Impact of nanosilver surface electronic distributions on serum protein interaction and hemocompatibility.

Translation of silver-based nanotechnology "from bench to bedside" requires a deep understanding of the molecular aspects of its biological action, which remains controversial at low concentrations and non-spherical morphologies. Here, we present a hemocompatibility approach based on the effect of the distinctive electronic charge distribution in silver nanoparticles (nanosilver) on blood components. On basis of spectroscopic, volumetric, microscopic, dynamic light scattering measurements, pro-coagulant activity tests and cellular inspection we determine that, at extremely low nanosilver concentrations (0.125 - 2.5 µg mL-1) there is a relevant interaction effect on serum albumin and on red blood cells. The explanation has its origin in the surface charge distribution of nanosilver and their electron-mediated energy transfer mechanism. Prism-shaped nanoparticles, with anisotropic charge distributions, act at the surface level generating a compaction of the native protein molecule, while the spherical nanosilver, by exhibiting isotropic surface charge, generates a polar environment comparable to the solvent. Both morphologies induce aggregation at NPs / BSA ≅ 0.044 molar ratio values without altering the coagulation cascade tests, although the spherical-shaped nanosilver has a negative impact on red blood cells. Overall, our results suggest that the electron distributions of nanosilver, even at extremely low concentrations, are a critical factor influencing the molecular structure of blood proteins and red blood cells' membranes. Isotropic forms of nanosilver should be considered with caution, as they are not always the least harmful.

On-demand Opto-Laser activatable nanoSilver ThermoGel for treatment of full-thickness diabetic wound in a mouse model.

Patients suffering from diabetes mellitus are prone to develop diabetic wounds that are non-treatable with conventional therapies. Hence, there is an urgent need of hour to develop the therapy that will overcome the lacunas of conventional therapies. This investigation reports the Quality by Design-guided one-pot green synthesis of unique Opto-Laser activatable nanoSilver ThermoGel (OL→nSil-ThermoGel) for hyperthermia-assisted treatment of full-thickness diabetic wounds in mice models. The characterization findings confirmed the formation of spherical-shaped nanometric Opto-Laser activatable nanoSilver (30.75 ± 2.7 nm; ∆T: 37 ± 0.2 °C â†’ 66.2 ± 0.1 °C; at 1.8 W/cm2 NIR laser density). The findings indicated acceptable in vitro cytocompatibility and significant keratinocyte migration (95.04 ± 0.07 %) activity of OL→nSil towards HaCaT cells. The rheological data of OL→nSil hybridized in situ thermoresponsive gel (OL→nSil-ThermoGel) showed the gelling temperature at 32 ± 2 °C. In vivo studies on full-thickness diabetic wounds in a Mouse model showed OL→nSil-ThermoGel accelerated wound closure (94.42 ± 1.03 %) and increased collagen synthesis, angiogenesis, and decreased inflammatory markers. Similarly, immunohistochemistry study showed significant angiogenesis and faster phenotypic switching of fibroblasts to myofibroblasts in OL→nSil-ThermoGel treated diabetic wounds. Histological evaluation revealed a marked rise in keratinocyte migration, organized collagen deposition, and early regeneration of the epithelial layer compared to the diabetic wound control. In conclusion, the OL→nSil-ThermoGel modulates the cytokines, re-epithelialization, protein expression, and growth factors, thereby improving the repair and regeneration of diabetic wounds in mice.

Incorporating nanosilver with glass ionomer cement-A literature review.

OBJECTIVES: The objectives of this study were to retrieve and review studies that incorporated nanosilver with GIC and summarise the evidence regarding the properties of nanosilver-modified GIC. MATERIALS AND METHODS: Two independent researchers performed a literature search using the keywords (nanosilver OR nano-silver OR (nano silver) OR (silver nanoparticles)) AND (GIC OR (glass ionomer cement) OR (glass ionomer cements)) in PubMed, Web of Science and ScienceDirect. RESULTS: A total of 368 articles were identified. After removing duplicate results, titles and abstracts were screened for eligibility. Full texts of publications that investigated the manufacture and properties of nanosilver-modified GIC were retrieved and analysed. Finally, 21 studies were included. CONCLUSIONS: All of the studies reviewed in this investigation included the incorporation of nanosilver in GIC. The proportions of nanosilver added into GIC varied from 0.05 % to 50 %. Thirteen studies investigated the antimicrobial properties of nanosilver-modified GIC; all studies supported that adding nanosilver enhanced antimicrobial effectiveness. Nineteen studies reported the mechanical properties including compressive strength, flexure strength, tensile strength, and microhardness of nanosilver-modified GIC; but the results were inconclusive. Four studies tested the bonding strength of nanosilver-modified GIC to dentine and found that adding nanosilver would not influence the bonding property of GIC. Some studies explored fluoride release level, colour stability, and cytotoxicity of nanosilver-modified GIC; but the results were all inconclusive. CLINICAL SIGNIFICANCE: This literature review is the first study to retrieve and summarise the findings and evidence regarding nanosilver-modified GIC research. It can provide clinicians with clinically relevant information about novel GIC materials that can be used in their treatment decisions.

A Comparative Evaluation of Nanosilver Fluoride, Chlorhexidine, and Sodium Fluoride When Used as a Varnish on Streptococcus mutans Levels in Children with Caries.

Aim: The purpose of the present study is to evaluate the effect of nanosilver fluoride (NSF), chlorhexidine (CHX), and sodium fluoride (NaF) when used as a varnish on Streptococcus mutans levels in children with dental caries. Study design: A total of 120 children (age range 8-12 years) with incipient caries were randomly assigned to four groups (n = 30): group I-NSF varnish, group II-CHX varnish, group III-NaF varnish, and group IV-control. Varnish application at baseline was performed once. To assess the levels of S. mutans using the culture method [colony-forming units (CFUs)] and optical density (OD), plaque and samples were taken at baseline (T0), 1 month (T1), and 3 months (T3). Additionally, the oral hygiene index-simplified (OHI-S) was noted for clinical assessment. Results: By the end of 3 months, a statistically significant reduction in plaque CFU and salivary CFU was found in group II. At the conclusion of the 3 months, group I had the greatest decrease in OHI-S. After 3 months, the plaque CFU score did not differ significantly across groups I, II, and III. However, a statistically significant difference in OD values (p-value of 0.00) was discovered between group I and all other groups. Conclusion: Children with early caries can effectively lower their S. mutans count by using NSF varnish. How to cite this article: Raja T, Agarwal N, Jabin Z, et al. A Comparative Evaluation of Nanosilver Fluoride, Chlorhexidine, and Sodium Fluoride When Used as a Varnish on Streptococcus mutans Levels in Children with Caries. Int J Clin Pediatr Dent 2024;17(4):410-416.

Evaluation of Remineralization Efficacy of Nanoparticle-based Materials on White Spot Lesions in Children: A Comparative Clinical Study.

Background: Despite the introduction of several anticaries products, dental caries continues to be a global problem. In recent years, there has been a rise in interest in noninvasive treatment for noncavitated caries lesions by employing remineralization concepts. Each remineralizing agent has its own drawbacks. Therefore, it is desirable to seek new agents that offer the advantages of earlier counterparts with lower detrimental reactions. Aim: The purpose of this research is to evaluate the remineralization efficacy of nanoparticle-based materials on white spot lesion (WSL) in children. Materials and methods: A total of 45 children between the age-group of 4 and 8 years with WSLs were selected and randomly divided into three groups. At baseline, the teeth with WSLs were confirmed and identified using International Caries Detection and Assessment System II (ICDAS II) criteria, and the dimensions of the lesions were measured using photographic methods. Then, they were randomly placed into three groups of 15 samples each-group I nanosilver fluoride (NSF), group II nanohydroxyapatite (nano-HAP) serum, and group III MI varnish. Following that, the varnish was applied, and follow-up was done in the 2nd, 4th, 12th, and 24th week. Results: By the 4th week, all three groups had a statistically significant difference (p < 0.05). Baseline measurements for groups I, II, and III showed that their respective mean WSL dimensions were 4.9 ± 0.66, 4.27 ± 0.69, and 5.44 ± 2.95. The dimensions of each group were reduced by the 24th week to 1.22 ± 0.46, 0.93 ± 0.41, and 2.19 ± 1.40, respectively. Overall, group II (nano-HAP serum) showed a statistically significant decrease in the dimension of the lesion at the end of the 24th week, followed by groups I and III. Conclusion: The remineralization of enamel was induced by all three agents. Nano-HAP serum is more successful than MI Varnish and NSF. How to cite this article: Annadurai T, Vundela RR, Chowdhary N, et al. Evaluation of Remineralization Efficacy of Nanoparticle-based Materials on White Spot Lesions in Children: A Comparative Clinical Study. Int J Clin Pediatr Dent 2024;17(4):425-432.

Study on the Antibacterial Activity and Bone Inductivity of Nanosilver/PLGA-Coated TI-CU Implants.

Background: Implants are widely used in the field of orthopedics and dental sciences. Titanium (TI) and its alloys have become the most widely used implant materials, but implant-associated infection remains a common and serious complication after implant surgery. In addition, titanium exhibits biological inertness, which prevents implants and bone tissue from binding strongly and may cause implants to loosen and fall out. Therefore, preventing implant infection and improving their bone induction ability are important goals. Purpose: To study the antibacterial activity and bone induction ability of titanium-copper alloy implants coated with nanosilver/poly (lactic-co-glycolic acid) (NSPTICU) and provide a new approach for inhibiting implant-associated infection and promoting bone integration. Methods: We first examined the in vitro osteogenic ability of NSPTICU implants by studying the proliferation and differentiation of MC3T3-E1 cells. Furthermore, the ability of NSPTICU implants to induce osteogenic activity in SD rats was studied by micro-computed tomography (micro-CT), hematoxylin-eosin (HE) staining, masson staining, immunohistochemistry and van gieson (VG) staining. The antibacterial activity of NSPTICU in vitro was studied with gram-positive Staphylococcus aureus (Sa) and gram-negative Escherichia coli (E. coli) bacteria. Sa was used as the test bacterium, and the antibacterial ability of NSPTICU implanted in rats was studied by gross view specimen collection, bacterial colony counting, HE staining and Giemsa staining. Results: Alizarin red staining, alkaline phosphatase (ALP) staining, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis showed that NSPTICU promoted the osteogenic differentiation of MC3T3-E1 cells. The in vitro antimicrobial results showed that the NSPTICU implants exhibited better antibacterial properties. Animal experiments showed that NSPTICU can inhibit inflammation and promote the repair of bone defects. Conclusion: NSPTICU has excellent antibacterial and bone induction ability, and has broad application prospects in the treatment of bone defects related to orthopedics and dental sciences.

Colloidal chitosan-silver nanoparticles-fluoride nanocomposite as an antibacterial mouthwash against salivary Streptococcus mutans in orthodontic patients (a randomized clinical trial).

OBJECTIVES: This study aimed to synthesize and characterize colloidal chitosan-silver nanoparticles-fluoride nanocomposite (CCAgNPF) and evaluate its efficacy compared to chlorhexidine on salivary Streptococcus mutans in orthodontic patients. MATERIALS AND METHODS: AgNPs stabilized with chitosan were synthesized by chemical reduction of AgNO3. The nanoparticles were characterized with SEM, FTIR, DLS and ICP-OES. The MIC and MBC against S. mutans and IC50 concentration of CCAgNPF were obtained for antibacterial and cytotoxicity evaluations, respectively. For the clinical study, a total of 45 orthodontic patients were divided into three groups of 15 and used the following mouthwashes twice a day for 1 month: CCAgNPF, chlorhexidine 0.2% and the combination of these mouthwashes. The colony count of salivary S. mutans was evaluated before and after using the mouthwashes. The data were analyzed using One-way ANOVA and Tukey's test. RESULTS: Stabilized AgNPs were spherical with a diameter of 25.3 ± 3.3 nm. The MIC, MBC and IC50 of CCAgNPF were 4.42, 8.85 and 18.89 µg/ml. All mouthwashes reduced the salivary S. mutans of the orthodontic patients, however, no significant difference was found between the efficacy of CCAgNPF and chlorhexidine (P-value > 0.05). The best results were achieved by the combination of CCAgNPF and chlorhexidine mouthwashes (P-value < 0.05). CONCLUSION: The CCAgNPF and its combination with chlorhexidine present potent bactericidal, biocompatible and effective anti-carious mouthwashes for orthodontic patients. CLINICAL RELEVANCE: This study proved CCAgNPF as an antibacterial mouthwash with lower cytotoxicity and side effects for patients undergoing orthodontic treatments to maintain oral hygiene and reduce salivary S. mutans.

Silversol® (a Colloidal Nanosilver Formulation) Inhibits Growth of Antibiotic-Resistant Staphylococcus aureus by Disrupting Its Physiology in Multiple Ways.

Antibiotic-resistant strains of Staphylococcus aureus are being viewed as a serious threat by various public health agencies. Identifying novel targets in this important pathogen is crucial to the development of new effective antibacterial formulations. We investigated the antibacterial effect of a colloidal nanosilver formulation, Silversol®, against an antibiotic-resistant strain of S. aureus using appropriate in vitro assays. Moreover, we deciphered the molecular mechanisms underlying this formulation's anti-S. aureus activity using whole transcriptome analysis. Lower concentrations of the test formulation exerted a bacteriostatic effect against this pathogen, and higher concentrations exerted a bactericidal effect. Silversol® at sub-lethal concentration was found to disturb multiple physiological traits of S. aureus such as growth, antibiotic susceptibility, membrane permeability, efflux, protein synthesis and export, biofilm and exopolysaccharide production, etc. Transcriptome data revealed that the genes coding for transcriptional regulators, efflux machinery, transferases, ß-lactam resistance, oxidoreductases, metal homeostasis, virulence factors, and arginine biosynthesis are expressed differently under the influence of the test formulation. Genes (argG and argH) involved in arginine biosynthesis emerged among the major targets of Silversol®'s antibacterial activity against S. aureus.

Evaluation of staining potential of Silver Diamine Fluoride, Potassium Iodide, Nanosilver Fluoride: an in vitro study.

BACKGROUND: The black staining effect of silver-containing solutions for use to arrest caries can have a negative aesthetic impact on children and parents. This study aims to assess the staining effects of Silver Diamine Fluoride/Potassium Iodide (SDF/KI), SDF and Nanosilver Fluoride (NSF). MATERIALS AND METHODS: Forty-four extracted carious primary molars were collected and randomly divided into four groups (n = 11). The carious tissue in all teeth was removed using a chemo-mechanical caries removal agent with an excavator. After caries removal in all groups, SDF, SDF/KI, and NSF were applied to the different groups, while no solution was applied to the control group. Subsequently, the teeth in all groups were restored with compomer. Color values L*, a* and b* were measured using a spectrophotometer at three time points: immediately after compomer restoration (T0), one week later (T1), and four week later (T2). Changes in brightness (ΔL) and color (ΔE) over time were calculated and comparisons among groups were made. RESULTS: The SDF solution induced statistically significant black staining (p = 0.013) and a decrease in L* value (p < 0.001) on the compomer material compared to the other groups over time. CONCLUSIONS: It was observed that SDF/KI has the potential to reduce the black staining effect of SDF, though not entirely. Novel experimental solutions like NSF may offer an alternative to counteract the staining effect of SDF.

Environmental factors modify silver nanoparticles ecotoxicity in Chydorus eurynotus (Cladocera).

Silver nanoparticles (AgNPs) are among the most produced nanomaterials in the world and are incorporated into several products due to their biocide and physicochemical properties. Since freshwater bodies are AgNPs main final sink, several consequences for biota are expected to occur. With the hypothesis that AgNPs can interact with environmental factors, we analyzed their ecotoxicity in combination with humic acids and algae. In addition to the specific AgNPs behavior in the media, we analyzed the mortality, growth, and phototactic behavior of Chydorus eurynotus (Cladocera) as response variables. While algae promoted Ag+ release, humic acids reduced it by adsorption, and their combination resulted in an intermediated Ag+ release. AgNPs affected C. eurynotus survival and growth, but algae and humic acids reduced AgNPs lethality, especially when combined. The humic acids mitigated AgNP effects in C. eurynotus growth, and both factors improved its phototactic behavior. It is essential to deepen the study of the isolated and combined influences of environmental factors on the ecotoxicity of nanoparticles to achieve accurate predictions under realistic exposure scenarios.

Developing a novel glass ionomer cement with enhanced mechanical and chemical properties.

OBJECTIVE: To develop a novel glass ionomer cement (NGIC) with enhanced mechanical and chemical properties and assess its biocompatibility, mechanical strength, and ion release. METHODS: Nanosilver doped bioactive glass (NanoAg BAG) was synthesized by sol-gel method and characterized by scanning electron microscopy with energy-dispersive X-ray spectroscopy and transmission electron microscopy. The NanoAg BAG, together with poly(vinylphosphonic acid) (PVPA), alumino-fluorosilicate glass and poly-acrylic acid were used to synthesize NGIC. The optimal PVPA concentration for NGIC was determined by PVPA modified GIC's biocompatibility and mechanical properties and used to prepare NGIC specimens. NGIC specimens with NanoAg BAG at 0%, 1%, 2%, and 5% were allocated into Groups NGIC0, NGIC1, NGIC2, and NGIC5, respectively. The biocompatibility, surface morphology, elemental composition, surface topography, chemical properties, compressive strength, diametral tensile strength, and ion release of the NGIC were assessed. A conventional glass ionomer cement (GIC) was used as a control. RESULTS: A granular BAG with nano silver particles attached on its surface were found, indicating the successful synthesis of NanoAg BAG. PVPA at 10% presented the best effect in enhancing the biocompatibility and mechanical properties of PVPA modified GIC and was used to prepare NGIC specimens. NGIC1 showed similar biocompatibility, surface morphology and topography to GIC. Chemical properties results showed that NGICs showed the same adsorption peaks to GIC. The compressive strength (mean±SD in MPa) was 168.1 ± 29.7, 205.5 ± 29.5, 221.8 ± 46.8, 216.6 ± 59.3 and 167.7 ± 36.4, and the diametral tensile strength (mean±SD in MPa) was 14.1 ± 1.7, 18.3 ± 4.9, 21.2 ± 2.2, 17.2 ± 3.8 and 13.3 ± 3.3 for GIC, NGIC0, NGIC1, NGIC2 and NGIC5 respectively. NIGC0, NGIC1 and NGIC2 showed higher compressive and diametral tensile strength than GIC (p < 0.01). NGIC2 and NGIC5 showed higher release of fluoride, calcium, phosphate and silver ion than GIC and NGIC0 (p < 0.05). CONCLUSION: A biocompatible NGIC with enhanced mechanical properties were developed. It presented enhanced fluoride, calcium, phosphate and silver ion release compared to conventional GIC.

Antibacterial effects of silver diamine fluoride, potassium iodide and nanosilver fluoride on dual-species biofilm.

OBJECTIVES: This study aims to evaluate antibacterial effects of silver diamine fluoride (SDF), SDF/potassium iodide (KI), and nanosilver fluoride (NSF). METHODS: Antimicrobial activity of sterile saline, 5% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), SDF, SDF/KI, NSF, and KI solutions against Streptococcus mutans and Lactobacillus casei was assessed through disc diffusion tests. A dual-species biofilm of S. mutans-L. casei was formed on 48 enamel samples, divided into six groups (n = 8). Group 1 was treated with sterile saline, Group 2 with 5% NaOCl, Group 3 with 2% CHX, Group 4 with SDF, Group 5 with SDF/KI, and Group 6 with NSF. The samples were analysed using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Statistical analysis utilized Shapiro-Wilk and Kruskal-Wallis tests and multiple comparisons were conducted using Dunn test. RESULTS: SDF, SDF/KI, and NaOCl displayed significantly higher antibacterial activity against dual-species biofilm compared to NSF and CHX (p < 0.050). CONCLUSIONS: In conclusion, SDF and SDF/KI demonstrated greater antibacterial activity than NSF. SDF's antibacterial activity was unaffected by KI. Further research is needed to determine the appropriate content and concentration for achieving effective antibacterial activity with NSF. CLINICAL SIGNIFICANCE: The use of silver-containing materials is increasing in popularity within pediatric dentistry. In this study, an endeavor has been made to assist pediatric dentists in determining which solution might be more advantageous for preventing caries.

Unraveling the immune response of the spleen in sepsis using green-synthesized silver nanoparticles from pomegranate peel extracts.

Sepsis is a serious disease characterized by an inappropriate host response to infection, resulting in widespread inflammation and systemic organ failure. The aim of this research is to investigate the possibility of pomegranate peel-derived silver nanoparticles (PGNP) as a potential alternative therapy for sepsis. Characterization using transmission electron microscopy revealed 10-30 nm spherical nanoparticles. In a rat model of sepsis, PGNP treatment improved spleen health, histology, and immune response as compared with septic rats. In rats treated with PGNP during sepsis, significant alterations in oxidative stress markers (p < .01) were observed. These included elevated levels of glutathione (0.63 ± 0.08 mmol/mg protein), reduced concentrations of nitric oxide (8.7 ± 0.8 µ mol/mg protein) and malondialdehyde (2.2 ± 0.3 nmol/mg protein), as well as increased activity of superoxide dismutase (159 ± 33 U/mg protein). Following PGNP administration, gene expression analysis revealed a decrease in spleen IL-1ß, IL-6, and TNF-α, highlighting its anti-inflammatory potential. Furthermore, PGNP effectively controlled apoptosis-related genes (Bax, Bcl-2, and Casp3), indicating its role in cellular survival pathways. This study sheds light on the immunological regulation of the spleen during sepsis using PGNP, demonstrating its potential as a new effective treatment approach. The study emphasizes the necessity of continuing to investigate and develop alternative medicines, particularly in light of antibiotic resistance and the global impact of sepsis. RESEARCH HIGHLIGHTS: The study explored the potential medicinal benefits of pomegranate peel-derived silver nanoparticles (PGNP) in the treatment of sepsis. PGNP suppressed pro-inflammatory cytokines and enhanced the immune response. The study recommends PGNP as a viable substitute treatment.

Green Method for the Preparation of Durable Superhydrophobic Antimicrobial Polyester Fabrics with Micro-Pleated Structures.

To produce functional protective textiles with minimal environmental footprints, we developed durable superhydrophobic antimicrobial textiles. These textiles are characterized by a micro-pleated structure on polyester fiber surfaces, achieved through a novel plasma impregnation crosslinking process. This process involved the use of water as the dispersion medium, water-soluble nanosilver monomers for antimicrobial efficacy, fluorine-free polydimethylsiloxane (PDMS) for hydrophobicity, and polyester (PET) fabric as the base material. The altered surface properties of these fabrics were extensively analyzed using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectrometry (XPS), thermogravimetric analysis (TGA), and water contact angle (WCA) measurements. The antimicrobial performance of the strains was evaluated using Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. After treatment, the fabrics exhibited enhanced hydrophobic and antimicrobial properties, which was attributed to the presence of a micro-pleated structure and nanosilver. The modified textiles demonstrated a static WCA of approximately 154° and an impressive 99.99% inhibition rate against both test microbes. Notably, the WCA remained above 140° even after 500 washing cycles or 3000 friction cycles.

Attenuation of photosynthesis in nanosilver-treated Arabidopsis thaliana is inherently linked to the particulate nature of silver.

Silver nanoparticles (AgNPs) are known to affect the physiology and morphology of plants in various ways, but the exact mechanism by which they interact with plant cells remains to be elucidated. An unresolved question of silver nanotoxicology is whether the interaction is triggered by the physical features of the particles, or by silver ions leached from their surface. In this study, we germinated and grew Arabidopsis thaliana seedlings in synthetic medium supplemented with sub-morbid concentrations (4 µg/mL) of AgNPs and silver nitrate (AgNO3). This treatment led to in planta accumulation of 106 µg/g and 97 µg/g of silver in the AgNO3- and AgNP-exposed seedlings, respectively. Despite the statistically indistinguishable silver accumulation, RNA sequencing data demonstrated distinct changes in the transcriptome of the AgNP-exposed, but not in the AgNO3-exposed plants. AgNP exposure induced changes in the expression of genes involved in immune response, cell wall organization, photosynthesis and cellular defense against reactive oxygen species. AgNO3 exposure, on the other hand, caused the differential expression of only two genes, neither of which belonged to any AgNP-enriched gene ontology categories. Moreover, AgNP exposure led to a 39% reduction (p < 0.001) in total chlorophyll concentration relative to untreated plants which was associated with a 56.9% and 56.2% drop (p < 0.05) in carbon assimilation rate at ambient and saturating light, respectively. Stomatal conductance was not significantly affected by AgNP exposure, and limitations to carbon assimilation, as determined through analysis of light and carbon dioxide (A/Ci) curves, were attributed to rates of electron transport, maximum carboxylation rates and triose phosphate use. AgNO3-exposure, on the other hand, did not lead to significant reduction either in chlorophyll concentration or in carbon assimilation rate. Given these data, we propose that the impact of AgNPs cannot be simply attributed to the presence of the metal in plants, but is innate to the particulate nature of nanosilver.

Preparation of CS-LS/AgNPs Composites and Photocatalytic Degradation of Dyes.

Synthetic dyes are prone to water pollution during use, jeopardizing biodiversity and human health. This study aimed to investigate the adsorption and photocatalytic assist potential of sodium lignosulfonate (LS) in in situ reduced silver nanoparticles (AgNPs) and chitosan (CS)-loaded silver nanoparticles (CS-LS/AgNPs) as adsorbents for Rhodamine B (RhB). The AgNPs were synthesized by doping LS on the surface of chitosan for modification. Fourier transform infrared (FT-IR) spectrometry, energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to confirm the synthesis of nanomaterials. The adsorption and photocatalytic removal experiments of RhB were carried out under optimal conditions (initial dye concentration of 20 mg/L, adsorbent dosage of 0.02 g, time of 60 min, and UV power of 250 W), and the kinetics of dye degradation was also investigated, which showed that the removal rate of RhB by AgNPs photocatalysis can reach 55%. The results indicated that LS was highly effective as a reducing agent for the large-scale production of metal nanoparticles and can be used for dye decolorization. This work provides a new catalyst for the effective removal of dye from wastewater, and can achieve high-value applications of chitosan and lignin.

Silver compounds used in pediatric dentistry for caries arrest: A review of current materials and new technologies.

Silver compounds have been used in medicine and dentistry for centuries. Their use in pediatric dentistry has long been restricted because of some drawbacks, chief among them being the discoloration of teeth with black stains. However, recent advances in technology have resulted in the development of new silver agents that do not have the limitations of previously used ones. This led to the reintroduction of silver compounds in pediatric dentistry. The aim of the present review was to examine the evidence supporting the therapeutic use of silver compounds in pediatric dentistry for caries arrest, as well as the mode of action and biocompatibility, characteristics, advantages, and disadvantages of different silver-containing agents.

The effect of nano silver fluoride, self-assembling peptide and sodium fluoride varnish on salivary cariogenic bacteria: a randomized controlled clinical trial.

OBJECTIVES: To compare the antibacterial effect of Nanosilver Fluoride varnish (NSF) varnish, P11-4 and Sodium Fluoride (NaF) varnish against salivary Streptococcus mutans (S. mutans) and Lactobacilli. METHODS: 66 patients aged 10-24 years old were randomly assigned to receive single application of NSF, P11-4 or NaF varnish. Baseline unstimulated saliva samples were collected before the agents were applied and S.mutans and Lactobacilli colony forming units (CFU) were counted. After one, three and six months, microbiological samples were re-assessed. Groups were compared at each time point and changes across time were assessed. Multivariable linear regression compared the effect of P11-4 and NSF to NaF on salivary S. mutans and Lactobacilli log count at various follow up periods. RESULTS: There was a significant difference in salivary S. mutans log count after 1 month between P11-4 (B= -1.29, p = 0.049) and NaF but not at other time points nor between NSF and NaF at any time point. The significant reduction in bacterial counts lasted up to one month in all groups, to three months after using P11-4 and NaF and returned to baseline values after six months. CONCLUSION: In general, the antimicrobial effect of P11-4 and NSF on salivary S. mutans and Lactobacilli was not significantly different from NaF varnish. P11-4 induced greater reduction more quickly than the two other agents and NSF antibacterial effect was lost after one month. CLINICAL RELEVANCE: NSF varnish and P11-4 have antimicrobial activity that does not significantly differ from NaF by 3 months. P11-4 has the greatest antibacterial effect after one month with sustained effect till 3 months. The antibacterial effect of NSF lasts for one month. NaF remains effective till 3 months. TRIAL REGISTRATION: This trial was prospectively registered on the clinicaltrials.gov registry with ID: NCT04929509 on 18/6/2021.

Cytocompatibility, antibacterial, and corrosion properties of chitosan/polymethacrylates and chitosan/poly(4-vinylpyridine) smart coatings, electrophoretically deposited on nanosilver-decorated titania nanotubes.

The development of novel implants subjected to surface modification to achieve high osteointegration properties at simultaneous antimicrobial activity is a highly current problem. This study involved different surface treatments of titanium surface, mainly by electrochemical oxidation to produce a nanotubular oxide layer (TNTs), a subsequent electrochemical reduction of silver nitrate and decoration of a nanotubular surface with silver nanoparticles (AgNPs), and finally electrophoretic deposition (EPD) of a composite of chitosan (CS) and either polymethacrylate-based copolymer Eudragit E 100 (EE100) or poly(4-vinylpyridine) (P4VP) coating. The effects of each stage of this multi-step modification were examined in terms of morphology, roughness, wettability, corrosion resistance, coating-substrate adhesion, antibacterial properties, and osteoblast cell adhesion and proliferation. The results showed that the titanium surface formed nanotubes (inner diameter of 97 ± 12 nm, length of 342 ± 36 nm) subsequently covered with silver nanoparticles (with a diameter of 88 ± 8 nm). Further, the silver-decorated nanotubes were tightly coated with biopolymer films. Most of the applied modifications increased both the roughness and the surface contact angle of the samples. The deposition of biopolymer coatings resulted in reduced burst release of silver. The coated samples revealed potent antimicrobial activity against both Gram-positive and Gram-negative bacteria. Total elimination (99.9%) of E. coli was recorded for a sample with CS/P4VP coating. Cytotoxicity results using hFOB 1.19, a human osteoblast cell line, showed that after 3 days the tested modifications did not affect the cellular growth according to the titanium control. The proposed innovative multilayer antibacterial coatings can be successful for titanium implants as effective postoperative anti-inflammation protection.

Escherichia coli isolates from meat and abattoirs environment in Egypt: molecular characterization and control by nanosilver particles.

Three hundred samples, including meat from the slaughtered carcass and water, air samples, and swabs from the floor, wall, and employees' hands, were collected from five municipal abattoirs spread across several Egyptian provinces. The Escherichia coli was isolated from floor swabs, meat, air, wall, hand, and water samples. Serotyping of the recovered isolates clarified the presence of various serotypes, including enterohemorrhagic serotypes (O111: H4, O128: H2, and O127: H6) and enterotoxigenic serotypes (O44: H18 and O125: H21). The isolates were resistant to cefotaxime (100%), amoxiclav (80%), then rifampin (66.7%). The stx1 gene, stx2 gene, eaeA gene, blaCMY2 gene and iss gene were detected in 10-80 % of the isolates. Nanosilver (AgNPs) showed that 12.5 ppm was the lowest concentration that prevented bacterial growth. It was observed that 12% of workers wore a clean white coat, only 24% washed their hands between activities during work, only 14% used soap for hand washing, and 42% utilized the same knife for meat and its offal.