Protein Corona Mediated Uptake and Cytotoxicity of Silver Nanoparticles in Mouse Embryonic Fibroblast

Medical applications of nanoparticles (NPs) require understanding of their interactions with living systems in order to control their physiological response, such as cellular uptake and cytotoxicity. When NPs are exposed to biological fluids, the adsorption of extracellular proteins on the surface of NPs, creating the so‐called protein corona, can critically affect their interactions with cells. Here, the effect of surface coating of silver nanoparticles (AgNPs) on the adsorption of serum proteins (SPs) and its consequence on cellular uptake and cytotoxicity in mouse embryonic fibroblasts are shown. In particular, citrate‐capped AgNPs are internalized by cells and show a time‐ and dose‐dependent toxicity, while the passivation of the NP surface with an oligo(ethylene glycol) (OEG)‐alkanethiol drastically reduces their uptake and cytotoxicity. The exposure to growth media containing SPs reveals that citrate‐capped AgNPs are promptly coated and stabilized by proteins, while the AgNPs resulting from capping with the OEG‐alkanethiol are more resistant to adsorption of proteins onto their surface. Using NIH‐3T3 cultured in serum‐free, the key role of the adsorption of SPs onto surface of NPs is shown as only AgNPs with a preformed protein corona can be internalized by the cells and, consequently, carry out their inherent cytotoxic activity.     

Silver nanoparticles and silver salt (AgNO3) elicits morphogenic and biochemical variations in callus cultures of sugarcane

The research work was arranged to check the role of AgNPs and silver ions on callus cells of sugarcane (Saccharum spp. cv CP‐77,400). AgNPs were synthesized chemically and characterized by UV‐Vis spectra, XRD and SEM. AgNPs and silver ions were applied in various concentrations (0, 20, 40, 60 ppm) to sugarcane calli and the induced stress was characterized by studying various morphological and biochemical parameters. AgNPs and silver ions treatments produced high levels of malondialdehyde, proline, proteins, TP and TF contents. Similarly, CAT, SOD and POX activity was also significant in both treatments. The lower concentration of AgNPs and silver ions (20 ppm) provided maximum intracellular GSH level. This work mainly showed effects of AgNPs and silver ions on sugarcane calli in terms of morphological aberrations and cell membrane damage due to severe oxidative stress and production of enhanced levels of enzymatic and non‐enzymatic antioxidants as self‐defence to tolerate oxidative stress by scavenging reactive oxygen species. These preliminary findings will provide the way to study ecotoxicity mechanism of the metal ions and NPs in medicine industry and in vitro toxicity research. Furthermore, silver ions alone and their chemically synthesised AgNPs can be used for various biomedical applications in future.Inspec keywords: nanoparticles, biomedical materials, X‐ray diffraction, scanning electron microscopy, silver, molecular biophysics, toxicology, enzymes, visible spectra, nanofabrication, ultraviolet spectra, microorganisms, nanotechnology, plant diseases, crops, agricultural safetyOther keywords: silver nanoparticles, silver salt, scanning electron microscopy, total flavonoid contents, callus cultures, sugarcane cultivation, Saccharum spp, UV‐visible spectroscopy, X‐ray diffraction analysis, malondialdehyde, proline, proteins, total phenolic content, catalase, superoxide dismutase, peroxidases activities, scavenging reactive oxygen species, biomedical applications, microbial disease resistance, AgNO₃ , Ag     

Genotoxicity tests of poly(styrene-co-maleic anhydride)-coated silver nanoparticles in vivo and in vitro

Nanosilver is thought to hold potential for use in medical materials. The safety of newly developed poly(styrene-co-maleic anhydride)-coated silver nanoparticles (SMA-AgNPs) requires investigation. In this study, three in vitro and in vivo experiments for investigating genetic toxicity–the Ames test, a micronucleus assay, and a chromosome aberration test–were conducted. Results from the Ames testing showed SMA-AgNPs to have a negative effect, either with or without S9 metabolism. In addition, SMA-AgNPs increased the number of reticulocytes and micronuclei in reticulocytes at 48 and 72 h after treatment. Indeed, SMA-AgNPs induced significant changes in the chromosomal aberration rate in CHO-K1 (Chinese hamster ovary cell clone K1) cells. In conclusion, SMA-AgNPs did cause DNA damage in terms of chromosomal aberration and may have a potential genotoxic effect in certain applications.     

Cytotoxicity and Immunological Response of Gold and Silver Nanoparticles of Different Sizes

The immunological response of macrophages to physically produced pure Au and Ag nanoparticles (NPs) (in three different sizes) is investigated in vitro. The treatment of either type of NP at ≥10 ppm dramatically decreases the population and increases the size of the macrophages. Both NPs enter the cells but only AuNPs (especially those with smaller diamter) up‐regulate the expressions of proinflammatory genes interlukin‐1 (IL‐1), interlukin‐6 (IL‐6), and tumor necrosis factor (TNF‐α). Transmission electron microscopy images show that AuNPs and AgNPs are both trapped in vesicles in the cytoplasma, but only AuNPs are organized into a circular pattern. It is speculated that part of the negatively charged AuNPs might adsorb serum protein and enter cells via the more complicated endocytotic pathway, which results in higher cytotoxicity and immunological response of AuNPs as compared to AgNPS.     

Influences of gold and silver nanoparticles in loop-mediated isothermal amplification reactions

Loop-mediated isothermal amplification (LAMP) performed with protein DNA polymerase Bst and DNA chains was influenced by nanoparticles in different ways. The effects of different concentrations of gold nanoparticles (AuNPs) with diameters 10 and 20?nm and silver nanoparticles (AgNPs) 1–10?nm in diameter on the amplification of the pR72H gene of Vibrio parahaemolyticus were investigated. AuNPs with a diameter of 10?nm in 0.6–60?nM concentration accelerated initiation of the LAMP reaction, 3?nM AuNPs reduced the reaction time by about 10?min, whereas 20?nm AuNPs did not, although neither size increased the yield after 60?min. AgNPs inhibited the LAMP reaction both in speed and yield at concentrations of 0.6–60?nM; the yield of amplification was reduced by 50% and 80% for 12 and 60?nM, respectively, after reaction for 1?h. This indicated that strong bactericidal effects of silver are also observed in its nanoparticles. The molecular mechanism of AuNPs and AgNPs in LAMP needs to be explored further, although their size-related electronic, magnetic and optical properties, as well as their ability to affect protein denaturation, or hydrophilic/hydrophobic effects may be involved.     

Biosynthesis,characterisation and antimicrobial activity of silver and gold nanoparticles by Dolichos biflorus Linn seed extract

The bioreduction method employed for the synthesis of colloidal AgNPs and AuNPs is reported here. Methanolic and aqueous extracts of Dolichos biflorus Linn seed was used as the bio-reducing agent. The structural and morphological aspects of the synthesised metal nanoparticles were investigated using X-ray diffraction (XRD), energy-dispersive spectroscopy (EDX), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD, revealed crystalline nature of the synthesised particles, UV–vis spectrophotometric analysis showed characteristic absorption peak for both AgNPs and AuNPs. EDX analysis confirmed the presence of elemental silver and gold particles and the average size and morphology were determined by SEM and TEM. The synthesised AgNPs exhibited good antibacterial potential whereas AuNPs showed poor activity against human pathogenic, gram-positive bacteria such as Staphylococcus aureus, Bacillus subtilis and gram-negative bacteria, such as Escherichia coli, Pseudomonas aeruginosa.     

Speciation analysis of silver nanoparticles and silver ions in antibacterial products and environmental waters via cloud point extraction-based separation

The rapid growth in commercial use of silver nanoparticles (AgNPs) will inevitably increase silver exposure in the environment and the general population. As the fate and toxic effects of AgNPs is related to the Ag(+) released from AgNPs and the transformation of Ag(+) into AgNPs, it is of great importance to develop methods for speciation analysis of AgNPs and Ag(+). This study reports the use of Triton X-114-based cloud point extraction as an efficient separation approach for the speciation analysis of AgNPs and Ag(+) in antibacterial products and environmental waters. AgNPs were quantified by determining the Ag content in the Triton X-114-rich phase with inductively coupled plasma mass spectrometry (ICPMS) after microwave digestion. The concentration of total Ag(+), which consists of the AgNP adsorbed, the matrix associated, and the freely dissolved, was obtained by subtracting the AgNP content from the total silver content that was determined by ICPMS after digestion. The limits of quantification (S/N = 10) for antibacterial products were 0.4 μg/kg and 0.2 μg/kg for AgNPs and total silver, respectively. The reliable quantification limit was 3 μg/kg for total Ag(+). The presence of Ag(+) at concentrations up to 2-fold that of AgNPs caused no effects on the determination of AgNPs. In the cloud point extraction of AgNPs in antibacterial products, the spiked recoveries of AgNPs were in the range of 71.7-103% while the extraction efficiencies of Ag(+) were in the range of 1.2-10%. The possible coextracted other silver containing nanoparticles in the cloud point extraction of AgNPs were distinguished by transmission electron microscopy (TEM), scanning electron microscopy (SEM)- energy dispersive spectroscopy (EDS), and UV-vis spectrum. Real sample analysis indicated that even though the manufacturers claimed nanosilver products, AgNPs were detected only in three of the six tested antibacterial products.     

Biosynthesis of silver nanoparticles using sun-dried mulberry leaf

The biosynthesis of silver nanoparticles (AgNPs) has been successfully conducted by reduction of silver nitrate with sun-dried mulberry leaf. Such AgNPs have been characterized by UV-visible spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM). The results showed that such dispersed, uniform and spherical AgNPs would not aggregate under high-concentration NaCl solution and have good antibacterial activity. It was suggested that the polyol components (such as polyhydroxylated alkaloids) and protein residues of mulberry leaf should be mainly responsible for the stabilization of AgNPs. Such AgNPs produced by the environmentally friendly method have the potential for use in antibacterial and medical applications.     

Silver nanoparticles-doped collagen–alginate antimicrobial biocomposite as potential wound dressing

Development of novel wound dressing with potent antibacterial activity is crucial for wound healing and tissue regeneration. In this work, we aim to prepare silver nanoparticles (AgNPs)-doped collagen–alginate (CA–AgNPs) biocomposite, which may possess antibacterial activity and be used as wound dressing. AgNPs were synthesized using NaBH₄ as reducing agent and polyvinyl pyrrolidone as stabilizing agent. The formation of the AgNPs was confirmed by ultraviolet–visible spectrophotometer and transmission electron microscopy. Then, the as-prepared AgNPs were mixed with sodium alginate and collagen to obtain CA–AgNPs biocomposite. The CA–AgNPs biocomposite was fully characterized to verify the presence of AgNPs in the biocomposite. In vitro cytotoxicity assay illustrated that the CA–AgNPs biocomposite possessed negligible cytotoxicity at low AgNPs concentration. Furthermore, the antibacterial activity of the CA–AgNPs biocomposite was assessed against Staphylococcus aureus and Escherichia coli through agar diffusion method. Inhibition zone indicated that CA–AgNPs biocomposite possessed much higher antimicrobial activity than that of CA biocomposite, which strengthened with the increase in the AgNPs contents. Taken together, our finding suggested that the CA–AgNPs biocomposite showed strong potential as wound dressing.     

Biofilm reduction,cell proliferation,anthelmintic and cytotoxicity effect of green synthesised silver nanoparticle using Artemisia vulgaris extract

Infectious diseases are caused by etiological agents. Nanotechnology has been used to minimise the effect of clinical pathogens which have resistance to antibiotics. In current research synthesis, characterisation and biological activities of green synthesised nanoparticles using Artemisia vulgaris extract have been done. The characterisation of AgNPs was carried out using Fourier transform infrared spectroscopy, UV‐Vis spectrophotometry, and scanning electron microscopy. Anti‐biofilm, cell viability, antibacterial, brine shrimp lethality, and deoxyribonucleic acid protection effects have been screened. UV‐Vis spectra showed the absorption peak of synthesised nanoparticles at 400 nm. FT‐IR indicated the involvement of the functional group in the preparation of AgNPs. SEM showed the spherical shape of AgNPs with 30 nm diameter. Biological screening results revealed the antibacterial effect against clinical bacterial pathogens. Biofilm reduction and cell viability assay also supported the antibacterial effect. Cytotoxicity effect was recorded as 100% at 200 μg/ml through brine shrimp lethality assay. Protein kinase inhibition zones recorded for AgNPs (16 mm bald) compared with A. vulgaris extract (11 mm bald). It has been concluded that green synthesised AgNPs are more effective against infectious pathogens and could be used as a potential source for therapeutic drugs.Inspec keywords: cellular biophysics, toxicology, silver, nanoparticles, nanomedicine, diseases, microorganisms, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, enzymes, molecular biophysicsOther keywords: biofilm reduction, cell proliferation, anthelmintic effect, cytotoxicity effect, green synthesised silver nanoparticle, Artemisia vulgaris extract, infectious diseases, aetiological agents, Fourier transform infrared spectroscopy, UV‐Vis spectrophotometry, scanning electron microscopy, SEM, antibiofilm, cell viability, brine shrimp lethality, deoxyribonucleic acid protection effects, AgNP, cytotoxicity, protein kinase inhibition zones, therapeutic drugs     

Mechanisms of antibacterial activity and stability of silver nanoparticles grown on magnetron sputtered TiO<Subscript>2</Subscript> coatings

Nanomaterials with high stability and efficient antibacterial activity are of considerable interest. The preparation of silver nanoparticles (AgNPs) on titania coatings and their effective antibacterial activity against Staphylococcus aureus ATCC 6538 were reported. Titanium dioxide (TiO₂) coatings with AgNPs were prepared on Si wafers using the reactive magnetron sputtering method. The surface topography of AgNPs/TiO₂ coatings imaged using scanning electron microscopy revealed that the size and surface density of AgNPs grown by the photoreduction of silver ions were dependent on the concentration of AgNO₃ in the primary solution and the time of TiO₂ exposure to UV illumination. Evaluation of the antimicrobial properties and surface analysis before and after the biological test of AgNPs/TiO₂ coatings indicates their high antimicrobial stability and durability. Furthermore, the interdependence between the concentration of released silver and bacterial growth inhibition was demonstrated. In addition, direct contact killing and released silver-mediated killing have been proposed as a bactericidal mechanism of action of tested coatings with AgNPs.     

Safe and Effective Ag Nanoparticles Immobilized Antimicrobial NanoNonwovens

Silver nanoparticles (AgNPs) with large surface‐to‐volume ratio have been widely studied as a valuable material for their strong antimicrobial effect. However, the practical applications of AgNPs in health care and water purification are often hampered by the concern of their toxicity and possibility of introduction of secondary pollution. Here, we present a novel strategy to produce a safe and effective antimicrobial nanononwoven material by immobilizing AgNPs on a rigid polymer nanofibrous matrix through simple co‐electrospinning of pre‐prepaired AgNPs and polystyrene (PS). Distribution of the AgNPs on the surface of PS fibers was achieved by tuning fiber diameters during electrospinning. Atomic force microscopy (AFM) analysis revealed that the AgNPs distributed at the fiber surface were still covered by a layer of polymer, which inhibited their antimicrobial activity. UV/ozone treatment was thus employed to degrade the polymer coating without loosening the AgNPs, resulting in an active antimicrobial nonwoven against Gram‐positive Staphylococcus xylosus. The mechanism based on cellular uptake of silver ions via close contact to the surface of AgNPs is proposed. The novel nanononwoven retains the enhanced antimicrobial activities from nanofeatured AgNPs without detectable AgNPs leaching, which holds great potential for safe and recyclable use.     

Synthesis and characterization of dextran-capped silver nanoparticles with enhanced antibacterial activity

Dextran-capped silver nanoparticles were synthesized by reducing silver nitrate with NaBH4 in the presence of dextran as capping agent. The characters of silver nanoparticles were investigated using UV-Vis spectrophotometer, nano-grainsize analyzer, X-ray diffraction, and transmission electron microscopy. Results showed that the silver nanoparticles capped with dextran were in uniform shape and narrow size distribution. Moreover, compared with polyvinylpyrrolidone (PVP)-capped silver nanoparticles, the dextran-capped ones possessed better stability. Antibacterial tests of these silver nanoparticles were carried out for Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Results suggested that the dextran-capped silver nanoparticles had high antibacterial activity against both Gram-positive and Gram-negative bacteria. In addition, the cytotoxicity in vitro of the dextran-capped silver nanoparticles was investigated using mouse fibrosarcoma cells (L929). The toxicity was evaluated by the changes of cell morphology and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. Results indicated that these silver nanoparticles had slight effect on the survival and proliferation of L-929 cells at their minimal inhibitory concentration (MIC). After modified by dextran, the physiochemical properties of the silver nanoparticles had been improved. We anticipated that these dextran-capped silver nanoparticles could be integrated into systems for biological and pharmaceutical applications.     

纳米银/聚乙烯醇复合物的生物合成及其对6种水产病原菌的抑菌活性

纳米银作为一种新型抑菌剂有望成为传统抑菌剂的替代品,制备稳定、高效、环保的新型纳米银抑菌产品成为当今的研究热点。本研究以葡萄籽提取液为还原剂和稳定剂,聚乙烯醇(PVA)为载体,采用一步法“绿色”生物合成出一种纳米银/聚乙烯醇复合物(AgNPs/PVA)。通过紫外-可见(UV-Vis)吸收光谱、透射电镜(TEM)、X射线衍射(XRD)等手段对合成产物进行了表征。结果表明银离子被葡萄籽提取物成功还原成纳米银并附着在PVA的表面,纳米银颗粒均匀,呈现单分散状态,粒径较小,平均粒径为14 nm左右。AgNPs/PVA对鳗弧菌、溶藻弧菌、副溶血弧菌、哈维氏弧菌、灿烂弧菌及点状气单胞菌等6种典型的水产病原菌均有显著的抑菌效果。以溶藻弧菌为指示菌,AgNPs/PVA的最小抑菌浓度(MIC)为1.1 μg/mL,最小杀菌浓度(MBC)为2.2 μg/mL。AgNPs/PVA的Zeta电位为?24.1 mV,表明纳米银颗粒间有很强的排斥力,为其稳定分散提供保障,后续实验证明制备的AgNPs/PVA具有良好的稳定性和热稳定性。以上研究结果表明,AgNPs/PVA复合材料在水产养殖病害防治中具有广阔的应用前景。      

Porcine skin gelatin–silver nanocomposites: synthesis,characterisation, cell cytotoxicity,and antibacterial properties

Silver nanoparticles (AgNPs) were synthesised with hydrothermal autoclaving technique by using AgNO₃ salt (silver precursor) at different concentrations (0.01, 0.1, 0.55, 1.1, 5.5, and 11 mM) and porcine skin (1% (w/v)) gelatin polymeric matrix (reducing and stabiliser agent). The reaction was performed in an autoclave at 103 kPa and 121°C and the hydrothermal autoclaving exposure time and AgNO₃ molar concentration were varied at a constant porcine skin gelatin concentration. The as‐prepared AgNPs were characterised by UV–visible spectroscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. The antibacterial properties of AgNPs were tested against gram‐positive and gram‐negative bacteria. Furthermore, 3‐(4,5‐dimethylthiazol‐2‐yl) 2,5‐diphenyltetrazolium bromide and 2,2‐diphenyl‐1‐picrylhydrazyl assays were used to test whether the synthesised AgNPs can be potentially applied in cancer therapy or used as an antioxidant. This approach is a promising simple route for synthesising AgNPs with a smaller average particle 10 nm diameter. Furthermore, AgNPs exhibited a good cytotoxicity activity, reducing the viability of the liver cancer cell line HepG2 with a moderate IC₅₀; they also showed a low‐to‐fair antioxidant activity. In addition, AgNPs had a remarkable preferential antibacterial activity against gram‐positive bacteria than gram‐negative bacteria. Therefore, these fabricated AgNPs can be used as an antibacterial agent in curative and preventive health care.Inspec keywords: gelatin, silver, nanoparticles, nanocomposites, nanobiotechnology, biomedical materials, antibacterial activity, microorganisms, Fourier transform infrared spectra, ultraviolet spectra, visible spectra, transmission electron microscopy, cancer, cellular biophysicsOther keywords: porcine skin gelatin–silver nanocomposites, cell cytotoxicity, antibacterial properties, silver nanoparticles, hydrothermal autoclaving technique, gelatin polymeric matrix, UV–visible spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, gram‐positive bacteria, gram‐negative bacteria, 3‐(4,5‐dimethylthiazol‐2‐yl) 2,5‐diphenyltetrazolium bromide assays, 2,2‐diphenyl‐1‐picrylhydrazyl assays, cancer therapy, antioxidant, liver cancer cell line HepG2, Ag     

Characterization of phyto-nanoparticles from Ficus krishnae for their antibacterial and anticancer activities

Background: Ovarian cancer is deadliest of fifth leading cause of death in women worldwide. This is due to advanced-stage disease rate associated with the development of chemoresistance. Hence, the current study emphasizes the process of synthesis of silver nanoparticles (AgNPs) from green chemistry method. Ficus krishnae is a perennial plant, native to India, used in folklore medicine to treat various diseases.

Objective: For the development of reliable, ecofriendly, less expensive process for the synthesis of AgNPs against bacterial and ovarian cancer.

Methodology: The synthesis of silver nanoparticles from stem bark of Ficus krishnae was carried out. The synthesized nanoparticles are subjected by UV-Vis spectrophotometer, scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and FTIR analysis. The antibacterial efficacy also determined by disc diffusion method, MIC, CFU and growth curve. In vitro cytotoxicity effect of aqueous extract and AgFK nanoparticle in ovarian cancer cell line by MTT assay was performed.

Results: The formation of AgNPs was confirmed by UV-VIS spectroscopic absorbance shown that peak at 435?nm. XRD photograph has indicated the face-centered cubic structure of the synthesized AgNPs. SEM study demonstrated that the size from 160 to 260?nm with interparticle distance, whereas shape is spherical. The particle size were ranging from 15 to 28?nm determined by XRD pattern. The antibacterial and cytotoxicity activity of this nanoparticle has showed a potential activity when compared with standards.

Conclusion: The present study confirms that the biosynthesized AgNPs from Ficus krishnae stem bark extract have a great affiance as antibacterial and anticancer agent.     

The influence of the surface chemistry of silver nanoparticles on cell death

The influence of the surface chemistry of silver nanoparticles (AgNPs) on p53 mediated cell death was evaluated using human dermal fibroblast (HDF) and lung cancer (A549) cells. The citrate reduced AgNPs (C-AgNPs) were modified with either lactose (L-AgNPs) or a 12-base long oligonucleotide (O-AgNPs). Both unmodified and modified AgNPs showed increased concentration and time dependent cytotoxicity and genotoxicity causing an increased p53 up-regulation within 6 h and led to apoptotic or necrotic cell deaths. The C-AgNPs induced more cytotoxicity and cellular DNA damage than the surface modified AgNPs. Modifying the C-AgNPs with lactose or the oligonucleotide reduced both necrotic and apoptotic cell deaths in the HDF cells. The C-AgNPs caused an insignificant necrosis in A549 cells whereas the modified AgNPs caused necrosis and apoptosis in both cell types. Compared to the O-AgNPs, the L-AgNPs triggered more cellular DNA damage, which led to up-regulation of p53 gene inducing apoptosis in A549 cells compared to HDF cells. This suggests that the different surface chemistries of the AgNPs cause different cellular responses that may be important not only for their use in medicine but also for reducing their toxicity.     

Green synthesis and evaluation of silver nanoparticles for antimicrobial and biochemical profiling in Kinnow (Citrus reticulata L.) to enhance fruit quality and productivity under biotic stress

Green synthesis of silver nanoparticles (AgNPs) by utilising plant extract is an emerging class of nanotechnology. It revolutionizes all the field of biological sciences by synthesizing chemical free AgNPs. In the present study, AgNPs were synthesised by utilising Moringa oleifera leaves as the main reducing and stabilising agent and characterised through UV–visible spectroscopy, zeta analyser, X‐ray diffraction spectroscopy (XRD), energy dispersive X‐ray (EDX), and scanning electron microscopy (SEM). The different concentrations of biosynthesised AgNPs (10, 20, 30, and 40 ppm) were exogenously applied on the already infected plants (canker) of Citrus reticulata at different day intervals. The AgNPs at a concentration of 30 ppm was found to be most suitable concentration for creating the resistance against canker disease in Citrus reticulata. The enzymatic activities were also explored and it was found that 30 ppm concentration of biosynthesised AgNPs significantly reduced the biotic stress. Fruit quality and productivity parameters were also assessed and it was found that fruit quality and productivity were significant in response to 30 ppm concentration of biosynthesised AgNPs. The present work highlights the potent role of biosynthesised AgNPs, which can be used as biological control of citrus diseases and ultimately improving the quality and productivity of Citrus.Inspec keywords: X‐ray diffraction, scanning electron microscopy, silver, X‐ray chemical analysis, biochemistry, ultraviolet spectra, atomic force microscopy, visible spectra, biotechnology, microorganisms, nanoparticles, antibacterial activity, enzymes, nanotechnology, electrokinetic effects, plant diseases, crops, product qualityOther keywords: green synthesis, silver nanoparticles, fruit quality, chemical‐free AgNP synthesis, antimicrobial activity, biochemical profiling, Citrus reticulata L, Kinnow productivity, nanotechnology, Moringa oleifera leaves, stabilising agent, UV–Visible spectroscopy, zeta analyser, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, scanning electron microscopy, atomic force microscopy, Xanthomonas axonopodis, canker disease, enzymatic activities, superoxide dismutase, peroxidase, catalase, biological control, Ag     

Effect of green synthesised silver nanoparticles on morphogenic and biochemical variations in callus cultures of kinnow mandarin (Citrus reticulata L.)

Citrus reticulata is economically important tree fruit crop in Pakistan, fortified with various nutrients and minerals including Vitamin C and secondary metabolites. Nanotechnology is a twenty‐first century science and deals with production of minute particles termed as nanoparticles. In present study, silver nanoparticles (AgNPs) were synthesised through green method by utilising leaves of Olea europea as main reducing and capping agent. The synthesised AgNPs were characterised through UV visible spectroscopy, SEM, and energy dispersive X‐ray. Furthermore, different concentrations of AgNPs (10, 20, 30 ppm) in combination with Thidiazuron (0.5, 1.0 mg/l) were added onto MS medium to study development and secondary metabolites production in callus culture of C. reticulata. Callus induction percentage (96%) was more in 20 ppm AgNPs and 1 mg/l TDZ concentration. Moreover, high total phenolic, flavonoid contents, and antioxidant activity was observed in 20 ppm AgNPs combined with 0.5 and 1 mg/l TDZ. Enzymatic components (SOD, POD and CAT) were increased in MS medium augmented with 30 ppm AgNPs and TDZ. The total protein content (TPC) was significant in callus cultures treated with TDZ only. This study provides the first evidence of green synthesised AgNPs on callus culture developments and further quantification of biochemical profiling in C. reticula. Inspec keywords: nanoparticles, silver, ultraviolet spectra, scanning electron microscopy, antibacterial activity, agricultural products, nanotechnology, biotechnology, agricultural engineering, nanofabrication, genetic engineering, cropsOther keywords: green synthesised silver nanoparticles, morphogenic variations, biochemical variations, kinnow mandarin, citrus reticulata L, nutrients, minerals, green method, UV visible spectroscopy, energy dispersive X‐ray, MS medium, secondary metabolites production, callus induction percentage, TDZ, flavonoid contents, callus culture developments, capping agent, phenolic contents, tree fruit crop     

One‐pot green synthesis and structural characterisation of silver nanoparticles using aqueous leaves extract of Carissa carandas : antioxidant,anticancer and antibacterial activities

Facile green synthesis of silver nanoparticles (AgNPs) using an aqueous extract of Carissa carandas (C. carandas) leaves was studied. Fabrication of AgNPs was confirmed by the UV–visible spectroscopy which gives absorption maxima at 420 nm. C. carandas leaves are the rich source of the bioactive molecules, acts as a reducing and stabilising agent in AgNPs, confirmed by Fourier transforms infrared spectroscopy. The field emission scanning electron microscope revealed the spherical shape of biosynthesised AgNPs. A distinctive peak of silver at 3 keV was determined by energy dispersive X‐ray spectroscopy. X‐ray diffraction showed the facecentred cubic structure of biosynthesised AgNPs and thermal stability was confirmed by the thermogravimetric analysis. Total flavonoid and total phenolic contents were evaluated in biosynthesised AgNPs. Biosynthesised AgNPs showed free radical scavenging activities against 2, 2‐diphenyl‐1‐picrylhydrazyl test and ferric reducing antioxidant power assay. In vitro cytotoxicity against hepatic cell lines (HUH‐7) and renal cell lines (HEK‐293) were also assessed. Finally, biosynthesised AgNPs were scrutinised for their antibacterial activity against methicillin‐resistant Staphylococcus aureus, Shigella sonnei, Shigella boydii and Salmonella typhimurium. This study demonstrated the biofabrication of AgNPs by using C. carandas leaves extract and a potential in vitro biological application as antioxidant, anticancer and antibacterial agents.Inspec keywords: antibacterial activity, biomedical materials, cancer, tumours, nanomedicine, silver, nanoparticles, reduction (chemical), nanofabrication, ultraviolet spectra, visible spectra, field emission scanning electron microscopy, Fourier transform infrared spectra, X‐ray chemical analysis, X‐ray diffraction, thermal stability, thermal analysis, free radical reactions, toxicology, cellular biophysics, microorganismsOther keywords: total phenolic contents, free radical scavenging activities, 2,2‐diphenyl‐1‐picrylhydrazyl test, ferric reducing antioxidant power assay, in vitro cytotoxicity, hepatic cell lines HUH‐7, renal cell lines HEK‐293, antibacterial activity, methicillin‐resistant Staphylococcus aureus, Shigella sonnei, Shigella boydii, Salmonella typhimurium, biofabrication, in vitro biological application, Ag, total flavonoid contents, thermogravimetric analysis, thermal stability, face‐centred cubic structure, X‐ray diffraction, energy dispersive X‐ray spectroscopy, distinctive peak, spherical shape, field emission scanning electron microscope, Fourier transforms infrared spectroscopy, stabilising agent, reducing agent, bioactive molecules, absorption maxima, UV‐visible spectroscopy, plant extract colour, antibacterial activities, anticancer activities, antioxidant activities, Carissa carandas, aqueous leaves extract, silver nanoparticles, structural characterisation, one‐pot green synthesis