Effect of hyaluronic acid-stabilized silver nanoparticles on lettuce (Lactuca sativa L.) seed germination.

Nanotechnology has brought significant advancements to agriculture through the development of engineered nanomaterials (ENPs). Silver nanoparticles (AgNPs) capped with polysaccharides have been applied in agricultural diagnostics, crop pest management, and seed priming. Hyaluronic acid (HA), a natural polysaccharide with bactericidal properties, has been considered a growth regulator for plant tissues and an inducer of systemic resistance against plant diseases. Additionally, HA has been employed as a stabilizing agent for AgNPs. This study investigated the synthesis and effects of hyaluronic acid-stabilized silver nanoparticles (HA-AgNPs) as a seed priming agent on lettuce (Lactuca sativa L.) seed germination. HA-AgNPs were characterized using several techniques, exhibiting spherical morphology and good colloidal stability. Germination assays conducted with 0.1, 0.04, and 0.02 g/L of HA-AgNPs showed a concentration-dependent reduction in seed germination. Conversely, lower concentrations of HA-AgNPs significantly increased germination rates, survival, tolerance indices, and seed water absorption compared to silver ions (Ag+). SEM/EDS indicated more significant potential for HA-AgNPs internalization compared to Ag+. Therefore, these findings are innovative and open new avenues for understanding the impact of Ag+ and HA-AgNPs on seed germination.

Immobilization of silver-loaded graphene oxide (Ag-GO) on canvas fabric support for catalytic conversion of 4 nitrophenol.

Due to the rising human population and industrialization, harmful chemical compounds such as 4-nitrophenol (4-NP) and various dyes are increasingly released into the environment, resulting in water pollution. It is essential to convert these harmful chemicals into harmless compounds to mitigate this pollution. This research focuses on synthesizing a novel heterogeneous catalyst using modified canvas fabric (CF) decorated with silver metal nanoparticles on graphene oxide nanosheets (Ag-GO/CF). The process involves coating the fabrics (CF) with graphene oxide (GO) nanosheets through sonication. Subsequently, silver nanoparticles are deposited in situ and reduced on the GO surface, resulting in the formation of the Ag-GO/CF composite. Various physicochemical characterizations were conducted to examine the interfacial interactions between CF, GO, and Ag nanoparticles. The catalytic activity of the nanocomposite was assessed by hydrogenating 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride (NaBH4). The results showed that the 10%Ag-5%GO/CF with a surface of 6 cm2 (3 × 2 cm) exhibited the highest catalytic activity, achieving a reduction efficiency of over 96% in 5 min. The 4-NP reduction reaction rate was well-fitted with a pseudo-first-order kinetics model with an apparent reaction rate constant (Kapp) of 0.676 min-1. Furthermore, the Ag-GO/CF composite demonstrated remarkable stability over successive cycles, with no noticeable decrease in its catalytic activity, suggesting its promising application for long-term chemical catalytic processes. This synthesized composite can be easily added to and removed from the reaction solution while maintaining high catalytic performance in the reduction of 4-NP, and it could be beneficial in avoiding problems related to powder separation.

Tiny silver bullets: silver nanoparticles are insecticidal to Culicoides sonorensis (Diptera: Ceratopogonidae) biting midge larvae.

Insecticide formulations with safer environmental profiles and limited off-target effects are desirable to manage medical and veterinary pests. Silver nanoparticles are insecticidal against mosquitos, nonbiting midges, and other insects. The biting midge, Culicoides sonorensis Wirth and Jones, is a vector of agriculturally important pathogens in much of the United States, and this study aimed to examine the insecticidal properties of silver nanoparticles in larvae of this species. Mortality of third-instar larvae was assessed daily for 7 days after exposure to concentrations of silver nanoparticles, sorghum polymer particles, and hybrid silver-sorghum polymer particles. Both silver nanoparticles and silver-sorghum polymer particles were insecticidal, but sorghum polymer particles alone did not significantly contribute to larval mortality. Concentrations of 100 mg/liter of silver nanoparticles achieved >50% mortality at day 7, and 200 mg/liter treatments achieved >75% larval mortality within 24 h. The antimicrobial properties of silver nanoparticles were also examined, and culturable bacteria were recovered from larval-rearing media at 200 mg/liter but not at 400 mg/liter of silver nanoparticles. These data suggest that C. sonorensis larval mortality is primarily caused by silver nanoparticle toxicity and not by the reduction of bacteria (i.e., a larval food source). This work describes the first use of silver nanoparticles in C. sonorensis and shows the potential insecticide applications of these nanoparticles against this agricultural pest. The grain-polymer particles also successfully carried insecticidal silver nanoparticles, and their utility in loading diverse compounds could be a novel toxin delivery system for biting midges and similar pests.

Design of silver nanoparticle-embedded nano zirconium-based metal-organic frameworks for highly sensitive detection of chlorpyrifos in real samples.

Chlorpyrifos (CPS) is widely found in food and water sources due to agricultural use, posing health and environmental risks. Therefore, this work introduces a fluorescent sensor design of silver nanoparticle-embedded nano zirconium-based metal-organic frameworks (UiO-66-NH2@AgNPs) for accurate examination of CPS. Briefly, UiO-66-NH2 was synthesized hydrothermally, exhibiting weak luminescence owed to ligand-to-metal charge transfer (LMCT). Here, it limits its direct utility in fluorescence-based detection. To address this limitation, silver nanoparticles (AgNPs) were introduced into UiO-66-NH2, enhancing fluorescence via the metal-enhanced fluorescence (MEF) effect. Briefly, a comprehensive spectral analysis such as XPS, SEM, TEM, PXRD, etc., was performed to validate the synthesis of UiO-66-NH2@AgNPs. Subsequent evaluation revealed that CPS effectively quenched the luminescence intensity of UiO-66-NH2@AgNPs through a static quenching mechanism. The fluorescence intensity exhibited good linearity with CPS concentration in the span of 10 to 1,000 ng/mL, with a recognition limit of 191.5 ng/mL(S/N = 3). The interaction involved Ag-S bond formation and electrostatic interactions, reducing fluorescence intensity. The method was confirmed through successful CPS detection in fruit samples. The UiO-66-NH2@AgNPs nanoprobe offers a simple, sensitive, and accurate platform for CPS sensing, with potential for future use in detecting CPS in fruits and vegetables.

A Hierarchical Nano to Micro Scale Modelling of 3D Printed Nano-Reinforced Polylactic Acid: Micropolar Modelling and Molecular Dynamics Simulation.

Fused deposition modelling (FDM) is an additive manufacturing technique widely used for rapid prototyping. This method facilitates the creation of parts with intricate geometries, making it suitable for advanced applications in fields such as tissue engineering, aerospace, and electronics. Despite its advantages, FDM often results in the formation of voids between the deposited filaments, which can compromise mechanical properties. However, in some cases, such as the design of scaffolds for bone regeneration, increased porosity can be advantageous as it allows for better permeability. On the other hand, the introduction of nano-additives into the FDM material enhances design flexibility and can significantly improve the mechanical properties. Therefore, modelling FDM-produced components involves complexities at two different scales: nanoscales and microscales. Material deformation is primarily influenced by atomic-scale phenomena, especially with nanoscopic constituents, whereas the distribution of nano-reinforcements and FDM-induced heterogeneities lies at the microscale. This work presents multiscale modelling that bridges the nano and microscales to predict the mechanical properties of FDM-manufactured components. At the nanoscale, molecular dynamic simulations unravel the atomistic intricacies that dictate the behaviour of the base material containing nanoscopic reinforcements. Simulations are conducted on polylactic acid (PLA) and PLA reinforced with silver nanoparticles, with the properties derived from MD simulations transferred to the microscale model. At the microscale, non-classical micropolar theory is utilised, which can account for materials' heterogeneity through internal scale parameters while avoiding direct discretization. The developed mechanical model offers a comprehensive framework for designing 3D-printed PLA nanocomposites with tailored mechanical properties.

Optimisation of a Microwave Synthesis of Silver Nanoparticles by a Quality by Design Approach to Improve SERS Analytical Performances.

A major limitation preventing the use of surface-enhanced Raman scattering (SERS) in routine analyses is the signal variability due to the heterogeneity of metallic nanoparticles used as SERS substrates. This study aimed to robustly optimise a synthesis process of silver nanoparticles to improve the measured SERS signal repeatability and the protocol synthesis repeatability. The process is inspired by a chemical reduction method associated with microwave irradiation to guarantee better controlled and uniform heating. The innovative Quality by Design strategy was implemented to optimise the different parameters of the process. A preliminary investigation design was firstly carried out to evaluate the influence of four parameters selected by means of an Ishikawa diagram. The critical quality attributes were to maximise the intensity of the SERS response and minimise its variance. The reaction time, temperature and stirring speed are critical process parameters. These were optimised using an I-optimal design. A robust operating zone covering the optimal reaction conditions (3.36 min-130 °C-600 rpm) associated with a probability of success was modelled. Validation of this point confirmed the prediction with intra- and inter-batch variabilities of less than 15%. In conclusion, this study successfully optimised silver nanoparticles by a rapid, low cost and simple technique enhancing the quantitative perspectives of SERS.

Self-activated hydrogel cascade reactor integrated with glucose oxidase and silver nanoparticle for enhanced treatment of bacterial infection.

The recognition of silver nanoparticles (AgNPs) as a nanozyme with peroxidase-like activity has offered a promising solution to address the challenges of bacterial resistance and argyria risk. However, the catalytic efficacy of AgNPs is limited by the need for a strong acidic environment and high concentrations of hydrogen peroxide (H2O2). In this work, we developed a self-activated hydrogel cascade reactor (AUGP) for enhanced treatment of bacterial infection. The AUGP integrates the properties of glucose oxidase (GOx) and polyacrylamide (pAAm) hydrogel microsphere. The confinement effect of pAAm hydrogel microsphere enables glucose oxidation to occur in a confined space, which creates an acidic environment to activate AgNPs activity, initiating the cascade reaction between GOx and AgNPs. Meanwhile, the confinement effect facilitates the accumulation of a high local concentration of H2O2, allowing AUGP to generate hydroxyl radicals (•OH) without the need for external H2O2. Additionally, the release of Ag+ from AUGP is achieved upon the generation of •OH. The synergistic action of Ag+ and •OH confers exceptional antibacterial efficacy to AUGP. Importantly, the etching effect of H2O2 ensures the absence of any residual AgNPs, reducing the risk of argyria. In vivo studies validated the efficacy of AUGP in wound disinfection with minimal toxicity.

Speciation-specific chromium bioaccumulation and detoxification in fish using hydrogel microencapsulated biogenic nanosilver and zeolite synergizing with biomarkers.

Grass carp intestinal waste-mediated biosynthesized nanosilver (AgNPs) was valorized using guaran and zeolite matrices, resulting in AgNPs-guaran, AgNPs-zeolite, and AgNPs-guaran -zeolite composites. The valorized products were examined using Environmental Scanning Electron Microscopy, Energy Dispersive X-ray analysis and X-ray Diffraction analysis to confirm uniform dispersion and entrapment of AgNPs within the matrixes. These valorized products were evaluated for their efficacy in detoxifying the ubiquitous and toxic hexavalent chromium (Cr6+) in aquatic environments, with Anabas testudineus exposed to 2 mg l-1 of Cr6+ for 60 days. Remarkable reduction of Cr6+ concentration to 0.86 ± 0.007 mg l-1 was achieved with AgNPs-guaran-zeolite composite, indicating successful reclamation of contaminated water and food safety assurance. Consistency in results was further corroborated by minimal stress-related alterations in fish physiological parameters and integrated biomarker response within the experimental group treated with the AgNPs-guaran-zeolite composite. Despite observed chromium accumulation in fish tissues, evidence of physiological stability was apparent, potentially attributable to trivalent chromium accumulation, serving as an essential nutrient for the fish. Additionally, the challenge study involving Anabas testudineus exposed to Aeromonas hydrophila exhibited the lowest cumulative mortality (11.11%) and highest survival rate (87.5%) within the same experimental group. The current study presents a novel approach encompassing the valorization of AgNPs for Cr6+ detoxification under neutral to alkaline pH conditions, offering a comprehensive framework for environmental remediation.

Improving pressure ulcer care in intensive care units: Evaluating the impact of bundled care and silver nanoparticle dressings.

BACKGROUND: Pressure ulcer (PU) are prevalent among critically ill trauma patients, posing substantial risks. Bundled care strategies and silver nanoparticle dressings offer potential solutions, yet their combined effectiveness and impact on patient satisfaction remain insufficiently investigated. AIM: To assess the impact of bundled care along with silver nanoparticle dressing on PUs management and family satisfaction in critically ill trauma patients. METHODS: A total of 98 critically ill trauma patients with PUs in intensive care unit (ICU) were included in this study. Patients were randomly assigned to either the control group (conventional care with silver nanoparticle dressing, n = 49) or the intervention group (bundled care with silver nanoparticle dressing, n = 49). The PU Scale for Healing (PUSH) tool was used to monitor changes in status of pressure injuries over time. Assessments were conducted at various time points: Baseline (day 0) and subsequent assessments on day 3, day 6, day 9, and day 12. Family satisfaction was assessed using the Family Satisfaction ICU 24 questionnaire. RESULTS: No significant differences in baseline characteristics were observed between the two groups. In the intervention group, there were significant reductions in total PUSH scores over the assessment period. Specifically, surface area, exudate, and tissue type parameters all showed significant improvements compared to the control group. Family satisfaction with care and decision-making was notably higher in the intervention group. Overall family satisfaction was significantly better in the intervention group. CONCLUSION: Bundled care in combination with silver nanoparticle dressings effectively alleviated PUs and enhances family satisfaction in critically ill trauma patients. This approach holds promise for improving PUs management in the ICU, benefiting both patients and their families.

Antibacterial efficacy and osteogenic potential of mineral trioxide aggregate-based retrograde filling material incorporated with silver nanoparticle and calcium fluoride.

Background/purpose: The retrograde filling material, particularly mineral trioxide aggregate (MTA) employed in apicoectomy, should possess high antibacterial efficacy and osteogenic potential. We evaluated the antibacterial efficacy, biocompatibility, and osteogenic potential following the addition of silver nanoparticles (AgNPs) and calcium fluoride (CaF2) in retrograde filling material of MTA. Materials and methods: MTA was mixed with four different solvents. Group 1 (G1): distilled water, Group 2 (G2): 50 ppm AgNPs, Group 3 (G3): 1 wt% CaF2, and Group 4 (G4): 50 ppm AgNPs and 1 wt% CaF2. The pH variation of each group was monitored, while the surface roughness was measured. The antibacterial efficacy against Enterococcus faecalis (E. faecalis) and the viability of murine pre-osteoblast (MC3T3) were evaluated for each group using colorimetric assays. The gene expression levels of osteogenic potential marker (OCN, ALPL, and RUNX2) in MC3T3 cells for each group were quantified using real-time-qPCR. Statistical analysis was performed at α = 0.05 level of significance. Results: When comparing the levels of antibacterial efficacy, the order of effectiveness was G4>G2>G3>G1 (P < 0.05). In the cell viability test, owing to MTA-eluted growth medium having a positive effect on MC3T3 cell proliferation, G1-4 exhibited a statistically increased cell viability compared to the control (P < 0.05). However, G2-4 did not result in a statistically significant difference when compared to G1 (P < 0.05). Moreover, G4 exhibited the highest gene expression among the four groups (P < 0.05). Conclusion: The addition of AgNPs and CaF2 to MTA could be a promising option for use as a new retrograde filling material.

Antibacterial Silver Nanoparticle Containing Polydopamine Hydrogels That Enhance Re-Epithelization.

A polydopamine polyelectrolyte hydrogel was developed by ionic crosslinking dextran sulfate with a copolymer of polyethyleneimine and polydopamine. Gelation was promoted by the slow hydrolysis of glucono-δ-lactone. Within this hydrogel, silver nanoparticles were generated in situ, ranging from 25 nm to 200 nm in size. The antibacterial activity of the hydrogel was proportional to the quantity of silver nanoparticles produced, increasing as the nanoparticle count rose. The hydrogels demonstrated broad-spectrum antibacterial efficacy at concentrations up to 108 cells/mL for P. aeruginosa, K. pneumoniae, E. coli and S. aureus, the four most prevalent bacterial pathogens in chronic septic wounds. In ex vivo studies on human skin, biocompatibility was enhanced by the presence of polydopamine. Dextran sulfate is a known irritant, but formulations with polydopamine showed improved cell viability and reduced levels of the inflammatory biomarkers IL-8 and IL-1α. Silver nanoparticles can inhibit cell migration, but an ex vivo human skin study showed significant re-epithelialization in wounds treated with hydrogels containing silver nanoparticles.

Hepatotoxicity of silver nanoparticles: Benchmark concentration modeling of an in vitro transcriptomics study in human iPSC-derived hepatocytes.

Despite two decades of research on silver nanoparticle (AgNP) toxicity, a safe threshold for exposure has not yet been established, albeit being critically needed for risk assessment and regulatory decision-making. Traditionally, a point-of-departure (PoD) value is derived from dose response of apical endpoints in animal studies using either the no-observed-adverse-effect level (NOAEL) approach, or benchmark dose (BMD) modeling. To develop new approach methodologies (NAMs) to inform human risk assessment of AgNPs, we conducted a concentration response modeling of the transcriptomic changes in hepatocytes derived from human induced pluripotent stem cells (iPSCs) after being exposed to a wide range concentration (0.01-25 µg/ml) of AgNPs for 24 h. A plausible transcriptomic PoD of 0.21 µg/ml was derived for a pathway related to the mode-of-action (MOA) of AgNPs, and a more conservative PoD of 0.10 µg/ml for a gene ontology (GO) term not apparently associated with the MOA of AgNPs. A reference dose (RfD) could be calculated from either of the PoDs as a safe threshold for AgNP exposure. The current study illustrates the usefulness of in vitro transcriptomic concentration response study using human cells as a NAM for toxicity study of chemicals that lack adequate toxicity data to inform human risk assessment.

SNaP-C: Validation of a novel, selective silver nanoparticle antioxidant capacity assay for Vitamin C content in beverages.

A validated silver nanoparticle assay (SNaP-C) for quantitation of Vitamin C, as ascorbic acid (AA) and total AA (TAA), was applied to 31 beverages. SNaP-C assay results (LOD of 2.2 mg/L AA) were compared to AA and TAA determined by high-performance liquid chromatography with UV/Vis (LOD = 0.4 mg/L AA), and two well-known assays. All approaches were calibrated using meta-phosphoric acid stabilized AA, where the reducing agent tris(2-carboxyethyl) phosphine hydrochloride was added to convert dehydroascorbic acid to AA for determination of TAA. Statistical comparisons of these four resulting datasets were completed. SNaP-C and HPLC were not statistically significantly different (P > 0.05) for comparison of AA and TAA (mg/L) in these samples, whereas the CUPRAC and Folin-Ciocalteu assays statistically significantly overestimated values of AA and TAA content, respectively. The SNaP-C method is a novel assay that has high specificity for AA capable of quantifying TAA with addition of TCEP.

Phytochemical Analysis of Silver Nanoparticles of Psidium guajava Leaf Extract and Evaluation for Its Antibacterial Property.

Nonessential heavy metals are toxic to human health. In this study, mercury, a hazardous metal, was detected by colorimetric analysis using Murraya koenigii. The eco-friendliness of this method was also emphasized. UV spectrum is a broad peak observed at 200-250 nm in P. guajava leaf extracts. The UV spectrum of green synthesized P. guajava exhibited an absorption band of 418 nm, which confirms the nanoparticle synthesis. FTIR analysis of the vibrational peak around 3307 cm-1 is assigned to ν(O-H) stretching that could possibly emanate from carbohydrates or phenolics. The peaks found around 2917 and 2849 cm-1 are ascribed to the -C-H stretch of the alkyl group, and the peak around 1625 cm-1 is due to the enolic ß-diketones or -C = O stretch of carboxylic acids, while the corresponding -C-O stretch is observed around 1375 and 1029 cm-1. The assignment of peaks is similar. It is clear from the SEM image that the constituent parts were non-uniform sphere-shaped, agglomerated, and of an average size of 30.9 nm. XRD analysis was utilized to determine the structural characteristics and crystalline nature of P. guajava. The observed intensity peaks at 32.35°, 36.69°, 39.24°, 44.76°, 59.42°, and 67.35° represent the 2θ values for P. guajava in the diffraction pattern, aligning with the values in the standard database. The synthesized AgNPs tested antibacterial properties against various strains of microorganisms, including Escherichia coli, 25 µg/mL 6.02 ± 0.17 and 100 µg/mL 7.3 ± 0.05, Staphylococcus aureus, 25 µg/mL 05.02 ± 0.07 and 100 µg/mL 11.3 ± 1.12, Streptococcus mutans, 25 µg/mL 04.02 ± 0.19 and 100 µg/mL 11.1 ± 0.11, Enterococcus faecalis, 25 µg/mL 0.8.05 ± 0.11 and 100 µg/mL 11.7 ± 0.02. The short novelty of Psidium guajava (guava) lies in its potential relevance to human health, as it has been found to possess bioactive compounds with various medicinal properties, such as antimicrobial, antioxidant, and anti-inflammatory activities, making it a promising natural resource for therapeutic applications.

Pharmacological Effect of In Vitro Antioxidant Property and Green Synthesis of Silver Nanoparticles (AgNPs) Utilizing Murraya koenigii Antibacterial Application.

Background: Nonessential heavy metals pose a significant threat to human health due to their toxicity. Mercury, in particular, is identified as a hazardous metal. The study aims to detect mercury using colorimetric analysis with Murraya koenigii, emphasizing the eco-friendliness of the method. Aims and Objectives: The primary objective is to detect mercury using a colorimetric analysis method employing Murraya koenigii. Additionally, the study aims to investigate the eco-friendliness of this detection method. Materials and Methods: Colorimetric analysis was conducted using Murraya koenigii to detect mercury. Ultraviolet-visible (UV-vis) spectroscopy was employed to detect the formation of silver nanoparticles (AgNPs), with a characteristic surface plasmon resonance (SPR) band observed. X-ray diffraction (XRD) data analysis was performed to determine the crystalline nature and size of AgNPs. Scanning electron microscopy (SEM) was utilized to visualize the morphology of AgNPs. Fourier transform infrared (FTIR) spectroscopy was employed to identify functional groups involved in reducing silver ions. Antibacterial properties of synthesized AgNPs were tested against various microorganisms, including Escherichia coli, Staphylococcus aureus, Streptococcus mutans, and Enterococcus faecalis. Results: Mercury was successfully detected using colorimetric analysis with Murraya koenigii. Formation of AgNPs was confirmed by UV-vis spectroscopy, with a characteristic SPR band at 418 nm. AgNPs were found to be crystalline with an average size of 5.20 nm, as determined by XRD analysis. SEM images revealed spherical and polycrystalline AgNPs. FTIR spectra indicated the involvement of the -OH group of compounds in the extract in reducing silver ions. Synthesized AgNPs exhibited antibacterial properties against various microorganisms. Conclusion: A sustainable and eco-friendly method for synthesizing AgNPs using Murraya koenigii extract was successfully developed. This method not only detected mercury but also demonstrated antibacterial properties against various microorganisms. The study underscores the health implications of nonessential heavy metals, emphasizing the importance of eco-friendly detection and mitigation methods.

Green Synthesis of Ganoderma Lucidum-Mediated Silver Nanoparticles and its Microbial Activity against Oral Pathogenic Microbes: An In Vitro Study.

Nanotechnology is developing into a fast-expanding discipline with applications in science and technology, and nanostructures are a crucial research tool in many fields. Due to their remarkable electrical, optical, magnetic, catalytic, and pharmacological capabilities, metal and metal oxide nanoparticles (NPs) have drawn study interest. Natural elements (plants, microorganisms, fungi, etc.) are utilized in a chemical-free, environmentally benign way to synthesize metals and metal oxides. The optical, electrical, and antimicrobial qualities of silver nanoparticle (AgNP) make them a popular choice. More than 200 active ingredients, including water-soluble, organic-soluble, and volatile chemicals, are found in Ganoderma. The main components are polysaccharides, adenosine, and terpenoids, each of which has exceptional therapeutic properties. This article explains the synthesis of Ag NPs by Ganoderma lucidum and tests the antibacterial effectiveness for use in biological applications.

Efficacy of silver-impregnated fabric in preventing spread of infection in the wrestling environment.

CONTEXT: The best practice for cleaning wrestling mats is using a residual disinfectant with continued antibacterial action. Recently available wash-in silver additives claim to confer a residual effect to fabric. OBJECTIVE: To test the efficacy of laundering with a wash-in silver additive in reducing exposure of athletes to potentially infectious microbes on apparel. DESIGN: 4-part Controlled Laboratory Study/Parallel Group Comparison Study: (1) To test whether fabrics in athletic clothing would be affected differently, we applied bacteria to control fabrics washed in detergent alone and test counterparts washed in detergent plus wash-in silver additive. Bacteria were applied to fabrics, extracted, plated, incubated, and counted. (2) To see if wash-in silver affected various bacteria differently, we washed cotton t-shirts with detergent alone or with detergent plus wash-in silver. We applied four bacterial species commonly found in the wrestling environment. Bacteria were extracted, plated, incubated, and counted. (3) To see if wash-in silver was effective in reducing bacterial contamination during practice, 32 collegiate wrestlers paired off with one wearing a test silver-treated t-shirt, and their partner wearing a control shirt. Wrestler rotations exposed shirts to 2, 4 or 8 wrestlers. Identical swatches of fabric were cut from the t-shirts. Bacteria were extracted, plated, incubated, and counted. (4) We simulated prolonged/repeated bacterial exposure as occurs during tournaments by applying bacteria directly to silver-treated and untreated singlet material repeatedly over time. Test samples were taken at regular intervals to see if bacterial growth was inhibited by the presence of the silver nanoparticles. Bacteria were extracted, plated, incubated, and counted. SETTING: Laboratory and practice. PARTICIPANTS: Collegiate D3 Wrestling Team. MAIN OUTCOME MEASURE(S): Wash-in silver would be considered effective if statistically significant reduction in bacterial count was observed at 95% confidence. RESULTS: Wash-in silver reduced bacterial growth at low levels of contamination but did not significantly reduce bacterial growth at levels seen during contact sport competitions. This was true for all bacterial species and all fabrics tested. CONCLUSIONS: The environmental and potential health risks in using a wash-in silver nanoparticle laundry additive in the wash cycle for clothing worn by wrestlers outweigh any potential infection control benefits to these athletes. We do not currently recommend adopting wash-in silver treatment as part of the laundering regimen for wrestling programs until further testing of alternate methods of silver impregnation into sports fabrics has been investigated.

Superior In Vivo Wound-Healing Activity of Biosynthesized Silver Nanoparticles with Nepeta cataria (Catnip) on Excision Wound Model in Rat.

Silver nanoparticles were biosynthesized with Nepeta cataria plant extract. It was determined that the synthesized Nc-AgNPs gave a strong absorbance peak at 438 nm wavelength in the UV-vis spectrophotometer. SEM and TEM analyses of Nc-AgNPs showed that the synthesized nanoparticles had a spherical morphology. Based on XRD analysis, the average crystallite size of Nc-AgNPs was calculated at 15.74 nm. At the same time, EDS spectrum analysis exhibited dominant emission energy at 3 keV, indicative of Nc-AgNPs. Nc-AgNPs showed an inhibition zone of 12 nm in gram-negative Escherichia coli, 10 nm in gram-positive Enterococcus faecalis, and 11 nm in Staphylococcus aureus. Nc-AgNPs showed high antioxidant properties, with 63% at 5000 µg/mL. The wound-healing properties of Nc-AgNPs were evaluated in vivo in wound models created in a total of 20 Wistar albino male rats, divided into four groups. After 10 days of treatment, the highest wound closure rate was seen in the Nc-AgNP + Vaseline (Group IV) treatment group, at 94%. It was observed that Nc-AgNP + Vaseline nanoformulation significantly increased wound healing, similar to Silverdin®, and Vaseline alone supported healing but did not result in complete closure. Histopathological examination revealed an increase in mature Type 1 collagen in Group IV and positive control (Group II), with better collagen maturation in vehicle control (Group III) compared to negative control (Group I). Immunohistochemical analysis showed complete epithelialization in Group IV and Group II, with distinct cytokeratin expressions, while Group III exhibited mild expressions.

Comparative Evaluation of the Flexural Strength of Heat-Activated Polymethyl Methacrylate Denture Base Resin With and Without 0.2% by the Weight of Silver Nanoparticles Cured by Conventional and Autoclave Methods: An In Vitro Study.

PURPOSE: Heat-activated polymethyl methacrylate (PMMA) is the most common and widely accepted denture base material. Two important drawbacks are the development of denture stomatitis and the high incidence of fracture of denture bases. The present study investigated the effect of adding 0.2% by weight of silver nanoparticles (AgNps) and using the autoclave method of terminal boiling on the flexural strength of heat-activated PMMA denture base resin. METHODS: A total of 40 samples of heat-activated PMMA blocks were divided into four groups, with 10 samples (n = 10) in each group. Group 1 consisted of unmodified heat-activated PMMA resin (PMMA-1) polymerized by the conventional method of terminal boiling (conventional curing); Group 2 consisted of 0.2% by weight AgNPs added to heat-activated PMMA resin (PMMA-2) polymerized by conventional curing; Group 3 consisted of PMMA-1 polymerized by the autoclave method of terminal boiling (autoclave curing); and Group 4 consisted of PMMA-2 polymerized by autoclave curing. The flexural strength was tested using a universal testing machine. Descriptive statistics were expressed as mean ± SD and median flexural strength. Kruskal-Wallis ANOVA with Mann-Whitney U post hoc test was applied to test for statistical significance between the groups. The level of significance was set at p<0.05. RESULTS: The results showed a statistically significant reduction in flexural strength in Group 2 compared to Group 1. The samples from Group 4 showed a statistically significant increase in flexural strength compared to Group 2. The Group 4 denture base had the highest flexural strength (115.72 ± 7.27 MPa) among the four groups, followed by Group 3 (104.16 ± 4.85 MPa). The Group 1 samples gave a flexural strength of 101.45 ± 3.13 MPa, and Group 2 gave the lowest flexural strength (85.98 ± 3.49 MPa) among the four groups tested. CONCLUSION: The reduction in flexural strength of the heat-activated PMMA denture base after adding 0.2% by weight of AgNP as an antifungal agent was a major concern among manufacturers of commercially available denture base materials. It was proved in the present study that employing the autoclave curing method of terminal boiling for the polymerization of 0.2% by weight of AgNp-added heat-activated PMMA denture base resulted in a significantly higher flexural strength compared to the conventional curing method of terminal boiling for polymerization. Unmodified heat-activated PMMA gave higher flexural strength values when polymerized by autoclave curing compared to the conventional curing method of terminal boiling.

Extracellular Matrix Mimicking Wound Microenvironment Responsive Amyloid-Heparin@TAAgNP Co-Assembled Hydrogel: An Effective Conductive Antibacterial Wound Healing Material.

Bioengineered composite hydrogel platforms made of a supramolecular coassembly have recently garnered significant attention as promising biomaterial-based healthcare therapeutics. The mechanical durability of amyloids, in conjunction with the structured charged framework rendered by biologically abundant key ECM component glycosaminoglycan, enables us to design minimalistic customized biomaterial suited for stimuli responsive therapy. In this study, by harnessing the heparin sulfate-binding aptitude of amyloid fibrils, we have constructed a pH-responsive extracellular matrix (ECM) mimicking hydrogel matrix. This effective biocompatible platform comprising heparin sulfate-amyloid coassembled hydrogel embedded with polyphenol functionalized silver nanoparticles not only provide a native skin ECM-like conductive environment but also provide wound-microenvironment responsive on-demand superior antibacterial efficacy for effective diabetic wound healing. Interestingly, both the cytocompatibility and antibacterial properties of this bioinspired matrix can be fine-tuned by controlling the mutual ratio of heparin sulfate-amyloid and incubated silver nanoparticle components, respectively. The designed biomaterial platform exhibits notable effectiveness in the treatment of chronic hyperglycemic wounds infected with multidrug-resistant bacteria, because of the integration of pH-responsive release characteristics of the incubated functionalized AgNP and the antibacterial amyloid fibrils. In addition to this, the aforementioned assemblage shows exceptional hemocompatibility with significant antibiofilm and antioxidant characteristics. Histological evidence of the incised skin tissue sections indicates that the fabricated composite hydrogel is also effective in controlling pro-inflammatory cytokines such as IL6 and TNFα expressions at the wound vicinity with significant upregulation of angiogenesis markers like CD31 and α-SMA.