Facile fabrication of Annona squamosa L. seed extract mediated silver nanoparticles challenged against biofilm forming oral pathogens

abstract: Green synthesis of nanoparticles remains to be one of the promising and fascinating approaches in material science research. Although, metal based nanoparticles were shown to possess potent antibacterial effect, challenges pertaining to counter biofilms still exist. In this context, the seed extract of the Annona squamosa fruit was used in fabricating nanosilver and challenged against oral biofilm forming bacteria. The seed extract was used to reduce silver nitrate into nanosilver under optimized laboratory conditions. Characterization studies were performed using spectroscopic and electron microscopic analyzes. Antibacterial study was determined using agar diffusion method and the results validated. Phytochemicals present in the seed extract was found to effectively reduce the metal precursor into nanoform. UV–vis spectral analysis showed typical absorbance (λmax) of AgNPs in the range of 400–450 nm with spherical shaped particles and nanocrystals as revealed from XRD studies. Significant antimicrobial effect toward Streptococcus mutans, Staphylococcus aureus and Escherichia coli in a dose dependent fashion could be achieved on par with control. Adoption of green chemistry principles in fabricating the nanoparticles could help reduce the adverse effects induced from the one synthesized using chemical methods. Their application might be commercialized prior to cytotoxicity studies and in vivo animal models

A waste to worth approach in preparing Ferric vanadate Nanoparticles using peel extract for photocatalytic dye degradation induced by UV light

Photocatalytic decolorization of methylene blue dye (MB) under obvious light has been examined utilizing Ferric Vanadate nanoparticles (FV NPs). The photocatalyst was prepared by using various natural product peel waste (Pomegranate, Apple, Grapes, Orange and Banana (PAGOB)). The physico- and opto-chemical properties of prepared Ferric Vanadate nanoparticles (FV NPs) were determined using X-ray diffraction (XRD) and High-resolution Scanning Electron Microscope (HRSEM). UV–vis spectrophotometric analysis was used to study the rate of photocatalytic degradation of the dye measuring the optical density at regular time intervals. The factors influencing the photocatalytic degradation viz. effect of pH, the concentration of the dye, the quantity of photocatalyst (FV NPs) and the effect of light intensity on the rate of photocatalytic response was investigated under ideal conditions. The outcome demonstrates that degradation achieved 99% under ideal conditions. © 2019 Elsevier Gmb

Bio-fabrication of pigment-capped silver nanoparticles encountering antibiotic-resistant strains and their cytotoxic effect towards human epidermoid larynx carcinoma (HEp-2) cells

Bacterial biomolecule-mediated nanoparticle (NP) synthesis constitutes a reliable, eco-friendly approach that ameliorates green-chemistry principles. In this study, stable silver nanoparticles were synthesized by exposing aqueous silver ions to an extracellular diffusible pigment produced by Pseudomonas aeruginosa (PA6) under optimized laboratory conditions. Spectroscopic and microscopic analyses showed the typical characteristics of silver with an average size of ∼28.30 nm and spherical shape. The particles were polydispersed and showed no definite agglomeration with a zeta potential of -32.3 mV, conferring stability. Antimicrobial studies were carried out using 5, 15, 25 and 50 μg mL-1 concentrations of pcAgNPs, which showed significant antibacterial activity toward clinically important pathogens at all concentrations compared to with the control sample. The bactericidal effect induced by pcAgNPs associated with cell damage was well demonstrated using electron microscopic studies. ROS production was measured using the DCFH-DA method and the oxidative stress was assessed by measuring the reduced glutathione (GSH) levels. Cytotoxicity studies on HEp-2 (Human Epidermoid Larynx Carcinoma) cells exposed to pcAgNPs showed dose-dependent cytotoxic effect with IC50 of 14.8 μg mL-1 compared to with IC50 of 7.38 μg mL-1 for the Vero cell control. Mechanistically, the pcAgNPs activated p53 that induced catalase, leading to apoptosis and DNA fragmentation via a p53 transcriptional pathway and electron transport arrest, which resulted in cell death. This synergistic efficacy of pigment-AgNPs demonstrated excellent antimicrobial and anti-proliferative activities, providing a potential lead for developing a broad-spectrum antibacterial agent and improving the therapeutic modalities targeting carcinoma cells at the gene level. © 2019 The Royal Society of Chemistry

Facile synthesis of silver nanoparticles using Averrhoa bilimbi L and Plum extracts and investigation on the synergistic bioactivity using in vitro models

The bacterial communities (Gram-negative and Gram-positive) form the biofilms which oppose the mode of action of antibiotics and affecting the immune system of the human. These chronic infections related to biofilm are always hard to be cured because of their inherent resistance to both antimicrobial agents and host defense. The present study is devoted to the synthesis of silver nanoparticles (AgNPs) using aqueous extracts of Averrhoa bilimbi leaf and Plum fruit (Prunus bokharensis) and its inhibitory effect on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi. Here, AgNPs) were successfully prepared by green synthesis method obtained by the reduction of silver nitrate into silver ions. The synthesized AgNPs were characterized by UV-Vis Spectroscopy, XRD, FTIR, FESEM-EDAX and DLS analysis. The antimicrobial effects of the two extract were evaluated by the disk diffusion method. The green synthesized AgNPs exhibited good antibacterial activity against both Gram-negative and Gram-positive. They were also analyzed for their significant antibacterial activities against all the test cultures exposed whereas Escherichia coli and Salmonella typhi topped among other test cultures. The anti-proliferative activity of phytochemical mediated synthesis of Ag NPs was investigated for their cytotoxicity in Vero and Human epidermoid larynx carcinoma cell lines (HEp-2) based on their viability using MTT assay. The present study also represents the synergistic bioactivity of silver nanoparticles using in vitro models. © 2019 Sagadevan et al., published by De Gruyter

Mechanistic anticarcinogenic efficacy of phytofabricated gold nanoparticles on human lung adenocarcinoma cells

The present study deals with Plectranthus amboinicus (Lour.), multiple potential herbs perceived as a medicinal and culinary adjunct has been used to fabricate gold (Au) nanoparticles (NPs) in an eco-benign fashion. We have primly reported the antioxidant and anticarcinogenic effects of phytofabricated Au NPs towards lung adenocarcinoma (LAC) cells (A549 cell line) in vitro. The herbal concentrate, size and dosage of Au NPs were the key variables that determined the anticarcinogenic efficacy. Results indicated that the herbal concentrate encompassing flavonoids, alkaloids and polyphenolics aided reduction and stabilisation of Au NPs supported by spectral (λmax @ 550 nm) and quantitative analyses. The Fourier transform-infrared spectra anticipated distinct phenolics and protein frequencies involved in Au NPs capping in the course of fabrication. The manipulated Au NPs of 15 nm size has significantly influenced the radical scavenging (48.1 μg) and proliferation pattern of LAC cells (A549) associated with cytotoxic characteristics and IC50 (Au NPs concentration linked with 50% mortality) defined at 16.3 μg/mL in 48 h. This nanotoxicological prospect on the use of nanomaterials as an anticancer agent would be an alternative for the emerging intrinsic resistance of cells to the drug; a great challenge pertaining to safer environmental and biological outcomes

Nanoformulation of core-shell type hydroxyapatite-coated gum acacia towards the biomedical applications of enhanced bioactivity and controlled drug delivery

In this work, nanospherical hydroxyapatite (HAP) was prepared that has combined properties of controlled drug delivery, biocompatibility, and antibacterial activity to have applications in the biomedical sector. The composite was formed by the sintering of HAP in the presence of Gum acacia (GA) as an emulsifier (at 600 °C) and the composite's physical properties like nucleation, size, shape, crystallinity, and surface area were characterized using spectroscopic, electron microscopic and BET (Brunauer, Emmett and Teller) studies. Typical results of the FTIR study revealed the presence of characteristic phosphate and carbonate groups of HAP and XRD provided the mean crystallite size of GA-HAP in the range of 20–50 nm. The electron micrograph of GA-HAP showed nanorods with a smooth surface interspersed in GA with particle size <50 nm and a change of shape to spheres upon increasing the concentration of GA. The presence of C, O, Ca, and P confirmed through XPS was attributed to the major elemental composition of GA-HAP. Besides, BET studies indicated that the % of GA incorporated seemed to be greatly influenced by the porosity and surface area and this particular property determined the drug loading and leaching efficacy from the GA-HAP matrices when used for drug delivery applications. After bioactivity and leaching studies in the presence of SBF (simulated body fluid), we found that the increased concentration of GA (from 1% to 10%) caused a slowdown and sustained release/burst of the naringenin drug (43% over a 72 h period). Further, antibacterial studies using the clinical strains of bacteria proved that GA-HAP/N (drug-loaded GA-HAP) possessed excellent activity toward S. aureus and E. coli with inhibition zones of 26 mm and 32 mm, respectively. Besides, the biocompatibility and cytotoxicity of GA-HAP/N showed about 90% viability for McCoy cells with no sign of detachment after 72 h of treatment, while Saos-2 cells showed typical inhibition in growth associated with rounding off and detachment, signifying cytotoxicity. This selective toxicity induced by the drug-loaded GA-HAP might find application in drug delivery for precision medicine

Exploring the therapeutic potentials of phytomediated silver nanoparticles formed via Calotropis procera (Ait.) R. Br. root extract

The objective of this work is to develop cost-effective, reliable, and large-scale production of metallic nanoparticles (NPs) by adopting green chemistry principles for industrial applications. In that view, we have studied the phytochemical reducibility of silver nitrate by making use of Calotropis Procera (Ait.) R. Br root extract, and based on its medicinal properties, an attempt was made to evaluate the therapeutic potentials of silver (Ag) NPs containing this plant extract towards the clinical strains of bacteria. The optimization studies on reducing the potentials were done considering the concentration, pH, temperature, and reaction period of both the extract and the metal precursor. The nanoarchitecture elements were interpreted using visual, spectroscopic, and microscopic analyses cohorting the antibacterial potentials towards the clinically significant strains. The antimicrobial activity exercised by these Ag NPs towards 10 different strains of medically important bacteria at a given concentration was proved to be significant. The antimicrobial potential was further validated quantitatively, and the MIC/MBC concentration values were determined. Finally, the cytotoxicity of Ag NPs when tested against the HEPK cell line indicated that the metal-phytochemical moiety exhibited the maximum therapeutic efficacy and thereby paving the way for the development of disruptive technologies in the field of nanomedicine