Displaying publications 61 - 80 of 364 in total

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  1. Metal/metal oxide nanocomposites for bactericidal effect: A review
    Pachaiappan R, Rajendran S, Show PL, Manavalan K, Naushad M
    Chemosphere, 2021 Jun;272:128607.
    PMID: 33097236 DOI: 10.1016/j.chemosphere.2020.128607
    Many microbial species causing infectious disease all over the world became a social burden and creating threat among community. These microbes possess long lifetime, enhancing mortality and morbidity rate in affected organisms. In this condition, the treatment was ineffective and more chances of spreading of infection into other organisms. Hence, it is necessary to initiate infection control efforts and prevention activities against multidrug resistant microbes, to reduce the death rate of people. Seriously concerning towards this problem progress was shown in developing significant drugs with least side effects. Emergence of nanoparticles and its novelty showed effective role in targeting and destructing microbes well. Further, many research works have shown nanocomposites developed from nanoparticles coupled with other nanoparticles, polymers, carbon material acted as an exotic substance against microbes causing severe loss. However, metal and metal oxide nanocomposites have gained interest due to its small size and enhancing the surface contact with bacteria, producing damage to it. The bactericidal mechanism of metal and metal oxide nanocomposites involve in the production of reactive oxygen species which includes superoxide radical anions, hydrogen peroxide anions and hydrogen peroxide which interact with the cell wall of bacteria causing damage to the cell membrane in turn inhibiting the further growth of cell with leakage of internal cellular components, leading to death of bacteria. This review provides the detailed view on antibacterial activity of metal and metal oxide nanocomposite which possessed novelty due to its physiochemical changes.
    Matched MeSH terms: Silver
  2. Biodiesel synthesis from Prunus bokhariensis non-edible seed oil by using green silver oxide nanocatalyst
    Dawood S, Ahmad M, Zafar M, Asif S, Klemeš JJ, Bokhari A, et al.
    Chemosphere, 2022 Mar;291(Pt 2):132780.
    PMID: 34767846 DOI: 10.1016/j.chemosphere.2021.132780
    The present work investigates the proficiency of green silver oxide nanocatalyst synthesised from Monotheca buxifolia (Falc.) Dcne. leaves extract, and their application for biodiesel synthesis from novel Prunus bokhariensis seed oil (non-edible). The seed oil content of 55% and FFA content of 0.80 mg KOH/g were reported. Several analytical tools (EDX, FT-IR, SEM and XRD) were used to characterise the Ag2O nanocatalyst. Maximum (89%) FAME yield of the PBSOB (Prunus bokhariensis seed oil biodiesel) was achieved at ambient transesterification conditions i.e. 3.5 wt% nanocatalyst loading, 2.5 h reaction time, 130 °C of reaction temperature and 12:1 alcohol to oil ratio. The synthesised PBSOB was additionally characterised by analytical methods like, GC-MS and FT-IR. The different aspects of fuel were identified i.e. flash point (84 °C), kinematic viscosity (4.01 cSt @ 40 °C), sulphur content (0.0003 wt %), density (0.853 kg/L) and acid number (0.167 mg KOH/g). All the above properties were verified and agreed well with biodiesel international standards (European Union (14214), China GB/T (20828) and ASTM (6751, 951). In general, Prunus bokhariensis seed oil and Ag2O nanocatalyst seem to be remarkably active, cheap and stable candidates for the biodiesel industry in future.
    Matched MeSH terms: Silver Compounds
  3. Fulltext SARS-CoV-2 removal by mix matrix membrane: A novel application of artificial neural network based simulation in MATLAB for evaluating wastewater reuse risks
    Zahmatkesh S, Rezakhani Y, Chofreh AG, Karimian M, Wang C, Ghodrati I, et al.
    Chemosphere, 2023 Jan;310:136837.
    PMID: 36252897 DOI: 10.1016/j.chemosphere.2022.136837
    The COVID-19 outbreak led to the discovery of SARS-CoV-2 in sewage; thus, wastewater treatment plants (WWTPs) could have the virus in their effluent. However, whether SARS-CoV-2 is eradicated by sewage treatment is virtually unknown. Specifically, the objectives of this study include (i) determining whether a mixed matrixed membrane (MMM) is able to remove SARS-CoV-2 (polycarbonate (PC)-hydrous manganese oxide (HMO) and PC-silver nanoparticles (Ag-NP)), (ii) comparing filtration performance among different secondary treatment processes, and (iii) evaluating whether artificial neural networks (ANNs) can be employed as performance indicators to reduce SARS-CoV-2 in the treatment of sewage. At Shariati Hospital in Mashhad, Iran, secondary treatment effluent during the outbreak of COVID-19 was collected from a WWTP. There were two PC-Ag-NP and PC-HMO processes at the WWTP targeted. RT-qPCR was employed to detect the presence of SARS-CoV-2 in sewage fractions. For the purposes of determining SARS-CoV-2 prevalence rates in the treated effluent, 10 L of effluent specimens were collected in middle-risk and low-risk treatment MMMs. For PC-HMO, the log reduction value (LRV) for SARS-CoV-2 was 1.3-1 log10 for moderate risk and 0.96-1 log10 for low risk, whereas for PC-Ag-NP, the LRV was 0.99-1.3 log10 for moderate risk and 0.94-0.98 log10 for low risk. MMMs demonstrated the most robust absorption performance during the sampling period, with the least significant LRV recorded in PC-Ag-NP and PC-HMO at 0.94 log10 and 0.96 log10, respectively.
    Matched MeSH terms: Silver
  4. Exploring the potential of metal and metal oxide nanomaterials for sustainable water and wastewater treatment: A review of their antimicrobial properties
    Kamyab H, Chelliapan S, Hayder G, Yusuf M, Taheri MM, Rezania S, et al.
    Chemosphere, 2023 Sep;335:139103.
    PMID: 37271472 DOI: 10.1016/j.chemosphere.2023.139103
    Metallic nanoparticles (NPs) are of particular interest as antimicrobial agents in water and wastewater treatment due to their broad suppressive range against bacteria, viruses, and fungi commonly found in these environments. This review explores the potential of different types of metallic NPs, including zinc oxide, gold, copper oxide, and titanium oxide, for use as effective antimicrobial agents in water and wastewater treatment. This is due to the fact that metallic NPs possess a broad suppressive range against bacteria, viruses, as well as fungus. In addition to that, NPs are becoming an increasingly popular alternative to antibiotics for treating bacterial infections. Despite the fact that most research has been focused on silver NPs because of the antibacterial qualities that are known to be associated with them, curiosity about other metallic NPs as potential antimicrobial agents has been growing. Zinc oxide, gold, copper oxide, and titanium oxide NPs are included in this category since it has been demonstrated that these elements have antibacterial properties. Inducing oxidative stress, damage to the cellular membranes, and breakdowns throughout the protein and DNA chains are some of the ways that metallic NPs can have an influence on microbial cells. The purpose of this review was to engage in an in-depth conversation about the current state of the art regarding the utilization of the most important categories of metallic NPs that are used as antimicrobial agents. Several approaches for the synthesis of metal-based NPs were reviewed, including physical and chemical methods as well as "green synthesis" approaches, which are synthesis procedures that do not involve the employment of any chemical agents. Moreover, additional pharmacokinetics, physicochemical properties, and the toxicological hazard associated with the application of silver NPs as antimicrobial agents were discussed.
    Matched MeSH terms: Silver/chemistry
  5. Biochemical synthesis of silver nanoprticles using filamentous fungi Penicillium decumbens (MTCC-2494) and its efficacy against A-549 lung cancer cell line
    Majeed S, Abdullah MS, Dash GK, Ansari MT, Nanda A
    Chin J Nat Med, 2016 Aug;14(8):615-20.
    PMID: 27608951 DOI: 10.1016/S1875-5364(16)30072-3
    Biosynthesis of silver and other metallic nanoparticles is one of the emerging research area in the field of science and technology due to their potentiality, especially in the field of nano-biotechnology and biomedical sciences in order to develop nanomedicine. In our present study, Penicillium decumbens (MTCC-2494) was brought from Institute of Microbial Technology (IMTECH) Chandigarh and employed for extracellular biological synthesis of silver nanoparticles. Ag-NPs formation was appeared with a dark brown color inside the conical flask. Characterization of Ag-NPs were done by UV-Spectrophotometric analysis which showed absorption peak at 430 nm determines the presence of nanoparticles, Fourier transform infrared (FT-IR) spectroscopic analysis, showed amines and amides are the possible proteins involved in the stabilization of nanoparticles as capping agent. Atomic force Microscopy (AFM) confirmed the particle are spherical, size was around 30 to 60 nm and also the roughness of nanoparticles. Field emission scanning electron microscopy (FE-SEM) showed the topology of the nanoparticles and were spherical in shape. The biosynthesis process was found fast, ecofriendly and cost effective. Nano-silver particle was found to have a broad antimicrobial activity and also it showed good enhancement of antimicrobial activity of Carbenicillin, Piperacillin, Cefixime, Amoxicillin, Ofloxacin and Sparfloxacin in a synergistic mode. These Ag-NPs showed good anti-cancer activity at 80 μg·mL(-1)upon 24 hours of incubation and toxicity increases upon 48 hours of incubation against A-549 human lung cancer cell line and the synergistic formulation of the antibiotic with the synthesized nanoparticles was found more effective against the pathogenic bacteria studied.
    Matched MeSH terms: Silver/metabolism*; Silver/pharmacology*
  6. L-cysteine capped silver nanoparticles as chiral recognition sensor for ketoprofen enantiomers
    Obaid A, Mohd Jamil AK, Saharin SM, Mohamad S
    Chirality, 2021 11;33(11):810-823.
    PMID: 34486177 DOI: 10.1002/chir.23354
    A simple, inexpensive but effective approach for visual chiral recognition of ketoprofen enantiomers was developed using L-cysteine capped silver nanoparticles (L-Cys-AgNPs) as a colorimetric sensor. Upon the addition of R-ketoprofen to L-Cys-AgNPs, rapid aggregation occurred, and the solution changed color from yellow to green. However, the presence of S-ketoprofen did not induce any color change. The results were characterized using UV-Vis, FESEM, FT-IR, SERS, and zeta potential measurements. The chiral assay described in this work is easily distinguished with the naked eyes or using a UV-Vis spectrometer. The sensor revealed a good linear response to ketoprofen enantiomers in the concentration range of 8.33-33.3 μM with a detection limit of 4.52 μM and relative standard deviation of 3.73%. The proposed method was utilized for the determination of ketoprofen racemic mixtures in water samples and commercial tablets. The method excels by its simplicity, low cost, and good availability of materials.
    Matched MeSH terms: Silver
  7. Patients with congenital hypothyroidism demonstrate different altered expression of plasma fibrinogen and haptoglobin polypeptide chains
    Yong PH, Junit SM, Harun F, Hashim OH
    Clin Biochem, 2006 Feb;39(2):126-32.
    PMID: 16412408
    To compare the plasma protein profiles of treated and untreated congenital hypothyroidism (CH) patients with those of normal control infants.
    Matched MeSH terms: Silver
  8. Comparative Efficacy of Antimicrobial Central Venous Catheters in Reducing Catheter-Related Bloodstream Infections in Adults: Abridged Cochrane Systematic Review and Network Meta-Analysis
    Chong HY, Lai NM, Apisarnthanarak A, Chaiyakunapruk N
    Clin Infect Dis, 2017 May 15;64(suppl_2):S131-S140.
    PMID: 28475779 DOI: 10.1093/cid/cix019
    Background: The efficacy of antimicrobial central venous catheters (CVCs) remains questionable. In this network meta-analysis, we aimed to assess the comparative efficacy of antimicrobial CVC impregnations in reducing catheter-related infections in adults.

    Methods: We searched 4 electronic databases (Medline, the Cochrane Central Register of Controlled Trials, Embase, CINAHL) and internet sources for randomized controlled trials, ongoing clinical trials, and unpublished studies up to August 2016. Studies that assessed CVCs with antimicrobial impregnation with nonimpregnated catheters or catheters with another impregnation were included. Primary outcomes were clinically diagnosed sepsis, catheter-related bloodstream infection (CRBSI), and all-cause mortality. We performed a network meta-analysis to estimate risk ratio (RR) with 95% confidence interval (CI).

    Results: Sixty studies with 17255 catheters were included. The effects of 14 impregnations were investigated. Both CRBSI and catheter colonization were the most commonly evaluated outcomes. Silver-impregnated CVCs significantly reduced clinically diagnosed sepsis compared with silver-impregnated cuffs (RR, 0.54 [95% CI, .29-.99]). When compared to no impregnation, significant CRBSI reduction was associated with minocycline-rifampicin (RR, 0.29 [95% CI, .16-.52]) and silver (RR, 0.57 [95% CI, .38-.86]) impregnations. No impregnations significantly reduced all-cause mortality. For catheter colonization, significant decreases were shown by miconazole-rifampicin (RR, 0.14 [95% CI, .05-.36]), 5-fluorouracil (RR, 0.34 [95% CI, .14-.82]), and chlorhexidine-silver sulfadiazine (RR, 0.60 [95% CI, .50-.72]) impregnations compared with no impregnation. None of the studies evaluated antibiotic/antiseptic resistance as the outcome.

    Conclusions: Current evidence suggests that the minocycline-rifampicin-impregnated CVC appears to be the most effective in preventing CRBSI. However, its overall benefits in reducing clinical sepsis and mortality remain uncertain. Surveillance for antibiotic resistance attributed to the routine use of antimicrobial-impregnated CVCs should be emphasized in future trials.

    Matched MeSH terms: Silver/administration & dosage
  9. Pulmonary surfactant mitigates silver nanoparticle toxicity in human alveolar type-I-like epithelial cells
    Sweeney S, Leo BF, Chen S, Abraham-Thomas N, Thorley AJ, Gow A, et al.
    Colloids Surf B Biointerfaces, 2016 Sep 01;145:167-75.
    PMID: 27182651 DOI: 10.1016/j.colsurfb.2016.04.040
    Accompanying increased commercial applications and production of silver nanomaterials is an increased probability of human exposure, with inhalation a key route. Nanomaterials that deposit in the pulmonary alveolar region following inhalation will interact firstly with pulmonary surfactant before they interact with the alveolar epithelium. It is therefore critical to understand the effects of human pulmonary surfactant when evaluating the inhalation toxicity of silver nanoparticles. In this study, we evaluated the toxicity of AgNPs on human alveolar type-I-like epithelial (TT1) cells in the absence and presence of Curosurf(®) (a natural pulmonary surfactant substitute), hypothesising that the pulmonary surfactant would act to modify toxicity. We demonstrated that 20nm citrate-capped AgNPs induce toxicity in human alveolar type I-like epithelial cells and, in agreement with our hypothesis, that pulmonary surfactant acts to mitigate this toxicity, possibly through reducing AgNP dissolution into cytotoxic Ag(+) ions. For example, IL-6 and IL-8 release by TT1 cells significantly increased 10.7- and 35-fold, respectively (P<0.01), 24h after treatment with 25μg/ml AgNPs. In contrast, following pre-incubation of AgNPs with Curosurf(®), this effect was almost completely abolished. We further determined that the mechanism of this toxicity is likely associated with Ag(+) ion release and lysosomal disruption, but not with increased reactive oxygen species generation. This study provides a critical understanding of the toxicity of AgNPs in target human alveolar type-I-like epithelial cells and the role of pulmonary surfactant in mitigating this toxicity. The observations reported have important implications for the manufacture and application of AgNPs, in particular for applications involving use of aerosolised AgNPs.
    Matched MeSH terms: Silver/toxicity*
  10. Green synthesis of graphene-silver nanocomposites and its application as a potent marine antifouling agent
    Yee MS, Khiew PS, Chiu WS, Tan YF, Kok YY, Leong CO
    Colloids Surf B Biointerfaces, 2016 Dec 01;148:392-401.
    PMID: 27639489 DOI: 10.1016/j.colsurfb.2016.09.011
    Fouling of marine surfaces has been a perpetual problem ever since the days of the early sailors. The tenacious attachment of seaweed and invertebrates to man-made surfaces, notably on ship hulls, has incurred undesirable economic losses. Graphene receives great attention in the materials world for its unique combination of physical and chemical properties. Herein, we present a novel 2-step synthesis method of graphene-silver nanocomposites which bypasses the formation of graphene oxide (GO), and produces silver nanoparticles supported on graphene sheets through a mild hydrothermal reduction process. The graphene-Ag (GAg) nanocomposite combines the antimicrobial property of silver nanoparticles and the unique structure of graphene as a support material, with potent marine antifouling properties. The GAg nanocomposite was composed of micron-scaled graphene flakes with clusters of silver nanoparticles. The silver nanoparticles were estimated to be between 72 and 86nm (SEM observations) while the crystallite size of the silver nanoparticles (AgNPs) was estimated between 1 and 5nm. The nanocomposite also exhibited the SERS effect. GAg was able to inhibit Halomonas pacifica, a model biofilm-causing microbe, from forming biofilms with as little as 1.3wt.% loading of Ag. All GAg samples displayed significant biofilm inhibition property, with the sample recording the highest Ag loading (4.9wt.% Ag) associated with a biofilm inhibition of 99.6%. Moreover, GAg displayed antiproliferative effects on marine microalgae, Dunaliella tertiolecta and Isochrysis sp. and inhibited the growth of the organisms by more than 80% after 96h. The marine antifouling properties of GAg were a synergy of the biocidal AgNPs anchored on the stable yet flexible graphene sheets, providing maximum active contact surface areas to the target organisms.
    Matched MeSH terms: Silver/chemistry*
  11. Biogenic integrated ZnO/Ag nanocomposite: Surface analysis and in vivo practices for the management of type 1 diabetes complications
    Rahim Pouran S, Bayrami A, Mohammadi Arvanag F, Habibi-Yangjeh A, Darvishi Cheshmeh Soltani R, Singh R, et al.
    Colloids Surf B Biointerfaces, 2020 May;189:110878.
    PMID: 32087528 DOI: 10.1016/j.colsurfb.2020.110878
    In this research, a milk thistle seed extract (MTSE)-rich medium was used as a capping and reducing agent for the one-pot biosynthesis of ZnO/Ag (5 wt%) nanostructure. The sample was systematically characterized through various techniques and its strong biomolecule‒metal interface structure was supported by the results. The efficacy of the derived nanostructure (MTSE/ZnO/Ag) was evaluated in vivo on the basis of its therapeutic effects on the main complications of Type 1 diabetes (hyperglycemia, hyperlipidemia, and insulin deficiency). For this purpose, the changes in the plasma values of fasting blood glucose, total cholesterol, total triglyceride, high-density lipoprotein cholesterol, and insulin in alloxan-diabetic Wistar male rats were compared with those in healthy and untreated diabetic controls after a treatment period of 16 days. The antidiabetic results of MTSE/ZnO/Ag were compared with those obtained from pristine ZnO, MTSE, and insulin therapies. The health conditions of the rats with Type 1 diabetes were significantly enhanced after treatment with MTSE/ZnO/Ag (p 
    Matched MeSH terms: Silver/chemistry
  12. A Perspective on Therapeutic Applications and Strategies to Mitigate Toxicity of Metallic Nanoparticles
    Karuppaiah A, Selvaraj D, Sellappan M, Nagarajan A, Babu D, Rahman H, et al.
    Curr Pharm Des, 2023;29(4):239-245.
    PMID: 36624648 DOI: 10.2174/1381612829666230109111635
    Metallic nanoparticles (MNPs) have been widely used for diagnostic and therapeutic purposes in clinical practice. A number of MNP formulations are being investigated in clinical trials for various applications. This increase in the use of NPs results in higher exposure to humans, leading to toxicity issues. Hence, it is necessary to determine the possible undesirable effects of the MNPs after in-vivo application and exposure. One of the main reasons for the toxicity of MNPs is the release of their respective metallic ions throughout the body. Many research studies are in progress investigating the various strategies to reduce the toxicity of MNPs. These research studies aim to change the size, dose, agglomeration, release, and excretion rates of MNPs. In this perspective review, we discussed the possible strategies to improve the therapeutic effects of MNPs through various processes, with lessons learned from the studies involving silver nanoparticles (AgNPs). We also discussed the ways to manage the toxicity of MNPs by purification, surface functionalization, synergistic effect, and targeted therapy approach. All these strategies could reduce the dose of the MNPs without compromising their therapeutic benefits, which could decrease the toxicity of MNPs. Additionally, we briefly discussed the market and toxicology testing for FDA-regulated MNPs.
    Matched MeSH terms: Silver
  13. Adducts of triangular silver(i) 3,5-bis(trifluoromethyl)pyrazolate with thiophene derivatives: a weak interaction model of desulfurization
    Liu R, Zhang W, Wei D, Chen JH, Ng SW, Yang G
    Dalton Trans, 2019 Nov 21;48(43):16162-16166.
    PMID: 31651001 DOI: 10.1039/c9dt03344k
    π-Acidic triangular silver(i) 3,5-bis(trifluoromethyl)pyrazolate (Ag3pz3) can form 1 : 1 adducts with dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (DMDBT), benzothiophene (BT), and 2,5-dimethylthiophene (DMT), which are stabilized by weak AgS and AgC contacts and sometimes by π-π stacking and, therefore, may represent a weak interaction model for some adsorptive desulfurization processes.
    Matched MeSH terms: Silver
  14. Fulltext Dataset of SSR markers for ISSR-Suppression-PCR to detect genetic variation in Garcinia mangostana L. in Peninsular Malaysia
    Samsir SA, Bunawan H, Yen CC, Noor NM
    Data Brief, 2016 Sep;8:1438-42.
    PMID: 27617279 DOI: 10.1016/j.dib.2016.08.016
    In this dataset, we present 15 Simple Sequence Repeat (SSR) markers with the motifs (AC)n, (GA)n, and (AC)n(AG)n using a ISSR-Suppression-PCR technique in order to discriminate Garcinia mangostana from diverse geographical origins in Peninsular Malaysia. A few loci showed differences between 3 and 6 bp in allele size, indicating that there are some polymorphisms between individuals correlating to the number of SSR repeats that may be useful for differentiate of genotypes. Collectively, these data show that the ISSR-Suppression-PCR is a valuable method to illustrate genetic variation of selected G. mangostana in Malaysia.
    Matched MeSH terms: Silver
  15. Expression of high-abundance proteins in sera of patients with endometrial and cervical cancers: analysis using 2-DE with silver staining and lectin detection methods
    Abdul-Rahman PS, Lim BK, Hashim OH
    Electrophoresis, 2007 Jun;28(12):1989-96.
    PMID: 17503403
    The expression of high-abundance serum proteins in newly diagnosed patients with endometrial adenocarcinoma (EACa), squamous cell cervical carcinoma (SCCa) and cervical adenocarcinoma (ACCa), relative to control female subjects, was analyzed by subjecting serum samples to 2-DE followed by image analysis of the silver-stained protein profiles. The three cohorts of cancer patients demonstrated different altered expression of serum high-abundance proteins compared to negative control women. The expression of alpha1-antitrypsin, alpha1-B glycoprotein, cleaved high-molecular-weight kininogen (light chain) and antithrombin III were consistently altered in all the patients. However, clusterin was upregulated only in the patients with EACa, while those with SCCa and ACCa were typically characterized by the upregulated expression of zinc alpha-2-glycoprotein. The aberrant expression of selective serum proteins in the various cohorts of cancer patients was validated by competitive ELISA as well as by lectin detection. Analysis by using the champedak galactose binding lectin further highlighted an unidentified protein that may be differently glycosylated in the sera of the EACa patients that were studied.
    Matched MeSH terms: Silver Staining
  16. Modified silver staining in 2DE improves protein detection even at extremely low sample concentration
    Liew YK, Neela V, Hamat RA, Nordin SA, Chong PP
    Electrophoresis, 2013 Feb;34(3):397-400.
    PMID: 23161123 DOI: 10.1002/elps.201200380
    The typical concentration of protein loaded varies from 0.13 to 1.40 μg/μL for a classical silver staining method in 2DE gel. Here, we present a simple modified classical silver staining method by modifying the silver impregnation and development reaction steps. This modified method detects the protein spots at extremely low loaded concentrations, ranging from 0.0048 to 0.0480 μg/μL. We recommend this modified silver staining as an excellent method for the limited biological samples used for silver-stained 2DE analysis. Altogether, the protocol takes close to two days from first dimension separation to second dimension separation, followed by silver staining, scanning, and analysis.
    Matched MeSH terms: Silver Staining/methods*
  17. Fulltext Trophic transfer of silver nanoparticles shifts metabolism in snails and reduces food safety
    Dang F, Li C, Nunes LM, Tang R, Wang J, Dong S, et al.
    Environ Int, 2023 Jun;176:107990.
    PMID: 37247467 DOI: 10.1016/j.envint.2023.107990
    Food security and sustainable development of agriculture has been a key challenge for decades. To support this, nanotechnology in the agricultural sectors increases productivity and food security, while leaving complex environmental negative impacts including pollution of the human food chains by nanoparticles. Here we model the effects of silver nanoparticles (Ag-NPs) in a food chain consisting of soil-grown lettuce Lactuca sativa and snail Achatina fulica. Soil-grown lettuce were exposed to sulfurized Ag-NPs via root or metallic Ag-NPs via leaves before fed to snails. We discover an important biomagnification of silver in snails sourced from plant root uptake, with trophic transfer factors of 2.0-5.9 in soft tissues. NPs shifts from original size (55-68 nm) toward much smaller size (17-26 nm) in snails. Trophic transfer of Ag-NPs reprograms the global metabolic profile by down-regulating or up-regulating metabolites for up to 0.25- or 4.20- fold, respectively, relative to the control. These metabolites control osmoregulation, phospholipid, energy, and amino acid metabolism in snails, reflecting molecular pathways of biomagnification and pontential adverse biological effects on lower trophic levels. Consumption of these Ag-NP contaminated snails causes non-carcinogenic effects on human health. Global public health risks decrease by 72% under foliar Ag-NP application in agriculture or through a reduction in the consumption of snails sourced from root application. The latter strategy is at the expense of domestic economic losses in food security of $177.3 and $58.3 million annually for countries such as Nigeria and Cameroon. Foliar Ag-NP application in nano-agriculture has lower hazard quotient risks on public health than root application to ensure global food safety, as brought forward by the United Nations Sustainable Development Goals.
    Matched MeSH terms: Silver/toxicity; Silver/chemistry
  18. Hydrothermal synthesis and photocatalytic application of ZnS-Ag composites based on biomass-derived carbon aerogel for the visible light degradation of methylene blue
    Shanmugam P, Parasuraman B, Boonyuen S, Thangavelu P, AlSalhi MS, Zheng ALT, et al.
    Environ Geochem Health, 2024 Feb 17;46(3):92.
    PMID: 38367085 DOI: 10.1007/s10653-024-01871-1
    A facile and cost-effective hydrothermal followed by precipitation method is employed to synthesize visible light-driven ZnS-Ag ternary composites supported on carbon aerogel (CA). Extensive studies were conducted on the structural, morphological, and optical properties, confirming the successful formation of ternary nanocomposites. The obtained results evidently demonstrate the successful loading of ZnS and Ag onto the surface of the CA. High-resolution transmission electron microscopy analysis revealed that ZnS and Ag nanoparticles (AgNPs) were uniformly distributed on the surface of the CA with an average diameter of 18 nm. The biomass-derived CA, containing a hierarchical porous nano-architecture and an abundant number of -NH2 functional groups on the surface, can greatly prevent the agglomeration, stability and reduce particle size. Brunauer-Emmett-Teller analysis results indicated specific surface areas of 4.62 m2 g-1 for the CA, 48.50 m2 g-1 for the CA/ZnS composite, and 62.62 m2 g-1 for the CA/ZnS-Ag composite. These values demonstrate an increase in surface area upon the incorporation of ZnS and Ag into the CA matrix. Under visible light irradiation, the synthesized CA/ZnS-Ag composites displayed remarkably improved photodegradation efficiency of methylene blue (MB). Among the tested samples, the CA/ZnS-Ag composites exhibited the highest percentage of photodegradation efficiency, surpassing ZnS, CA, and CA/ZnS. The obtained percentages of degradation efficiency for CA, ZnS, CA/ZnS, and CA/ZnS-Ag composites were determined as 26.60%, 52.12%, 68.39%, and 98.64%, respectively. These results highlight the superior photocatalytic performance of the CA/ZnS-Ag composites in the degradation of MB under visible light conditions. The superior efficiency of the CA/ZnS-Ag composite can be attributed to multiple factors, including its elevated specific surface area, inhibition of electron-hole pair recombination, and enhanced photon absorption within the visible light spectrum. The CA/ZnS-Ag composites displayed consistent efficiency over multiple cycles, confirming their stable performance, reusability, and enduring durability, thereby showcasing the robust nature of this composite material.
    Matched MeSH terms: Silver/chemistry
  19. Modified APHA closed-tube reflux colorimetric method for TOC determination in water and wastewater
    Salihu SO, Bakar NKA
    Environ Monit Assess, 2018 May 30;190(6):369.
    PMID: 29850927 DOI: 10.1007/s10661-018-6727-y
    The analysis of total organic carbon (TOC) by the American Public Health Association (APHA) closed-tube reflux colorimetric method requires potassium dichromate (K2Cr2O7), silver sulfate (AgSO4), and mercury (HgSO4) sulfate in addition to large volumes of both reagents and samples. The method relies on the release of oxygen from dichromate on heating which is consumed by carbon associated with organic compounds. The method risks environmental pollution by discharging large amounts of chromium (VI) and silver and mercury sulfates. The present method used potassium monochromate (K2CrO4) to generate the K2Cr2O7 on demand in the first phase. In addition, miniaturizing the procedure to semi microanalysis decreased the consumption of reagents and samples. In the second phase, mercury sulfate was eliminated as part of the digestion mixture through the introduction of sodium bismuthate (NaBiO3) for the removal of chlorides from the sample. The modified method, the potassium monochromate closed-tube colorimetry with sodium bismuthate chloride removal (KMCC-Bi), generates the potassium dichromate on demand and eliminates mercury sulfate. The semi microanalysis procedure leads to a 60% reduction in sample volume and ≈ 33.33 and 60% reduction in monochromate and silver sulfate consumption respectively. The LOD and LOQ were 10.17 and 33.90 mg L-1 for APHA, and 4.95 and 16.95 mg L-1 for KMCC-Bi. Recovery was between 83 to 98% APHA and 92 to 104% KMCC-Bi, while the RSD (%) ranged between 0.8 to 5.0% APHA and 0.00 to 0.62% KMCC-Bi. The method was applied for the UV-Vis spectrometry determination of COD in water and wastewater. Statistics was done by MINITAB 17 or MS Excel 2016. ᅟ Graphical abstract.
    Matched MeSH terms: Silver/analysis
  20. Green synthesis, characterization and applications of silver nanoparticle mediated by the aqueous extract of red onion peel
    Tan Sian Hui Abdullah HS, Aqlili Riana Mohd Asseri SN, Khursyiah Wan Mohamad WN, Kan SY, Azmi AA, Yong Julius FS, et al.
    Environ Pollut, 2021 Feb 15;271:116295.
    PMID: 33383429 DOI: 10.1016/j.envpol.2020.116295
    This manuscript describes the reuse of biowaste for the biosynthesis of silver nanoparticles (AgNPs) and their applications. In particular, we hypothesized that the phytochemicals in the onion peels could act as reductant for silver nanoparticles syntheses. AgNO3 solution (1 mmol) was added dropwise to an aqueous solution of onion peel extract in 3:7 ratio. The reaction mixture was subjected to heating at 90 °C for about 30 min. During the synthesis of the AgNPs, the change of the colour of solution was observed. The AgNPs solution was centrifuged to obtain the two layers, which consists of clear solution and solid layers at 12000 rpm for 30 min. The precipitate was filtered and was re-dispersed in deionised water (25 mL). The solution was centrifuged again to obtain the purified AgNPs. Subsequently, this solution was freeze dried for 48 h to afford the powdered AgNPs. In this work, the structure of the AgNPs were synthesized in spherical shape, with an average size of 12.5 nm observed in the Transmission electron microscopy (TEM) analysis. For catalytic application, the synthesized AgNPs could be applied as green catalyst to promote Knoevenagel and Hantzsch reactions. In most cases, the desired products were obtained in satisfactory yields. In addition, the AgNPs were found to be recyclable for the subsequent reactions. After five successive runs, the average isolated yields for both transformations were recorded to be 91% (Knoevenagel condensation) and 94% (Hantzsch reaction), which indicated that the existing AgNPs could apply as green catalyst in the field of organic synthesis. Furthermore, the AgNPs also showed satisfactory result in antioxidant activity. The current results indicate that the AgNPs can act as alternative antioxidant agent and green catalyst in mediating organic transformations.
    Matched MeSH terms: Silver*
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