Effect Of Biosynthesized Silver Nanoparticles Research Articles

The Effect of Bio-Synthesized Silver Nanoparticles on Germination, Early Seedling Development, and Metabolome of Wheat (Triticum aestivum L.).

Changes in the metabolome of germinating seeds and seedlings caused by metal nanoparticles are poorly understood. In the present study, the effects of bio-synthesized silver nanoparticles ((Bio)Ag NPs) on grains germination, early seedlings development, and metabolic profiles of roots, coleoptile, and endosperm of wheat were analyzed. Grains germinated well in (Bio)Ag NPs suspensions at the concentration in the range 10–40 mg/L. However, the growth of coleoptile was inhibited by 25%, regardless of (Bio)Ag NPs concentration tested, whereas the growth of roots gradually slowed down along with the increasing concentration of (Bio)Ag NPs. The deleterious effect of Ag NPs on roots was manifested by their shortening, thickening, browning of roots tips, epidermal cell death, progression from apical meristem up to root hairs zone, and the inhibition of root hair development. (Bio)Ag NPs stimulated ROS production in roots and affected the metabolic profiles of all tissues. Roots accumulated sucrose, maltose, 1-kestose, phosphoric acid, and some amino acids (i.e., proline, aspartate/asparagine, hydroxyproline, and branched-chain amino acids). In coleoptile and endosperm, contrary to roots, the concentration of most metabolites decreased. Moreover, coleoptile accumulated galactose. Changes in the concentration of polar metabolites in seedlings revealed the affection of primary metabolism, disturbances in the mobilization of storage materials, and a translocation of sugars and amino acids from the endosperm to growing seedlings.

Selective Toxicity of Biosynthesised Silver Nanoparticles on MCF-7 and MDA MB-231 Breast Cancer Cell Lines

Biosynthesized nanoparticles have many applications in the field of biopharmaceutics due to its high surface to volume ratio, less toxicity and synergistic effects with conjugated biomolecules. This study reports the selective cytotoxicity effect of biosynthesized silver nanoparticles (AgNPs) on breast cancer cell lines MCF-7 and MDA MB-231. AgNPs were synthesized using an aqueous extract of Mollugo cerviana species of plant and characterized using UV–visible spectroscopy, zeta potential analyser, SEM, FT-IR, XRD, and EDX. An UV-visible spectrum of the extract shows the surface plasmon resonance peak of AgNPs at 420 nm. SEM analysis results confirm the sphericity of the AgNPs whose size isin the range of 50 – 100 nm. The zeta potential value of -27 mV indicates the stability of the biosynthesized AgNPs. Dose-Dependent cytotoxicity was observed against human breast cancer cells lines MCF-7 and MDA MB-231. The inhibitory concentrations (IC50) are 21.53 μg/mL and 25.52 μg/mL respectively. There was no significant toxicity against Vero cells below 100 μg/mL concentration of AgNPs. The data obtained in the study reveal the potential therapeutic value of biogenic silver nanoparticles in cancer treatment and further studies are required to elucidate the mechanism of selective activity of biosynthesized AgNPs on cancer cells.

Phytostimulatory effect of silver nanoparticles (AgNPs) on rice seedling growth: An insight from antioxidative enzyme activities and gene expression patterns

The knowledge on the mode of action, biocompatibility and ecological tolerance of silver nanoparticles (AgNPs) is gradually accumulating over the years with contradictory findings. Most of the studies indicated the toxic impact of AgNPs on plant growth and development, where induction of oxidative stress was considered to be one of the causal factors. The present study demonstrates the phytostimulatory effect of bio-synthesized silver nanoparticles (AgNPs) during seed germination and seedling growth of rice (Oryza sativa L., cv. Swarna) under in vitro condition. All the tested concentrations of AgNPs (10, 20, 40 ppm) promote both the shoot and root growth which was evident from the increased length and biomass of the seedlings. Exposure to AgNPs also significantly increased the chlorophyll a and carotenoid contents. The content and the pattern of distribution of phenolic metabolites among the different treatments are indicative of non-toxic impact of AgNP mimicking mild or no stress to the seedlings. Growth stimulation of rice seedlings by AgNPs was further supported by a low level of reactive oxygen species (ROS) concomitant with decreased amount of lipid peroxidation and H2O2 content, compared to control. In order to unravel the stimulatory impact of AgNPs on rice seedling growth, the present study also describes the AgNPs induced changes in antioxidative enzyme activity and related gene expression levels. Elevated levels of catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) activities were recorded in all the AgNPs treated seedlings with improved growth. The activity of superoxide dismutase (SOD) was not significantly altered at low concentration of AgNPs. It appears that enzymes of ascorbate cycle, APX and GR are more active in ensuring protection against oxidative damage than SOD. There was significant up-regulation of CAT and APX gene expressions in seedlings exposed to AgNPs, whereas the expression level of CuZnSOD gene was decreased gradually with an increase in the concentration of AgNPs. The antioxidant enzyme activities and gene expression patterns coupled with the levels of H2O2 and lipid peroxidation indicates that the efficiency of redox reactions was increased in the presence of AgNPs and that accelerates the seedling growth.

Effect of biosynthesized silver nanoparticles on native soil microflora via plant transport during plant-pathogen-nanoparticles interaction.

In this study, the interaction of biosynthesized silver nanoparticles (BSNP) with native soil via plant transport was assessed in model pathosystem of Arabidopsis thaliana and Alternaria brassicicola. Foliar application of 5μg/mL of BSNP reduced number of spores of fungi to 2.2×105 from 7×105, while numbers of lesions got reduced to 0.9/leaf in treated plants compared to 2.9/leaf in pathogen-infected plant without altering soil pH, electric conductivity, soil organic carbon and soil microbial biomass carbon. Soil enzyme activities including dehydrogenase, acid and alkaline phosphatase, urease, β-glucosidase and protease did not alter significantly in BSNP-treated plants compared to control plants. Application of BSNP did not alter the number of cultivable bacteria, fungi and actinomycetes. Effect of BSNP on uncultured bacterial diversity was measured by DGGE analysis which revealed similar banding pattern in all different treatments except in A. brassicicola-infected (AB) and A. brassicicola-infected plants treated with silver nanoparticles (AB+BSNP) after 120days. Although AB-infected plants exhibited a decrease in bacterial diversity, treatment of AB+BSNP after 120days demonstrated maximum bacterial diversity. McIntosh, Shannon, and Simpson diversity indices were calculated based on carbon source utilization pattern by BIOLOG analysis, revealing no significant difference among all treatments in different time intervals. BSNPs have the potential to act as strong antimicrobial agent for plant disease management without altering the native soil microflora.

Antigenotoxic effect of green-synthesised silver nanoparticles from Ocimum sanctum leaf extract against cyclophosphamide induced genotoxicity in human lymphocytes—in vitro

The present study was aimed to identify the antigenotoxic effect of bio-synthesised silver nanoparticles (SNP) of Ocimum sanctum leaf extract against cyclophosphamide (CP). We tested the antigenotoxic effect of bio-synthesized silver nanoparticles of O. sanctum leaf extract on human lymphocytes against CP by using chromosomal aberration assay (CAA). Silver nanoparticles was first synthesized from fresh leaf extract of O. sanctum and characterised. Their quality was checked by XRD technique and morphology by SEM. Three different doses of the bio-synthesised SNPs namely, 50, 100 and 200 μl/ml were selected and CP (100 μg/ml) was used as a positive control for CAA. CP administration to human lymphocytes culture caused reduction in mitotic index (MI) and increase in chromosomal damages. The three doses (50, 100 and 200 μl/ml) significantly (P < 0.005) reduced the chromosomal damages by CP and there was increase in MI. The biological way of synthesising SNPs has advantages like cost effectiveness and eco-friendly. Also the bio-synthesised SNPs of O. sanctum leaf extract was found to be an powerful genoprotectant. Furthermore works are to be carried out in future to find the extract mechanism of its genoprotective nature.