Use Of AgNPs Research Articles

Abstract 1745: Exploiting vulnerabilities to nanoparticle induced lipid peroxidation and proteotoxicity to treat drug resistant lung cancer

Abstract Protein quality control plays an essential role in cell survival. Clinically translated strategies to target protein quality control in cancer show some efficacy, but off-target effects are severe. We are investigating a new approach using nanomaterials to induce lipid peroxidation to trigger a cascade of protein oxidation, protein misfolding, and decreased protein degradative capacity in cancer cells without affecting normal cells. Our studies show that silver nanoparticles (AgNPs) cause dramatic increases in lipid peroxidation, 4-hydroxynonenal adducts (4-HNE), protein oxidation, protein aggregation, and proteotoxic stress signaling in a mesenchymal-like subset of non-small cell lung (NSCLC) and other cancers at doses that do not affect normal cells in vitro or vivo. Notably, AgNP sensitive NSCLCs are inherently resistant to clinically relevant therapies including epidermal growth factor receptor tyrosine kinase inhibitors ((EGFR-TKIs) e.g. erlotinib, gefitinib, olfatinib) and cisplatin. We identified two defining characteristics causing some cancers to be sensitive to AgNPs. The first is enrichment of cell membranes in polyunsaturated fatty acids (PUFAs), especially arachidonic (AA) and adrenic acid (AdA), which are prone to oxidation. The second is high-level synthesis and secretion of extracellular matrix (ECM), especially fibronectin and collagen, which places AgNP sensitive cancers under substantial baseline endoplasmic reticulum stress, making them susceptible to agents that increase proteotoxicity. Mechanistically, we find that in PUFA-enriched cancers, signaling from ECM sustains the AgNP sensitive phenotype by stimulating Akt activity and stabilizing cytoplasmic β-catenin. Transcriptionally active β-catenin increases expression of fibronectin and collagen, resulting in a positive feedback loop locking cells into the AgNP sensitive phenotype. Use of AgNPs to targeting vulnerabilities associated with ECM synthesis and signaling downstream of β-catenin is a novel approach to overcoming multiple EGFR-TKI resistance mechanisms. Ultimately, our goal is to elucidate the precise mechanism by which AgNPs overcome resistance to clinically available EGFR-TKIs. Identification of the specific drivers of sensitivity to AgNPs (and potentially other metal nanoparticles) will guide development of therapeutic metal nanoparticles, enable selection of cancer patients who will benefit most or are at greatest risk to nanomaterial exposure, and will spur innovation of other treatments that exploit the vulnerabilities we identify. Citation Format: Christina Snyder, Monica Rohde, Ravi N. Singh. Exploiting vulnerabilities to nanoparticle induced lipid peroxidation and proteotoxicity to treat drug resistant lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1745.

Abstract 373: Silver nanoparticles are selectively cytotoxic to neurofibromin 1 deficient peripheral nerve sheath tumors

Abstract Neurofibromatosis type 1 (NF1) is the most common neurogenic disorder affecting 1 in every 3,000 people worldwide. NF1 is defined by heterozygous loss-of-function of the neurofibromin 1 gene (NF1). NF1 patients develop neurofibromas with near complete penetrance. These neurofibromas include peripheral nerve sheath tumors (PNSTs) such as plexiform neurofibromas (pNFs) and malignant PNSTs (MPNSTs). Current standard of care shows incomplete penetrance limiting clinical utility. Therefore, treatments to selectively and safely remove PNST cells would be advantageous. Biallelic loss of functional NF1 is the major driving force in the development of PNSTs. NF1 is a tumor suppressor gene responsible for suppressing Ras activity. Loss of NF1 increases Ras activity and subsequently increases intracellular reactive oxygen species (ROS). We and other groups have demonstrated that systemically administrable silver nanoparticles (AgNPs) are cytotoxic to a variety of cancers. We further showed that AgNP-mediated cytotoxicity is dependent upon intracellular ROS which induces rapid ionization (activation) of Ag0 to cytotoxic Ag+. Therefore, AgNPs represent a rational cancer-selective therapy for NF1-deficient PNSTs as these cells are enriched for ROS relative to non-cancerous cells. In this study, we found that AgNPs are significantly (~5-fold) more cytotoxic to NF1-null MPNST cells relative to tumor cell of origin Schwann cells and ~7-fold more cytotoxic to pNF cells relative to patient matched Schwann cells. Sporadic NF1 wild-type MPNST cells were not sensitive to AgNP. We further explored the relationship between oxidative stress and AgNP-mediated cytotoxicity in PNSTs. We found that co-administration of oxidative stress inducing cumene hydroperoxide with AgNP augments the cytotoxicity of AgNP in otherwise AgNP-tolerant cells (Schwann cells, NF1-wildtype MPNSTs). Importantly, either agent alone only showed modest cytotoxicity. As NF1 gene expression levels correlated with AgNP-sensitivity, we further studied this possible interaction by reintroducing NF1 into NF1-null MPNST. Remarkably, NF1 restoration decreased sensitivity to AgNP. This change is unique to AgNP as there was no altered sensitivity to standard of care chemotherapy doxorubicin. Conversely, knockdown of NF1 expression in Schwann cells increased sensitivity to AgNP with no corresponding change in sensitivity to pNF standard of care MEK inhibitor selumetinib. In conclusion, our work provides evidence that a therapeutic window exists for the safe use of AgNPs as a precision medicine to treat NF1-null PNSTs. Citation Format: Garrett Alewine, Adithya Ghantae, Christina Mamrega, Jerrica L. Knight, Bashnona Attiah, Robert A. Coover, Cale D. Fahrenholtz. Silver nanoparticles are selectively cytotoxic to neurofibromin 1 deficient peripheral nerve sheath tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 373.

Silver Nanoparticles Targeting the Drug Resistance Problem of Streptococcus dysgalactiae: Susceptibility to Antibiotics and Efflux Effect.

The present work is a continuation of our translational research focusing on the use of silver nanoparticles (AgNPs) to solve the global problem of antibiotic resistance. In vivo fieldwork was done with 300 breeding farm cows with serous mastitis. Ex vivo assays revealed that after cow treatment with the antibiotic drug Spectromast LCTM, S. dysgalactiae susceptibility to 31 antibiotics dropped by 22.9%, but after treatment with Argovit–CTM AgNPs, it was raised by 13.1%. This was explained by the fact that the percentage of isolates with an efflux effect after Spectromast LC treatment resulted in an 8% increase, while Argovit-C-treatment caused a 19% decrease. The similarity of these results to our previous results on S. aureus isolates from mastitis cows treated with the antibiotic drug Lactobay and Argovit–CTM AgNPs was shown. So, mastitis treatments with Argovit-CTM AgNPs can partially return the activity of antibiotics towards S. dysgalactiae and S. aureus, while, in contrast, treatments with antibiotic drugs such as Spectromast LC and Lactobay enhance bacterial resistance to antibiotics. The results of this work strengthen the hope that in the future the use of AgNPs as efflux pump inhibitors will recover the activity of antibiotics, and thus will preserve the wide spectrum of antibiotics on the market.

1,4-bis[β-(2-benzoxazoly1) vinyl] benzene (BBVB) laser dye and sodium salt of meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS); spectroscopic investigation and DFT, NBO and TD-DFT calculations

Excitation energy transfer (ET) from 1,4-bis[β-(2-benzoxazoly1) vinyl] benzene as a donor to sodium salt of meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS) as an acceptor was investigated in the absence and presence of metallic silver nanoparticles (Ag NPs). The emission intensities and Stern –Volmer constants (KSV) of the ET processes were calculated in methanol (MeOH) and 40% ethylene glycol (EG) as 5.87 × 104 M−1 and 6.27 × 104 M−1, respectively. KSV value in the presence of Ag NPs was 1.028 × 105 M−1 in methanol, much higher than in absence of NPs. This is attributed to the role of Ag NPs in increasing the strength of the donor–acceptor interactions. These results denote the use of Ag NPs for measuring the proximity of large biomolecules and ET-based assays. Also, the critical ET distance Ro was calculated as 36 Å. This magnitude is higher than the common value of 10 Å for the collisional ET mechanism. This high Ro value indicates the underlying mechanism as long-range dipole–dipole interaction. The BBVB, TPPS, and BBVB/TPPS molecular structures (MSs) were optimized using the DFT/ B3LYP/6-311G (d) method for the quantum calculations. The calculated electronic UV–Vis absorption spectra for BBVB and BBVB/TPPS MSs in MeOH were examined by the time-dependent density functional theory (TD-DFT) at CAM-B3LYP/6-311G++(3d,3p) level. Interestingly, all theoretical results of BBVB and BBVB/TPPS molecules were highly matched with the experimental results. Furthermore, the Natural Bond Orbital (NBO) analyses for BBVB and BBVB/TPPS MSs were obtained using the B3LYP/6-311G(d) level of theory.

Silver nanoparticles induce mitochondria-dependent apoptosis and late non-canonical autophagy in HT-29 colon cancer cells

Abstract The interactions of nanomaterials with biological materials such as immortalized cell lines are recently on the rise. Owing to this superiority, the biosynthesis of AgNPs using gallic acid as a reductant was implemented in this study. After being synthesized, the AgNPs were characterized using techniques such as dynamic light scattering, transmission electron microscopy, selected area electron diffraction, and X-ray diffraction methods. Furthermore, the AgNPs were assessed for their cytotoxic effects on the colorectal adenocarcinoma cell line HT-29. The mechanisms of such cell-killing effect were investigated by analyzing the expressions of 14 mRNAs using quantitative polymerase chain reaction. The outcomes indicate that the synthesized AgNPs were cytotoxic on HT-29 cells. The expressions of all apoptotic genes analyzed including cyt-C, p53, Bax, Bcl2, CASP3, CASP8, CASP9, and CASP12 were upregulated. With regard to the autophagy-related genes, Beclin-1, XBP-1, CHOP, and LC3-II were upregulated, whereas the expressions of ATG3 and ATG12 were downregulated. To conclude, the AgNPs induced mitochondria-dependent apoptosis and non-canonical autophagy in HT-29 cells. A crosstalk did occur between autophagy and apoptosis in such a cell-killing effect. Hence, further studies are required to elucidate the exact mechanisms in animal models for further use of AgNPs in clinical medicine for the treatment of neoplasms of the digestive tract.

Size Characterization of Graphene‐coated Silver Nanoparticles for Drug Delivery System Design

Nanoparticles prove to be a promising tool for drug delivery due to their modifiable properties, such as size, which may offer more targeted delivery. Silver nanoparticles (AgNPs) have been shown to exert anticancer effects such as antiangiogenesis. Size control is crucial for the use of AgNPs as drug delivery systems because smaller AgNPs amplify cytotoxicity in both cancerous and healthy cells. Another way that AgNPs are cytotoxic is through the release of silver (Ag+) ions. It has been shown that AgNPs below 10 nm in size have a comparable toxicity to Ag+ ions. In this study, AgNPs were coated with graphene quantum dots. Graphene quantum dots (GQDs) are nanosheets of carbon. These nanosheets of carbon may control the release of silver ions and provide additional benefits such as increased surface area for drug loading and increased drug solubility. The objective of this study is to synthesize graphene quantum dot‐coated silver nanoparticles (AgGQDs) to serve as drug delivery systems. We hypothesize that our methods will produce AgGQDs larger than 10 nm to avoid excessive cytotoxicity. The GQDs were synthesized by pyrolysis of citric acid and used as reducing agents for the synthesis of AgGQDs. The GQDs were characterized using X‐ray Photoelectron Spectroscopy (XPS). The AgGQDs were characterized via Transmission Electron Microscopy (TEM) and in situ Energy‐dispersive X‐ray Spectroscopy (EDS). EDS confirmed that the images observed were silver nanoparticles. TEM images showed that the AgGQDs were spherical and had a size of approximately 20‐25 nm in diameter. Based on these results, we can conclude that our AgGQDs will not be drastically cytotoxic due to their intermediate size.

ADVANTAGES OF NOVEL DRUG DELIVERY SYSTEM AND SILVER NANOPARTICLES FOR HERBAL DRUGS; AND MEDICINAL IMPORTANCE OF Crotalaria burhia PLANT: A REVIEW

Herbal or natural medicines have been used since ancient time due to easy availability and less side effects. Still 80% population of developing countries uses herbal medicines to treat common diseases. The Crotalaria burhia plant is shrub having several chemical constituents like flavonoids, hormones, alkaloids phenolic compounds and terpenes etc. It traditionally used for fever, inflammation, chronic kidney pain, cancer, general bacterial infections, fungal infections, gout, cough, arthritis, diarrhea, abdominal pain, nausea, and typhoid etc. It has also been used in cattle for the removal of placenta after delivery. Due to traditional dosage formulation a few amount of drug reach to its target tissue. In recent past, Phyto-pharmaceutical work leads to new medicine delivery methods for example nanoparticles, microparticles, nano-suspension and liposome’s etc. For herbal medicine, this unique medication delivery mechanism enhances stability, solubility, absorption, bioavailability and therapeutic effect. The carrier in nano dosage forms increases the drug concentration at targeted tissue due to which systemic side effects can be reduced. Silver nanoparticles have been emerged as a potent component of novel drug delivery system because silver nanoparticles (Ag NPs) have its own antimicrobial and anticancer activities but they are non-toxic to human body. Ag NPs synthesized by natural plant extracts have shown enhanced anticancer and antimicrobial activities. The silver nanoparticles exert its antimicrobial and anticancer activity by disrupting cell wall permeability and cellular respiration. Recently use of Ag NPs has been increased to overcome the antibiotics resistance. Silver nanoparticles have ability to sterilize the hospital items. This new method of drug delivery is a protective way for administration of herbal drugs to target tissues. 

Changes in primary metabolites and volatile organic compounds in cotton seedling leaves exposed to silver ions and silver nanoparticles revealed by metabolomic analysis.

In the area of climate change, nanotechnology provides handy tools for improving crop production and assuring sustainability in global agricultural system. Due to excellent physiological and biochemical properties, silver nanoparticles (AgNPs) have been widely studied for potential use in agriculture. However, there are concerns about the mechanism of the toxic effects of the accumulation of AgNPs on crop growth and development. In this study, the impacts of AgNPs on cotton (Gossypium hirsutum) seedlings were evaluated by integrating physiological and comprehensive metabolomic analyses. Potting-soil-grown, two-week-old cotton seedlings were foliar-exposed to 5 mg/plant AgNP or 0.02 mg/plant Ag+ (equivalent to the free Ag+ released from AgNPs). Primary metabolites and volatile organic compounds (VOCs) were identified by gas chromatography–mass spectrometry (GC-MS) and solid-phase microextraction (SPME) GC-MS, respectively. AgNPs inhibited the photosynthetic capacity of the cotton leaves. The metabolic spectrum analysis identified and quantified 73 primary metabolites and 45 VOCs in cotton leaves. Both treatments significantly changed the metabolite profiles of plant leaves. Among the primary metabolites, AgNPs induced marked changes in amino acids, sugars and sugar alcohols. Among the VOCs, 13 volatiles, mainly aldehydes, alkanes and terpenoids, were specifically altered only in response to AgNPs. In summary, our study showed that the comprehensive influence of AgNPs on primary metabolites and VOCs was not merely attributed to the released Ag+ but was caused by AgNP-specific effects on cotton leaves. These results provide important knowledge about the physiological and chemical changes in cotton leaves upon exposure to AgNPs and offer a new insight for supporting the sustainable use of AgNPs in agriculture.

Pro-inflammatory effects of silver nanoparticles in the intestine.

Nanotechnology is a promising technology of the twenty-first century, being a rapidly evolving field of research and industrial innovation widely applied in our everyday life. Silver nanoparticles (AgNP) are considered the most commercialized nanosystems worldwide, being applied in diverse sectors, from medicine to the food industry. Considering their unique physical, chemical and biological properties, AgNP have gained access into our daily life, with an exponential use in food industry, leading to an increased inevitable human oral exposure. With the growing use of AgNP, several concerns have been raised, in recent years, about their potential hazards to human health, more precisely their pro-inflammatory effects within the gastrointestinal system. Therefore a review of the literature has been undertaken to understand the pro-inflammatory potential of AgNP, after human oral exposure, in the intestine. Despite the paucity of information reported in the literature about this issue, existing studies indicate that AgNP exert a pro-inflammatory action, through generation of oxidative stress, accompanied by mitochondrial dysfunction, interference with transcription factors and production of cytokines. However, further studies are needed to elucidate the mechanistic pathways and molecular targets involved in the intestinal pro-inflammatory effects of AgNP.

Photochemical effect of silver nanoparticles on flesh fly larval biological system

With the progress of nanoscience and its applications, silver nanoparticles (AgNPs) have become one of the most interesting nanoparticles owing to their use in different fields. However, the excessive use of AgNPs and its products may cause toxicity in both the environment and in human health. The main goal of this research is to study the toxic and photochemical effects of AgNPs against Sarcophaga argyrostoma larvae through ultrastructure, morphological change, and DNA damage. Treating midgut epithelium with AgNPs led to many alterations in dark conditions, disintegrated epithelium, swollen cells, and shrunken nucleus. Organelles appeared in a loose manner and mitochondria were without cristae, endoplasmic reticulum had dark spots, and peritrophic membrane was loose in appearance. Fatty tissues were vacuolized and muscle fibers lacked normal striations and had many gaps and lysosomal bodies. In the light conditions, the epithelium appeared with detached cells and many vacuoles, organelles were ruptured with many gaps in between, and secretory vesicles were scattered. Peritrophic membrane disappeared. Muscles collapsed and vacuolized loosed fatty tissues were detected. On the other hand, control larvae epithelium appeared regularly distinct, with organelles intact and muscles had clear normal striations. Data showed that AgNPs caused ultrastructural and morphological changes of the external cuticle of the 4th instar larvae along with a significant effect on DNA damage that occurred after the larval treatment, reflecting the toxicity of AgNPs.

GREEN SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES USING HELIOTROPIUM INDICUM L. LEAVES EXTRACT AND ANTIMICROBIAL ACTIVITY

Silver is known for its antimicrobial effects and silver nanoparticles have become a promising synthetic strategy due to its antimicrobial potential. The study was carried out in Heliotropium indicum L. aqueous leaves extract for determining the antimicrobial activity of silver nanoparticles (AgNPs) against human skin pathogens with statistical tests at 1% level of significance. Characterization of AgNPs was carried out by UV-Vis Spectroscopy, X-ray Diffraction Spectroscopy (XRD) and Scanning Electron Microscopy (SEM). Antimicrobial activities of AgNPs was determined by agar well diffusion method and MIC was determined by resazurin-based turbidometric method. The UV spectroscopic analysis showed the highest absorbance peak at 420 nm. The particle size and structure was confirmed by SEM analysis and it was revealed that the formed particles were of different shapes but predominantly spherical with an average size of 77-98 nm with interparticle distance. The crystalline nature of the AgNPs was determined by X-ray diffraction patterns. The biosynthesized AgNPs exhibited excellent antibacterial activity against Pseudomonas aeruginosa (MTCC 4676) and antifungal activity against Candida albicans (MTCC 183). Kolmogorov-Smirnov and Shapiro-Wilks test, Levene’s test of homogeneity of variance and ANOVA were performed using SPSS software. The ANOVA test revealed that the zone of inhibition against P. aeruginosa, S. aureus, B. cereus, T. rubrum and C. albicans was significantly different among samples at 1% level of significance (p less than 0.01). The potent antimicrobial activity may justify the biomedical use of AgNPs as antimicrobial agents for controlling microbial infections.

Exploring the Bioactive Potentials of C60-AgNPs Nano-Composites against Malignancies and Microbial Infections.

At present, the potential role of the AgNPs/endo-fullerene molecule metal nano-composite has been evaluated over the biosystems in-vitro. The intra-atomic configuration of the fullerene molecule (C60) has been studied in-vitro for the anti-proliferative activity of human breast adenocarcinoma (MDA-MB-231) cell lines and antimicrobial activity against a few human pathogens that have been augmented with the pristine surface plasmonic electrons and antibiotic activity of AgNPs. Furthermore, FTIR revealed the basic vibrational signatures at ~3300 cm−1, 1023 cm−1, 1400 cm−1 for O-H, C-O, and C-H groups, respectively, for the carbon and oxygen atoms of the C60 molecule. NMR studies exhibited the different footprints and magnetic moments at ~7.285 ppm, explaining the unique underlying electrochemical attributes of the fullerene molecule. Such unique electronic and physico-chemical properties of the caged carbon structure raise hope for applications into the drug delivery domain. The in-vitro dose-dependent application of C60 elicits a toxic response against both the breast adenocarcinoma cell lines and pathogenic microbes. That enables the use of AgNPs decorated C60 endo fullerene molecules to design an effective anti-cancerous drug delivery and antimicrobial agent in the future, bringing a revolutionary change in the perspective of a treatment regime.

Functionalized silver nanoparticles for SERS amplification with enhanced reproducibility and for ultrasensitive optical fiber sensing in environmental and biochemical assays.

Plasmonic sensors have broad application potential in many fields and are promising to replace most bulky sensors in the future. There are various method-based chemical reduction processes for silver nanoparticle production with flexible structural shapes due to their simplicity and rapidity in nanoparticle fabrication. In this study, self-assembled silver nanoparticles (Ag NPs) with a plasmon peak at 424 nm were successfully coated onto -NH2-functionalized glass and optical fiber sensors. These coatings were rapidly produced via two denaturation reactions in plasma oxygen, respectively, and an APTES ((3-aminopropyl)triethoxysilane) solution was shown to have high strength and uniformity. With the use of Ag NPs for surface-enhanced Raman scattering (SERS), excellent results and good stability with the detection limit up to 10-10 M for rhodamine B and 10-8 M for methylene blue, and a signal degradation of only ∼20% after storing for 30 days were achieved. In addition, the optical fiber sensor with Ag NP coatings exhibited a higher sensitivity value of 250 times than without coatings to the glycerol solution. Therefore, significant enhancement of these ultrasensitive sensors demonstrates promising alternatives to cumbersome tests of dye chemicals and biomolecules without any complicated process.

Green synthesis of silver nanoparticles using green tea leaf extract, characterization and evaluation of antimicrobial activity.

The use of nanoparticles in medicine, nanomedicine, is very important to diagnose and treat diseases; among the various metallic nanoparticles, silver nanoparticles (AgNPs) are very popular due to their physical, chemical, and biological properties, encompassing a range of activities such as antiviral, antifungal, anti-inflammatory, and anticancer activities. In this study, the synthesis of AgNPs was conducted by the use of a nontoxic, ecofriendly method. Green tea (GT) leaf extract was used as a reducing agent to convert silver ions into free AgNPs. The UV-vis spectrum showed a peak at 410 nm, confirming the presence of AgNPs. A Fourier-transform infrared (FTIR) analysis of the GT extract and GT AgNPs display spectra that is identical to those of polyphenols, polysaccharides, and proteins. All the vibrational peaks in the GT extract spectrum were shifted in the AgNP spectrum, becoming narrower after the encapsulation of nanoparticles. The scanning electron microscopy (SEM) images confirm the presence of AgNPs with different sizes, ranging from 15 to 33 nm. Furthermore, the antibacterial activity of the synthesized AgNPs in three different concentrations (10, 20, and 50 mg ml−1) showed appreciable inhibition of bacterial growth against Staphylococcus aureus and Klebsiella sp. From the above findings, we can recommend the use of AgNPs from GT leaf extracts as an antimicrobial agent to treat chronic infections.

Improved transformation of Agrobacterium assisted by silver nanoparticles.

In transgenic plant development, the low transformation efficiency of Agrobacterium with exogenous DNA is the major constraint, and hence, methods to improve its transformation efficiency are needed. Recently, nanoparticlemediated gene transfer has evolved as a key transformational tool in genetic transformation. Since silver nanoparticles (AgNPs) can induce pores on the cell membrane, their efficacy in the improvement of conventional calcium chloride freeze-thaw technique of transformation of Agrobacterium was explored in this study. Agrobacterium cells in the exponential growth phase were exposed to different concentrations of AgNPs (0.01, 1, 5, 10, and 20 mg/l), and the half-maximal effective concentration (EC50) was determined via Probit analysis using the SPSS software. Transformation efficiency of AgNPs alone and in combination with calcium chloride was compared with that of the conventional calcium chloride freeze-thaw technique. AgNPs at a concentration of 0.01 mg/l in combination with calcium chloride (20 mM) showed a ten fold increase in the transformation efficiency (3.33 log CFU (colony-forming unit/microgram of DNA) of Agrobacterium tumefaciens strain EHA 105 with plasmid vector pART27 compared with the conventional technique (2.31 log CFU/μg of DNA). This study indicates that AgNPs of size 100 nm can eliminate the freeze-thaw stage in the conventional Agrobacterium transformation technique, with a 44% improvement in efficiency. The use of AgNPs (0.01 mg/l) along with 20 mM calcium chloride was found to be an economically viable method to improve the transformation of Agrobacterium with exogenous plasmid DNA.

Effects of different treatments of silver nanoparticles (AgNPs) on the growth & physiological characteristics of lotus (Nelumbo nucifera)

Lotus (Nelumbo nucifera Gaertn.) is an aquatic perennial plant with various values, such as ornamental flowers, vegetables, food, and herbal medicine. It is cultivated and consumed throughout the different regions in Vietnam as a symbol associated with local culture. This study was conducted to evaluate the effects of four other treatments of silver nanoparticles (AgNPs) on the growth of lotus in crop 2021. In the present study, we examined the effects of 4 treatments: control - no AgNPs (CT), treating the soil with AgNPs 4mg/L 5 days before planting (T1), treating plants with AgNPs 4mg/L before planting (T2), and a combination of soil treatment, plant treatment, and periodic foliar application at 4mg/L (T3). The results show that AgNPs application by different methods significantly increased plant height, leaf diameter, fresh leaf weight, dry leaf weight, and some biochemical aspects compared with the control. Furthermore, exposure to AgNPs elevated the activities of peroxidase (POD), superoxide dismutase (SOD). Among the different of AgNPs applications, plants treated with T3 showed the highest efficiency. In addition, the chlorophyll content and diameter of floating and upright leaves were positively correlated with dry leaf mass. Thus, the current use of AgNPs in agricultural sciences offers the prospect of researching their impact on various plants in the future.

Green Synthesis of Silver Nanoparticles Using Pomegranate and Orange Peel Extracts and Their Antifungal Activity against Alternaria solani, the Causal Agent of Early Blight Disease of Tomato.

This study aimed to synthesize silver nanoparticles (AgNPs) by pomegranate and orange peel extracts using a low concentration of AgNO3 solution to controlearly blight of tomato caused by Alternaria solani. The pathogen was isolated from infected tomato plants growing in different areas of Saudi Arabia. The isolates of this pathogen were morphologically and molecularly identified. Extracts from peels of pomegranate and orange fruits effectively developed a simple, quick, eco-friendly and economical method through a synthesis of AgNPs as antifungal agents against A. solani. Phenolic content in the pomegranate peel extract was greater than orange peel extract. Phenolic compounds showed a variation of both peel extracts as identified and quantified by High-Performance Liquid Chromatography. The phenolic composition displayed variability as the pomegranate peel extract exhibited an exorbitant amount of Quercitrin (23.62 mg/g DW), while orange peel extract recorded a high amount of Chlorogenic acid (5.92 mg/g DW). Biosynthesized AgNPs were characterized using UV- visible spectroscopy which recorded an average wavelength of 437 nm and 450 nm for pomegranate and orange peels, respectively. Fourier-transform infrared spectroscopy exhibited 32x73.24, 2223.71, 2047.29 and 1972.46 cm−1, and 3260.70, 1634.62, 1376.62 and 1243.76 cm−1 for pomegranate and orange peels, respectively. Transmission electron microscopy showed spherical shape of nanoparticles. Zetasizer analysis presented negative charge values; −16.9 and −19.5 mV with average particle sizes 8 and 14 nm fin case of pomegranate and orange peels, respectively. In vitro, antifungal assay was done to estimate the possibility of biosynthesized AgNPs and crude extracts of fruit peels to reduce the mycelial growth of A. solani. AgNPs displayed more fungal mycelial inhibition than crude extracts of two peels and AgNO3. We recommend the use of AgNPs synthesized from fruit peels for controlling fungal plant pathogens and may be applied broadly and safely in place by using the chemical fungicides, which display high toxicity for humans.

Antitumor Activities of Biosynthesized Silver Nanoparticles using Dodonaea viscosa (L.) Leaves Extract

Biosynthesis of silver nanoparticles (AgNPs) from plant extracts is considered one of the green chemistry methods, as this method is characterized by ease, fast and low cost to manipulate. Interestingly, AgNPs have an important role, especially in nano-medicine. Using AgNPs for cancer therapy are an affordable way to control tumor growth and constitute a choice strategy to fight cancer cells. First type of conventional cancer treatment is surgical treatment then radiation and chemotherapy. However, these treatments may work for some cancer subtypes, and have various side effects, in most cases, with high doses. In this study, silver nanoparticles (AgNPs) were biosynthesized using Dodonaea viscosa leaves extract. The formation of these particles was confirmed through the color change, UV-Visible Spectrophotometer displaying at 463nm.While the particles characterization was done by Surface Plasmon Resonance (SPR) band and Fourier Transform Infra-Red (FT-IR) spectroscopy which revealed the effective functional groups that have ability to bio-reduction silver ion Ag+. In addition, X-ray diffraction (XRD) determined the crystal structure of silver nanoparticles, as shown by the peaks at 2θ values of 38.1874, 46.2491, 57.5409 and76. 8313ο.The atomic force microscopy (AFM) analysis showed the size and the surface properties of biosynthesized nanoparticles, and the silver nanoparticles had an average size of 60.22 nm. Finally, scanning electron microscopy (SEM) showed spherical shape of AgNPs and having different average diameter D1 (21.10), D2 (21.39) and D3 (11.86) nm. In vitro, the synthesized AgNPs exhibited potential anti-tumor activities against human lung cancer (A549) and ovarian cancer (SK-OV-3) carcinoma cell lines in a dose-dependent manner with IC50 of 1.73 and 2.23µg.ml-1, respectively. Our results showed the promising use of AgNPs as an alternative treatment for cancer cells directly and selectively on A549 cell line at concentrations (2.000, 1.699, 1.398 and 1.301 μg /mL).

Colorimetric Detection and Adsorption of Mercury Using Silver Nanoparticles: A Bibliographic and Patent Review

Mercury (Hg) contamination is a problem that currently affects not only the environment but also human health. Various types of commercial adsorbents have been proposed for its removal. Silver is a noble element that can chemically adsorb mercury, forming amalgams. However, its use as an adsorbent presents the following disadvantages: rapid surface saturation and high cost. These limitations can easily be overcome using silver nanoparticles (AgNPs). With a size of less than 100 nm, their reactivity, their high surface area, and a minimal amount of metallic precursor, they are ideal candidates for mercury removal. This study presents a compendium of the use of conventional mercury adsorbents and the use of AgNPs for their colorimetric detection and removal in different matrices, in both the aqueous and gas phases of Hg0 and Hg2+ . In addition, the number of patents available in each case is analyzed. AgNPs as colorimetric sensors allow for quick detection of mercury in-situ. Additionally, the adsorption systems formed with AgNPs, allow for the obtaining of stable and chemically inert complexes, facilitating their recycling. It is concluded that the use of AgNPs is particularly efficient for the detection and removal of mercury, presenting a removal percentage of over 90%. As a result of the patents analyzed, its use is perfectly applicable at an industrial level.

Biosynthesis of silver nanoparticles using Cynara scolymus, Lavandula angustifolia, Alkanna Tinctoria and its antimicrobial activities—A comparative study

Nanotechnology is a promising field of science and involves use of nanoparticle with size ranging between 1 nm–100 nm. The phenomenal size properties enable nanoparticles to anchor a prominent place in various biomedical applications. Silver is known for its antimicrobial nature. This study elucidates the qualitative phytochemical properties of three plant extracts, its biogenic synthesis of silver nanoparticles and their antimicrobial activity. Green Silver nanoparticles (AgNPs) were synthesized from 1mM Silver Nitrate (AgNO3) solution using leaf extracts of Cynara scolymus (Artichoke), Alkanna tinctoria (Alkanet), and Lavandula angustifolia (Lavender) respectively. The synthesized silver nanoparticles were characterized visually, via UV–vis spectrophotometer and X-ray Diffraction (XRD). The biogenic particles were tested against pathogenic bacterial strains (Staphylococcus aureus, and Escherichia coli) and Plant pathogenic fungal strains (Aspergillus flavus and Aspergillus niger). The formation of AgNPs with size <100 nm was ensured by UV vis spectrophotometer and XRD. Antibacterial activity of lavender mediated AgNP was highly significant, followed by artichoke mediated AgNP and finally, alkanet AgNP were effective. However, in contrast, Artichoke mediated AgNP showed significant activity against plant fungal strains, followed by Alkanet AgNP, and finally by Lavender mediated AgNPs. We concluded that the three plants have versatile biochemical molecules responsible for broad spectrum of AgNP against bacterial and fungal strains. Studies on combined use of AgNPs with other antimicrobial agents may solve the problem of toxicity and possible risk of drug resistance.