Silver Citrate Research Articles

Bifunctional NiFe-LDH@AgCit nanocomposite-based immunosensor for electrochemical and colorimetric detection of SARS-CoV-2

The COVID-19 pandemic caused by SARS-CoV-2 has precipitated a global public health emergency, necessitating the urgent development of rapid and accurate virus detection methods. Compared with the current single-signal detection methods commonly used, dual-mode detection has inherent self-verification and self-correction functions and is expected to provide more reliable and interference-resistant detection results. In this work, a rapid approach for SARS-CoV-2 detection was developed using an electrochemical and colorimetric immunosensor based on a NiFe layered double hydroxide (LDH) loaded with silver citrate (NiFe-LDH@AgCit). The electrochemical sensor is capable of measuring the electrical signal of the transition from Ag to Ag+ in the presence of SARS-CoV-2. At the same time, the color reaction of 3,3′,5,5′-tetramethylbenzidine with ⋅OH can be used to build a colorimetric sensor. In electrochemical and colorimetric sensing systems, the linear detection ranges were 0.0005–10 and 0.001–10 ng mL−1, respectively. The corresponding limits of detection reached as low as 0.167 and 0.333 pg mL−1, respectively. In addition, the dual-signal sensor has been favorably used for the detection of SARS-CoV-2 in human serum, and the recovery ranges were 99.0 %–101.6 % and 100.6 %–104.5 %, respectively. In conclusion, the proposed dual-signal sensing technique offers novel insights for the prompt diagnosis of virus-related illnesses, which has wide application prospects.

Effect of 17% ethylenediaminetetraacetic acid and silver citrate on sealer resin penetration in the apical third

Effect of 17% ethylenediaminetetraacetic acid and silver citrate on sealer resin penetration in the apical third

Coral-like silver citrate as robust laccase mimetics in a novel colorimetric aptasensor for sensitive and highly selective detection of histamine in food

The colorimetric methods for histamine detection still face some challenges in accuracy and stability. Herein, a novel colorimetric aptasensor for sensitive and highly selective detection of histamine was developed based on the enhancement of silver citrate (AgCit) laccase-mimic activity. It has been confirmed that H2 aptamer enhances the affinity of AgCit to the chromogenic substrate, and promotes the generation of semiquinone radical in the laccase-mimic catalytical system. The color change of the sensing solution can be distinguished by the naked eye, and easily converted to the corresponding RGB value by a smartphone for the quantitative and rapid detection of histamine. The aptasensor has a limit of detection (LOD) as low as 27 μg L−1, and maintains high selectivity for histamine in the presence of other competitive substances. It is strongly believed that the design of a colorimetric aptasensor can provide a simple and versatile platform for histamine detection in food.

Effects of Silver Citrate Prolonged Exposure on Behavioral and Cognitive Functions of Mice

Pure silver as well as silver compounds have been used as antiseptics for centuries. Nowadays, the most frequently applied silver compounds are silver nanoparticles. Several studies demonstrate the ability of silver nanoparticles and silver salts to accumulate in the brain of laboratory animals as well as the ability of silver nanoparticles to influence behavioral and cognitive functions of laboratory mammals. For the first time, the influence of silver citrate on the change dynamics of behavioral and cognitive functions of laboratory mice at the daily oral exposure during 30, 60, 120, and 180 days were investigated in the present research. We observed the anxiety increase after 30 days of the exposure as well as the ability of mice to adapt to the prolonged oral exposure of silver citrate manifested in the anxiety decrease, increase of locomotor activity and the tendency of long-term contextual memory improvement at the further stages of the experiment. Increase of locomotor activity and memory improvement might be associated with the sensitivity increase and regarded as compensatory mechanism to anxiety increase. The observed phenomenon is classified as a hormetic effect. A comparison with the analogous study, which implemented polyvinylpyrrolidone coated silver nanoparticles, is carried out. It was concluded that the nanoscale impacts into the toxicity of silver compound.

Effect of Final Irrigation Solutions on Mechanical Properties of Root Canal Dentine Running title: Final Irrigation on Mechanical Properties.

The final irrigation solution should have the capability of a chelation agent to remove the smear layer. The purpose of this study was to determine the effect of EDTA, novel silver citrate, and chitosan nanoparticles as a final irrigation solution on the mechanical properties of root canal dentine, namely the flexural strength and elastic modulus. Thirty-two intact, single, and straight roots, with no caries, no cracks, and no restoration of premolars, were assigned into four groups of 8 teeth each. Group 1: irrigated with EDTA; Group 2: irrigated with novel silver citrate; Group 3: irrigated with chitosan nanoparticles; Group 4: irrigated with saline as control. Using a Universal Testing Machine, each sample was tested for flexural strength and elastic modulus with a three-point bend test. The data were analysed using one-way ANOVA and followed by the Tukey's test with a significance level of 95%. Chitosan nanoparticles generated the highest flexural strength and elastic modulus of root canal dentine (212.03 +- 1.64 and 16.40 +- 1.05, respectively) than EDTA (127.10 +- 0.90 and 7.37 +- 0.94) and novel silver citrate (177.87 +- 2.03, and 12.27 +- 1.01) (p<0.05). However, chitosan nanoparticles have similar flexural strength and elastic modulus of root canal dentine when compared to saline (213.76 +- 1.48, 17.02 +- 1.14, respectively) (p>0.05). Among final irrigations used, chitosan nanoparticles produced the highest flexural strength and elastic modulus of root canal dentine compared to EDTA and novel silver citrate.

Colorimetric sensor and visual enzyme sheets for sensitive detection of dimethoate residue in vegetables based on laccase-like activity of coral-like silver citrate

The overutilization of dimethoate may lead to its deposition in both the environment and crops, which potentially induces neurological, respiratory, and hepatic abnormalities upon absorption by organisms. Colorimetry can accurately determine dimethoate, but there are still many challenges in the rapid, convenient, and point-of-care detection. Herein, based on the inhibitory effect of dimethoate on the laccase activity of silver citrate (AgCit), a smartphone-assisted colorimetric sensor and rapid detection enzyme sheets were constructed. It was demonstrated that dimethoate could adsorb on the surface of AgCit and inhibit the production of semiquinone radicals in the reaction system. Then, the AgCit laccase activity was inhibited, causing the colorimetry sensor and the enzyme sheets turned light red or even colorless. The constructed sensor has higher sensitivity and the limit of detection for dimethoate is 1.0 μg⋅L−1. Moreover, the developed enzyme sheets have good selectivity and specificity, and display the detection results within 5 min. Thus, the colorimetric sensor and the constructed enzyme sheets are expected to be used for large-scale preliminary detection of dimethoate residues in actual agricultural products.

Antimicrobial properties and skin compatibility of a new emollient (body lotion) containing octenidine and silver citrate for atopic skin

Antimicrobial properties and skin compatibility of a new emollient (body lotion) containing octenidine and silver citrate for atopic skin

Improved barrier function and skin acceptability of a new cosmetic (body lotion) for atopic-prone skin containing octenidine and silver citrate as antimicrobial agents

Improved barrier function and skin acceptability of a new cosmetic (body lotion) for atopic-prone skin containing octenidine and silver citrate as antimicrobial agents

The role of citrate in heterogeneous silver metal catalyst formation: A mechanistic consideration

The formation of silver particles as initial catalyst for the electroless copper deposition is an essential part of the formation of conductive structures in flexible electronics. In this work, we have investigated the basic mechanism using the citrate anion for the fixation of silver species and later metal catalyst formation directly on a textile substrates surface. During the particle formation process and the subsequent electroless copper deposition, silver changes its oxidation state several times. While the decomposition of bulk silver citrate leads to silver metal, the distribution on the substrate surface leads to silver oxide due to the oxidation under air. Finally, the reducing conditions in the copper deposition step, i.e. alkaline formaldehyde, convert any silver-ion to silver metal. In parallel, the thermal decomposition of silver citrate also forms CO2 and hexane-2,5-dione. The latter is the result of an auto oxidation reaction similar to Kolbe electrolysis, i.e. symmetrical radical recombination of two acetonyl radicals remaining from the decarboxylated citrate scaffold.

Evaluation of Effects of Various Irrigating Solutions on Chemical Structure of Root Canal Dentin Using FTIR, SEM, and EDS: An In Vitro Study.

Background: Sequential chemical application for irrigating a root canal during chemomechanical debridement can affect the dentin microstructure. Understanding the effects of various irrigants on chemical properties of dentin can elucidate their effects on physical properties and thereby explain the higher incidence of structural failure in endodontically treated teeth. This in vitro research aimed to compare and evaluate the effects of three different irrigating solutions on the chemical structure of root canal dentin in extracted human teeth. Methods: Forty-eight extracted single-rooted mandibular premolar teeth were sectioned at the cemento–enamel junction by a diamond disc and were then randomly assigned to four groups of twelve samples each. The groups were irrigated using 5.25% NaOCl, ozonated olive oil, silver citrate, or distilled water. Dentin sections measuring 1.5 mm were obtained from the root portion and each section and were analyzed using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and electron-dispersive spectroscopy (EDS). FTIR and EDS values are reported as means ± standard deviations. Data were analyzed using an ANOVA and a post hoc Bonferroni test (p < 0.05). Results: A comparison of the FTIR and EDS values among the groups using ANOVA revealed statistically significant differences in the organic and inorganic peak values among the groups. An intergroup comparison between NaOCl with silver citrate and ozonated olive oil revealed significant reductions in the carbonate and phosphate peak values in the NaOCl group (p < 0.05). The EDS values tabulated for the carbon, oxygen, phosphorous, and calcium peak levels showed significant differences between the groups using an ANOVA. An SEM analysis was conducted under 1500× magnification, which revealed smear layer removal in the silver citrate group. Conclusions: The silver citrate solution and the ozonated olive oil caused less changes in the organic and mineral contents of dentin than sodium hypochlorite.

In vitro and in vivo antimicrobial activity of an active plant-based quadrocomplex for skin hygiene

Context: The current epidemiological situation causes a new surge of interest to perspective antimicrobial formulations for proper skin hygiene. Aims: To evaluate in vitro and in vivo the antimicrobial activity of a novel active quadrocomplex (QC) for skin hygiene based on Melaleuca alternifolia essential oil, eucalyptol, (-)-α-bisabolol and silver citrate. In addition, to analyze the phytochemical constituents by gas chromatography-mass spectrometry (GC-MS) and to assess the skin irritant potential after regular washing. Methods: The phytochemical analysis was performed using GC-MS. The Minimum Inhibitory Concentrations (MICs) were assessed using a colony-counting method with resazurin. The type of pharmacological interaction was investigated using a modern checkerboard assay. Results: The chemical composition exhibited 18 resolved phytochemicals with the highest concentrations for (-)-α-bisabolol (32.2%) and terpinen-4-ol (31.6%) through the GC-MS analysis. QC agents showed antimicrobial activity against Gram-positive and Gram-negative strains, with MIC values ranging from 1.25 to 40.00 mg/mL. The checkerboard assay demonstrated reduced MIC values for the combinations of QC agents against all reference strains. QC showed significant inhibition of Staphylococcus aureus growth with an average efficiency of 99.91% and Candida albicans 99.94 %. In vivo, the investigation of QC showed higher immediate and prolonged efficiency compared to base formulation (p&lt;0.05). Dermatology evaluation indicated that QC added to the soap base did not affect the skin of hands during regular hand-washing and did not cause any negative effects on the skin. Conclusions: QC exhibits a balanced performance between antimicrobial activity and biological safety and can be considered a promising bioactive composition for regular hand hygiene application. Therefore, additional investigations are needed to study the mechanism of antimicrobial activity.

Study of Physico-Chemical Interactions during the Production of Silver Citrate Nanocomposites with Hemp Fiber.

In the study presented in this paper, the results obtained by producing nanocomposites consisting of a silver citrate thin layer deposited on hemp fiber surfaces are analyzed. Using the pulsed laser deposition (PLD) method applied to a silver target with impurities of nickel and iron, the formation of the silver citrate film is performed in various ways and the results are discussed based on Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy coupled with Energy Dispersive X-ray (SEM-EDX) spectroscopy analyses. A mechanism of the physico-chemical processes that take place based on the FTIR vibrational modes and the elemental composition established by the SEM-EDS analysis is proposed. Inhibition of the fermentation process of Saccharomyces cerevisae is demonstrated for the nanocomposite material of the silver citrate thin layer, obtained by means of the PLD method, on hemp fabric. The usefulness of composite materials of this type can extend from sensors and optoelectronics to the medical fields of analysis and treatment.

A single-nanozyme colorimetric array based on target-induced differential surface passivation for quantification and discrimination of Cl−, Br− and I− ions

Abnormal levels of halide ions in drinking water have enormous threats to human health, and thus designing reliable and sensitive methods to quantify and distinguish these ions becomes extremely crucial. Herein, we develop a single-nanozyme colorimetric array based on target-induced differential surface passivation for the quantification and discrimination of Cl−, Br− and I− ions. Silver citrate (Ag3Cit) is designed as an oxidase mimic to efficiently catalyze the 3,3′,5,5′-tetramethylbenzidine (TMB) chromogenic reaction. When halide ions (Cl−, Br− and I−) are present, due to their different precipitation interactions with the Ag(Ⅰ) entity in Ag3Cit, they can passivate the active surface of the nanozyme to various degrees, resulting in the inhibited TMB chromogenic reaction differentially. According to this principle, simple and efficient quantitative detection of Cl−, Br− and I− ions was achieved, with all the detection limits down to the nM level. By employing Ag3Cit as a single sensing element, a nanozyme catalysis-based colorimetric array was further established, and both individual and mixed ions were successfully distinguished by integrating the array with principal component analysis. Accurate identification of unknown samples was also verified via a double-blind protocol, indicating potential applications of the array in practice.

‘Laccase-like’ properties of coral-like silver citrate micro-structures for the degradation and determination of phenolic pollutants and adrenaline

Laccases are multicopper containing oxidase enzymes that are highly important in environmental remediation and biotechnology. To date, complex Copper containing materials have been reported as laccase mimic, and the possibility of a non-Cu laccase mimic remained unknown. In this work, we report an exceptionally simple functional laccase mimic based on coral-like silver citrate (AgCit) microstructures. The AgCit was synthesized by a simple precipitation method and was found to possess excellent laccase-like activity capable of oxidizing phenolic substrates and the endocrine hormone adrenaline. Compared to the natural laccase enzyme, our reported laccase-mimic has a higher υmax and lower Km value using adrenaline as a substrate. In addition, the AgCit laccase mimic was observed to be stable at extreme pH, higher temperature, and suitable for long-term storage at room temperature. The laccase-like properties of the AgCit nanozyme were successfully applied for the quantification and degradation of various phenolic pollutants and the adrenaline hormone.

Heterogeneous nucleation in citrate synthesis of AgNPs: Effect of mixing and solvation dynamics

The heterogeneity issues in silver nanoparticle nucleation (Lee-Meisel route) have been investigated. The final polydispersity and sphericity of the nanoparticles in the Lee-Meisel scheme are shown to depend upon the early time dynamics of silver-citrate complexation. The formation of macromolecular intermediary complexes in the early stages of the reaction is visualized based on online DLS data, TEM analysis, and the mass balances of silver and citrate ions. The reversible complexation between citrate ions and silver citrate is shown to be the limiting step that governs the directional growth of the nanoparticles. The dynamics of the complexation of citrate are seen to form a very rapid step and intense mixing was required for the complexation to happen uniformly across the reaction. This specific observation is also confirmed from the MD simulations. Thus, to get particles of high sphericity, irrespective of the reaction concentration, temperature, or reactor geometry, the mixing time should be <4 s and Da ~ 0.1. Optimal mixing conditions for isotropic growth are suggested based on the reaction kinetics and are also demonstrated with experimental evidence.

Evaluation of Cytotoxicity and Antibacterial Activity of a New Class of Silver Citrate-Based Compounds as Endodontic Irrigants.

In the present study, the cytotoxicity and the antimicrobial activity of two silver citrate-based irrigant solutions were investigated. Cytotoxicity of various concentrations (0.25%, 0.5%, 1%, 2.5%, 5%) of both solutions (BioAKT and BioAKT Endo) was assessed on L-929 mouse fibroblasts using the MTT assay. For the quantitative analysis of components, an infrared (I.R.) spectroscopy was performed. The minimum inhibitory and minimal bactericidal concentrations (M.I.C. and M.B.C., respectively) were ascertained on Enterococcus faecalis strain ATCC 4083. For biofilm susceptibility after treatment with the irrigating agent, a minimum biofilm eradication concentration (M.B.E.C.) and confocal laser scanning microscope (C.L.S.M.) assays were performed. Quantification of E. faecalis cell biomass and percentage of live and dead cells in the biomass was appraised. Normality of data was analyzed using the D’Agostino & Pearson’s test and the Shapiro–Wilk test. Statistical analysis was performed using one-way analysis of variance (ANOVA) and Tukey’s test. Both silver citrate solutions showed mouse fibroblasts viability >70% when diluted to 0.25% and 0.5%. Conversely, at higher concentrations, they were extremely cytotoxic. F.T.-IR spectroscopy measurements of both liquids showed the same spectra, indicating similar chemical characteristics. No substantial contrast in antimicrobial activity was observed among the two silver citrate solutions by using broth microdilution methods, biofilm susceptibility (MBEC-HTP device), and biomass screening using confocal laser scanning microscopy (C.L.S.M.) technique. Both solutions, used as root canal irrigants, exhibited significant antimicrobial activity and low cytocompatibility at dilutions greater than 0.5%.

Experimental justification of the efficacy of Zn and Ag citrates in bird bacterioses

Experimental justification of the efficacy of Zn and Ag citrates in bird bacterioses

Silver Citrate Nanoparticles Inhibit PMA-Induced TNFα Expression via Deactivation of NF-κB Activity in Human Cancer Cell-Lines, MCF-7.

BackgroundThe nuclear factor kappa-B (NF-κB) is a major transcription factor responsible for the production of numerous inflammatory mediators, including the tumor necrosis factor (TNFα), which has a lethal association with cancer’s onset. The silver nanoparticles (AgNPs) are widely used in cancer treatment and several other biomedical applications.ObjectiveThe study aimed to determine the effects of silver citrate nanoparticles (AgNPs-CIT) on NF-κB activation together with TNFα mRNA/protein expressions in the phorbol myristate acetate (PMA)-stimulated MCF-7 human breast cancer cell-lines.MethodsThe AgNPs-CIT were synthesized by the reduction method, and the prepared AgNPs-CIT were characterized for their shape, absorption in UV-VIS electromagnetic radiations, size distribution, ζ-potential, and antioxidant activity. The MCF-7 cell-lines were pretreated with AgNPs-CIT and stimulated with PMA. The TNFα mRNA expressions were determined by real-time PCR, whereas the protein production was determined by the ELISA. The NF-κB activity was distinctly observed by highly-specific DNA-based ELISA, and by NF-κB-specific inhibitor, Bay 11–7082.ResultsThe prepared AgNPs-CIT were spherical and have an absorption wavelength range of 381–452 nm wherein the particles size ranged between 19.2±0.1 to 220.77±0.12 nm with the charge range −9.99±0.8 to −34.63±0.1 mV. The prepared AgNPs-CIT showed comparative antioxidant activity at >40% inhibitions level of the DPPH radicals. The AgNPs-CIT were found to be non-toxic to MCF-7 cell-lines and inhibited PMA-induced activation of the NF-κBp65, and also the mRNA/protein expression of TNFα.ConclusionThis is the first report that showed AgNPs-CIT inhibited TNFα expression via deactivation of the NF-κB signaling event in stimulated breast cancer cells. The results have important implications for the development of novel therapeutic strategies for the prevention/treatment of cancers and/or inflammatory disorders.

In situ syntheses of silver nanoparticles inside silver citrate nanorods via catalytic nanoconfinement effect

Although it is still worth to use silver nanoparticles as antimicrobial agents, silver nanoparticles can also be dangerous to human body, when they used directly to the wound sites. One strategy for avoiding this problem is to embed the nanoparticles in matrices such as hydrogels, polymers, or composites; however, most methods have limitations in terms of nanoparticle loading efficiency and/or pre- or post-treatment required in the manufacturing process. Herein, we introduce two in-situ synthetic methods in which silver nanoparticles are directly synthesized inside silver citrate nanorods that are antimicrobial materials composed of silver and citrate ions. The silver nanoparticles embedded antimicrobial silver citrate nanorods are expected to exhibit a synergistic, long―lasting, and sustainable antimicrobial effect. In addition, this study shows that a large number of nanoparticles can be formed inside silver citrate nanorods with no additional reagents not only at temperatures much lower (as low as 25 °C) than those usually required but also rapidly via electron beam irradiation. The fundamental principles of the proposed efficient syntheses are discussed in terms of the catalytic effect of reactants confined in nanospaces.

Дослідження антимікробної дії розчину міді і цитрату срібла за ентеробактеріозів бджіл

Дослідження антимікробної дії розчину міді і цитрату срібла за ентеробактеріозів бджіл