature synthesis of silver (AgNPs) and gold (AuNPs) nanoparticles from aqueous solution of AgNO3 and HAuCl4 respectively, using Rumex roseus (RR) plant extract as a reducing agent, is reported here for the first time. The nanoparticles obtained were characterized by UV-Vis spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS). The formation of nanoparticles with spherical-shaped morphology was verified by TEM and confirmed by UV-Vis spectroscopy through the analysis of Ag and Au plasmon resonance peak and DLS measurements. New electrochemical sensors have been developed by employing the synthesized Ag and Au nanoparticles as modifiers of glassy carbon electrode (GCE) and screen-printed carbon electrode (SPCE), respectively. The AgNPs-modified GCE was investigated for the electrochemical determination of hydrogen peroxide (H2O2). Further enhancement of electrochemical performances was obtained using a nanocomposite made of AgNPs and reduced graphene oxide (rGO)-modified GCE. The AuNPs-SPCE sensor was instead tested in the electrochemical sensing of riboflavin (RF). To our knowledge, this is the first paper reporting Rumex roseus plant extract as a source for the synthesis of metal nanoparticles and their use for developing simple, sensitive and reliable electrochemical sensors for H2O2 and RF.

Antimicrobial activities of biosynthesized silver nano particles from leaves extract of some medicinal plants

The antimicrobial activity of biosynthesized silver nanoparticles (AgNPs) from the leaves of four medicinal plants, Carica papaya (CP), Moringa oleifera (MO), Mangifera indica (MI) and Garcinia kola (GK) were assessed against selected gram positive and gram-negative bacteria. Method of synthesis of nanoparticles utilized was the eco-friendly Bio-based method using plant leaves extract as reducing and stabilizing agents. Two different ratios for each plant extract and silver nitrate (1:1 and 1:2) respectively were used. Particle characterization was carried out using visual inspection and UV-Vis spectrophotometry. Antimicrobial activity was assessed using agar diffusion method. Visual inspection revealed gradual color change from golden yellow to dark brown, confirming nanoparticles formation. The surface plasmon resonance peak was between 416 and 438 nm for the silver nanoparticles. The minimum inhibitory concentration ranged from 3.125 - 12.5µg/ml. In conclusion, all four biogenic silver nanoparticles have reasonable antimicrobial activity with ratio 1:2 being more potent.

BIOSYNTHESIZED SILVER NANOPARTICLES USING CATHARANTHUS ROSEUS AND THEIR ANTIBACTERIAL EFFICACY IN SYNERGY WITH ANTIBIOTICS; A FUTURE ADVANCEMENT IN NANOMEDICINE

Objective: This research work develops an approach to synthesize silver nanoparticles (AgNPs) by reduction of leaf extract of Catharanthus roseus plant. This study produces synthesized nanoparticles that have process-controlled attributes which make their antibiotic action highly efficient. These attributes include smaller size, proper morphology, uniform dispersion, metal ion content, and formation of functional groups. By optimizing the reduction process parameters, AgNPs gain the desired properties. Methods: The biosynthesis of AgNPs process was performed using reaction of 10% (w/v) C. roseus leaf extract with AgNO3. The optimum conditions and concentration used for synthesis of nanoparticles were: 1 mM AgNO3, pH 5, and temperature 80°C with an incubation time of 72 h. All the above parameters were analyzed by ultraviolet-visible spectrophotometer with the surface plasmon resonance peak obtained at 440 nm. Results: Various characterization techniques were performed, namely, scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, photoluminescence study, X-ray diffraction spectroscopy, Fourier transform infrared, dynamic light scattering, and atomic force microscopy. The results obtained from characterization confirmed the spherical morphology of the nanoparticles with size between 50 and 87 nm. In the current investigation, the antimicrobial activity of biosynthesized AgNPs was also determined using minimum inhibitory concentration and zone of inhibition methods against six different bacteria at different doses of AgNPs (100, 150, and 200 μg/ml) alone and also in combination with antibiotic-streptomycin. Conclusion: The results revealed that high concentration of AgNPs inhibits the bacterial growth. Furthermore, AgNPs revealed much stronger antibacterial action in synergy with streptomycin against antibiotic-resistant bacteria.