The influence of Ag2O/NbO2 nanocomposites on the optical properties of PVA/PVP lend in biomedical applications.

OBJECTIVE: To study the optical properties of nanocomposites as well as antibacterial activity. METHODS: The experimental study was conducted at the University of Babylon, College of Science and College of Education for Pure Sciences, Babylon, Iraq, from September 2021 to February 2022. Impregnation of transparent matrix polyvinyl alcohol and polyvinyl pyrrolidone nanocomposites was done by silver oxide and niobium oxide nanoparticles. The nanostructures were created using different ratios of polymer matrix, silver oxide nanoparticles and niobium oxide nanoparticles. The optical features of these nanocomposites were examined, whereby the latter type of properties was tested within the wavelength range of 220-820nm. The determination of the anti-microbial activity was done by disc diffusion method. The anti-bacterial activity involved gram-positive and gram-negative organisms. Different bacteria were cultured with Muller-Hinton medium. RESULTS: Absorbance, absorption coefficients and optical conductivity of the nanocomposites increased with the increase in nanocomposite concentrations. The energy gap for silver oxide and niobium oxide nanoparticles decreased when the concentrations of the nanoparticles increased. CONCLUSIONS: Promising outcomes may be achieved for the nanocomposites in anti-bacterial applications as the inhibition zones increased along with increased ratio of silver oxide and niobium oxide nanoparticles.

Antibacterial and Antitumoral Potentials of Phytosynthesized Silver/Silver Oxide Nanoparticles Using Tomato Flower Waste.

This study presents the phytosynthesis of silver-based nanoparticles using tomato flower waste extracts for the first time in the literature. The determination of total polyphenolic and flavonoid contents in the extracts showed high gallic acid equivalents (6436-8802 mg GAE/kg dm) and high quercetin equivalents (378-633 mg QE/kg dm), respectively, dependent on the extraction method. By the Ultra Performance Liquid Chromatography technique, 14 polyphenolic compounds were identified and quantified in the tomato flower waste extracts. The abundant phenolic compounds were caffeic acid (36,902-32,217 mg/kg) and chlorogenic acid (1640-1728 mg/kg), and the abundant flavonoid compounds were catechin (292-251 mg/kg) and luteolin (246-108 mg/kg). Transmission electron microscopy of the nanoparticles revealed a particle size range of 14-40 nm. Fourier Transform infrared spectroscopy and X-ray diffraction studies confirmed the phytosynthesis of the silver/silver oxide nanoparticles. These findings hold significant results for the antibacterial and antitumoral potential applications of the obtained nanoparticles, opening new areas for research and development and inspiring further exploration. The impact of this research on the field of metallic nanoparticle phytosynthesis is substantial, as it introduces a novel approach and could lead to significant advancements in the field.

Efficacy of silver diamine fluoride (SDF) in arresting dentin caries against inter-kingdom biofilms of Streptococcus mutans and Candida albicans.

OBJECTIVES: To compare, in vitro, the efficacy of three proprietary silver diamine fluoride (SDF) products in mitigating progression of dentinal caries induced by an inter-kingdom, dual-species, bacterial-yeast biofilm. METHODS: Human dentin blocks were demineralized to create artificial caries lesions and randomized into three SDF test groups: Saforide, Topamine, T-SDF, and an aqueous control (n = 26 per group). After application of foregoing SDF variants, the blocks were incubated with Streptococcus mutans and Candida albicans for 24 h for biofilm development, and subsequently subjected to a microbe-induced, pH-cycling process for 7 days, to mimic the oral eco-system. The biofilm cell viability and surface topography were assessed by colony-forming units (CFUs) and scanning electron microscopy respectively. The lesion depth and mineral density were evaluated by micro-computer tomography. SDF precipitate and matrix-to-mineral ratio were evaluated by X-ray diffraction and Fourier transform infrared spectroscopy, respectively. Standard, accepted methodology was used for all these evaluations and procedures. RESULTS: After pH cycling, the SDF groups demonstrated comparable inhibition of the biofilm relative to the control. the log CFU of S. mutans for Saforide, Topamine, T-SDF, and control were 6.69±0.73, 6.48±0.56, 6.63±0.66, and 8.01±0.45, respectively. For C. albicans, the log CFU were 4.86±0.44, 4.72±0.53, 4.92±0.29, and 5.60±0.27, respectively. The log CFU of S. mutans and C. albicans in the SDF groups were significantly lower than the control group (p<0.001). Further, the lesion depth decreased by approximately 14.79±7.00% in the SDF groups, while it increased by 11.07±8.61% in the control (p<0.001), and the mineral density increased by 16.36±4.58% in the SDF group, as opposed to a 5.59±2.64% reduction in the control (p<0.001) implying their caries mitigating effect. These findings were corroborated by SEM images of the lesions. CONCLUSION: SDF significantly mitigated dentin caries due to an assault by a polymicrobial plaque biofilm whilst arresting mineral loss and lesion growth. There was no difference in the caries-arresting efficacy of the compared SDF variants.

Harnessing the power of Neobacillus niacini AUMC-B524 for silver oxide nanoparticle synthesis: optimization, characterization, and bioactivity exploration.

BACKGROUND: Biotechnology provides a cost-effective way to produce nanomaterials such as silver oxide nanoparticles (Ag2ONPs), which have emerged as versatile entities with diverse applications. This study investigated the ability of endophytic bacteria to biosynthesize Ag2ONPs. RESULTS: A novel endophytic bacterial strain, Neobacillus niacini AUMC-B524, was isolated from Lycium shawii Roem. & Schult leaves and used to synthesize Ag2ONPS extracellularly. Plackett-Burman design and response surface approach was carried out to optimize the biosynthesis of Ag2ONPs (Bio-Ag2ONPs). Comprehensive characterization techniques, including UV-vis spectral analysis, Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, dynamic light scattering analysis, Raman microscopy, and energy dispersive X-ray analysis, confirmed the precise composition of the Ag2ONPS. Bio-Ag2ONPs were effective against multidrug-resistant wound pathogens, with minimum inhibitory concentrations (1-25 µg mL-1). Notably, Bio-Ag2ONPs demonstrated no cytotoxic effects on human skin fibroblasts (HSF) in vitro, while effectively suppressing the proliferation of human epidermoid skin carcinoma (A-431) cells, inducing apoptosis and modulating the key apoptotic genes including Bcl-2 associated X protein (Bax), B-cell lymphoma 2 (Bcl-2), Caspase-3 (Cas-3), and guardian of the genome (P53). CONCLUSIONS: These findings highlight the therapeutic potential of Bio-Ag2ONPs synthesized by endophytic N. niacini AUMC-B524, underscoring their antibacterial efficacy, anticancer activity, and biocompatibility, paving the way for novel therapeutic strategies.

Effects of light curing on silver diamine fluoride-treated carious lesions: A systematic review.

OBJECTIVE: This systematic review aims to evaluate the potential benefits and underlying mechanisms of combining SDF with light curing, based on available studies. MATERIALS AND METHODS: A systematic search of publications was conducted with the keywords "silver diamine fluoride" or "silver fluoride" and "dental light curing," "LED curing," "dental laser," and "dental polymerization" in 4 databases: PubMed, EBSCO, Scopus, and Google Scholar to identify English-language articles published up to March 2023. Duplicate publications were deleted. Two reviewers screened the titles and abstracts and excluded irrelevant publications. The full text of the remaining publications was retrieved. Studies investigating the effect of light-curing on SDF-treated carious lesions were included. RESULTS: The 175 publications initially found included 5 laboratory studies investigating the effects of light curing on 38% SDF-treated dentine carious lesions, but no clinical study was found. Four of these studies were conducted on extracted primary teeth, and one was on extracted permanent teeth. SDF with light curing increased microhardness (n = 3, p < .05) showed a higher mineral density (n = 1, p < .041) and had more silver ion precipitation in infected dentine (n = 1, p < .016) compared to SDF without light curing. Moreover, no significant differences in the antibacterial activity were observed between SDF with light curing and SDF alone (n = 1, p > .05). CONCLUSION: Drawing from the limited number of laboratory studies, incorporating light curing subsequent to the SDF application yields potential favorable outcomes that include augmented microhardness, elevated mineral density, and heightened silver ion precipitation within infected dentine. Future clinical research is required to confirm or refute the benefit of light curing on SDF-treated carious lesions.

Remineralizing effect of NSF on artificial enamel caries.

INTRODUCTION: Nanotechnology offers new approaches and endless opportunities for remineralizing tooth decay without being toxic or causing allergies. This study aimed to determine the effect of nanosilver fluoride (NSF) on the remineralization potential of enamel caries-like lesions compared to 5% sodium fluoride varnish in permanent teeth. METHODS: Fifteen teeth (molars and premolars) were gathered, cleaned, and polished using a scaler. After sectioning the teeth mesiodistally and removing the roots, the thirty specimens were subjected to a demineralized solution to induce early enamel lesions and then assigned randomly into two equal groups. The test materials were applied, and then all the specimens were subjected to a pH cycling model for 30 days. DIAGNOdent and surface roughness were investigated, and an evaluation of the enamel Ca and P weight% for Ca/P ratio calculation was done using SEM-EDX to analyze the specimens at the end of the study. The data were analyzed using an independent t-test. RESULTS: The mean values for the DIAGNOdent measurements for NSF and NaF at baseline and after demineralization were not significantly different (p > 0.05). After treatment, NaF varnish showed a significantly higher mean DIAGNOdent measurement (11.8 ± 5.80) than NSF (4.7 ± 1.6). The mean surface roughness of the NaF group (1.64 ± 0.39) was much higher than NSF's mean surface roughness (1.07 ± 0.21). Specimens treated with NSF had statistically significant smoother surfaces (p < 0.001). The NSF group had a higher mean Ca/P ratio (2.9 ± 0.35) than NaF (2.2 ± 0.11). This difference was statistically significant (p = 0.012). CONCLUSION: The study reveals that nano silver fluoride is a more effective treatment than sodium fluoride varnish in enhancing teeth's clinical characteristics, particularly in terms of mineral content and surface roughness, suggesting it could be an improved strategy to prevent dental caries and maintain enamel integrity.

Synthesis and analysis of multifunctional graphene oxide/Ag2O-PVA/chitosan hybrid polymeric composite for wound healing applications.

The requirement for accurate treatments for skin diseases and wounds, generated a rising interest towards multifunctional polymer composites, that are capable of mimicking the natural compositions in human body. Also, electroactive composite films disseminate endogenous electrical stimulations that encourage cell migration and its proliferation at wound site, proposing greater opportunities in upgrading the conventional wound patches. In this work, the composite film made of graphene oxide, Ag2O, PVA and chitosan were developed for wound healing applications, by the solution casting method. The even dispersibility of nanofiller in polymeric matrix was validated from the physicochemical analyses. The increment in roughness of the composite film surface was noted from AFM images. The thermal stability and porous nature of the polymer composite were also verified. A conductivity value of 0.16 × 10-4 Scm-1 was obtained for the film. From MTT assay, it was noted that the films were non-cytotoxic and supported cell adhesion along with cell proliferation of macrophage (RAW 264.7) cells. Moreover, the composite film also demonstrated non-hemolytic activity of <2 %, as well as excellent antibacterial activity towards E. coli and S. aureus. Thus, the obtained results validated that the prepared composite film could be chosen as an innovative candidate for developing state-of-the-art wound dressings.

Immobilized Drugs on Dual-Mode Imaging Ag2S/BaSO4/PVA Embolic Microspheres for Precise Localization, Rapid Embolization, and Local Antitumor Therapy.

Transcatheter arterial embolization (TAE) in interventional therapy and tumor embolism therapy plays a significant role. The choice of embolic materials that have good biocompatibility is an essential component of TAE. For this study, we produced a multifunctional PVA embolization material that can simultaneously encapsulate Ag2S quantum dots (Ag2S QDs) and BaSO4 nanoparticles (BaSO4 NPs), exhibiting excellent second near-infrared window (NIR-II) fluorescence imaging and X-ray imaging, breaking through the limitations of traditional embolic microsphere X-ray imaging. To improve the therapeutic effectiveness against tumors, we doped the doxorubicin (DOX) antitumor drug into microspheres and combined it with a clotting peptide (RADA16-I) on the surface of microspheres. Thus, it not only embolizes rapidly during hemostasis but also continues to release and accelerate tumor necrosis. In addition, Ag2S/BaSO4/PVA microspheres (Ag2S/BaSO4/PVA Ms) exhibited good blood compatibility and biocompatibility, and the results of embolization experiments on renal arteries in rabbits revealed good embolic effects and bimodal imaging stability. Therefore, they could serve as a promising medication delivery embolic system and an efficient biomaterial for arterial embolization. Our research work achieves the applicability of NIR-II and X-ray dual-mode images for clinical embolization in biomedical imaging.

Drug delivery and antibiofilm efficacy of nano silver fluoride sustained release orthodontic elastomerics against Streptococcus mutans.

We aimed to investigate the chemical and physical properties of nano silver fluoride sustained release orthodontic elastomerics (NSF-RE) and determine their antimicrobial and antibiofilm formation activities against Streptococcus mutans. Orthodontic elastomerics were dip-coated with NSF solution in ethyl cellulose (EC) and polyethylene glycol 6000 (PEG). The studied groups included NSF (no EC/PEG), NSF-E (EC), NSF-EP1 (EC:PEG, 4:1), and NSF-EP2 (EC:PEG, 2:1). The cumulative release of silver nanoparticles (AgNPs) and fluoride, along with the compatibility of the tensile force with orthodontic brackets, was evaluated. The antimicrobial activity was evaluated using an agar diffusion test. The inhibition of biofilm formation was evaluated using colony-forming units (CFUs), biofilm thickness, and the live/dead cell ratio. NSF-RE containing EC sustained the release of AgNPs and fluoride for > 7 days. Tensile forces were not significantly different among the groups. The inhibition zone was 2.64- and 1.31-fold larger with NSF-EP2 than that with NSF and NSF-E, respectively. NSF-EP2 was the most effective in inhibiting biofilm formation with significant reductions in CFUs, biofilm thickness, and live/dead cell ratio by 57, 86, and 96%, respectively, as compared to those in the control group. Overall, sustained release of AgNPs and fluoride by NSF-RE provides antimicrobial and antibiofilm effects against S. mutans.

Analysis of therapeutic effect of silver-based dressings on chronic wound healing.

Chronic wounds are susceptible to bacterial infections and at high risk of developing antibiotic-resistant bacterial infections. Silver is an antimicrobial by targeting almost all types of bacteria in chronic wounds to reduce the bacterial load in the infected area and further facilitate the healing process. This study focused on exploring whether silver-based dressings were superior to non-silver dressings in the treatment of chronic wounds. PubMed, Web of Science and Embase were comprehensively searched from inception to March 2024 for randomized clinical trials and observational studies. The endpoints in terms of wound healing rate, complete healing time, reduction on wound surface area and wound infection rate were analysed using Review Manager 5.4 software. A total of 15 studies involving 5046 patients were eventually included. The results showed that compared with patients provided with non-silver dressings, patients provided with silver-based dressings had higher wound healing rate (OR: 1.43, 95% CI: 1.10-1.85, p = 0.008), shorter complete healing time (MD: -0.96, 95% CI: -1.08 ~ -0.85, p < 0.00001) and lower wound infection rate (OR: 0.56, 95% CI: 0.40-0.79, p = 0.001); no significant difference in the reduction on wound surface area (MD: 12.41, 95% CI: -19.59-44.40, p = 0.45) was found. These findings suggested that the silver-based dressings were able to enhance chronic wound healing rate, shorten the complete healing time and reduce wound infection rate, but had no significant improvement in the reduction on wound surface area. Large-scale and rigorous studies are required to confirm the beneficial effects of silver-based dressings on chronic wound healing.

Preventing proximal enamel caries in neighboring tooth with glass ionomer cement restoration and silver diamine fluoride pretreatment.

OBJECTIVE: To investigate caries preventive effects of 38 % silver diamine fluoride (SDF) pretreatment on neighboring tooth proximal to glass ionomer cement (GIC), including conventional GIC (CGIC) and resin-modified GIC (RMGIC) restorations in an in vitro model. METHODS: HUMAN TOOTH BLOCKS WERE RESTORED WITH: SDF+CGIC (Group 1), CGIC (Group 2), SDF+RMGIC (Group 3) or RMGIC (Group 4). Enamel specimen simulating proximal surface of neighboring tooth was placed in proximity to the restorations. The specimen underwent cariogenic challenge with cross-kingdom biofilm of Streptococcus mutans, Lacticaseibacillus casei and Candida albicans. After cariogenic challenge, the biofilm's growth kinetics, viability, and morphology were evaluated by propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), respectively. The enamel lesion depth, surface morphology and crystal characteristics were determined by micro-computed tomography (micro-CT), SEM and X-ray diffraction (XRD), respectively. RESULTS: PMA-qPCR demonstrated lower microbial growth in Group 1 and 3 compared with Group 2 and 4 (p < 0.05). CLSM showed the dead-to-live ratio in Groups 1-4 were 1.15±0.12, 0.53±0.13, 1.10±0.24 and 0.63±0.10, respectively (Group 1,3 > 2,4, p < 0.05). SEM revealed Groups 1 and 3 had scattered biofilm whereas Group 2 and 4 had confluent biofilm. Micro-CT showed the enamel lesion depths (µm) were 98±9, 126±7, 103±6 and 128±7 for Group 1 to 4, respectively (Group 1,3 < 2,4, p < 0.05). SEM revealed oriented and ordered enamel prismatic patterns in Group 1 and 3, not in Group 2 and 4. XRD showed the reflections of hydroxyapatite in Groups 1 and 3 were sharper than Groups 2 and 4. CONCLUSION: SDF pretreatment enhances the preventive effect of GIC on proximal enamel surface on neighboring tooth through inhibiting cariogenic biofilm, reducing enamel demineralization and promoting enamel remineralization. CLINICAL SIGNIFICANCE: SDF pretreatment of GIC restorations can help prevent caries on neighboring teeth, particular for patients with high caries risk.

Developing a novel antibacterial copper tetraamine fluoride.

OBJECTIVE: To develop a novel and biocompatible copper tetraamine fluoride (CTF) with antibacterial and nondiscolouring properties. METHOD: This study used copper fluoride and ammonia solution to develop CTF solution. The CTF was characterized by X-ray photoelectron spectroscopy (XPS). Cytotoxicity was evaluated by stem cells from human exfoliated deciduous teeth (SHED) and human gingival fibroblasts (HGF-1). The fluoride concentration was determined using ion-selective electrode. The alkalinity was measured by a pH electrode. The human dentine blocks were treated with CTF and then incubated with Streptococcus mutans to evaluate the antimicrobial and discolouring effects. The silver diamine fluoride (SDF) was employed as the positive control, and water was the negative control. The colony-forming units (CFUs) and confocal laser scanning microscopy (CLSM) were used to examine the kinetics and viability of the biofilm. The discolouring property on dentine was assessed by spectrophotometry. One-way analysis of variance with the Bonferroni post hoc test was performed to assess and compare the data. RESULTS: XPS confirmed synthesis of CTF solution. The half-maximal inhibitory concentration of CTF on SHED and HGF-1 was 195±16 ppm and 137±11 ppm. The fluoride concentration was 121,000±5,000 ppm. The pH value was 9. Log10 CFU of the CTF, SDF and water group were 5.0 ± 0.2, 4.9 ± 0.1 and 7.4 ± 0.1 (p < 0.001, CTF, SDFWater). Spectrophotometry showed that the ΔE of the CTF, SDF and water group were 5 ± 2, 6 ± 3 and 45±2 (p < 0.001, CTF, Water

Rough Ag2S@H-CeO2 photonic nanocomposites for effective eradication of drug-resistant bacteria and improved healing of infected cutaneous wounds.

With the continuous increasing threat of drug-resistant bacteria induced cutaneous wound infections, there is a growing demand for novel effective antibiotics-alternative antibacterial strategies for clinical anti-infective therapy. Here, we report the fabrication and antibacterial efficacy of Ag2S@H-CeO2 photonic nanocomposites with rough surface through in-situ growth of Ag2S nanoparticles on CeO2 hollow spheres. With excellent photothermal property and peroxidase-like activity, as well as increased bacterial adhesion, the photonic nanocomposites demonstrated a broad-spectrum synergistic antibacterial effect against Gram-positive, Gram-positive bacteria and fungi as well biofilm in vitro. Significantly, the nanocomposites can effectively eradicate drug-resistant bacteria such as Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL E. coli). Notably, in vivo assessments validated its synergistic therapeutic potential in the treatment of MRSA-infected cutaneous wounds, all while maintaining excellent biosafety and biocompatibility. Our study offers a competitive and promising strategy for the development of a multifunctional synergistic antibacterial platform poised to effectively treat drug-resistant bacteria-infected cutaneous wounds.

Amino Acid-Conjugated Polymer-Silver Bromide Nanocomposites for Eradicating Polymicrobial Biofilms and Treating Burn Wound Infections.

The rise in antimicrobial resistance, the increasing occurrence of bacterial, and fungal infections, and the challenges posed by polymicrobial biofilms necessitate the exploration of innovative therapeutic strategies. Silver-based antimicrobials have garnered attention for their broad-spectrum activity and multimodal mechanisms of action. However, their effectiveness against single-species or polymicrobial biofilms remains limited. In this study, we present the fabrication of polymer-silver bromide nanocomposites using amino acid conjugated polymers (ACPs) through a green and water-based in situ technique. The nanocomposite architecture facilitated prolonged and controlled release of the active components. Remarkably, the nanocomposites exhibited broad-spectrum activity against multidrug-resistant (MDR) human pathogenic bacteria (MIC = 2-16 µg/mL) and fungi (MIC = 1-8 µg/mL), while displaying no detectable toxicity to human erythrocytes (HC50 > 1024 µg/mL). In contrast to existing antimicrobials and silver-based therapies, the nanocomposite effectively eradicated bacterial, fungal, and polymicrobial biofilms, and prevented the development of microbial resistance due to their membrane-active properties. Furthermore, the lead polymer-silver bromide nanocomposite demonstrated a 99% reduction in the drug-resistant Pseudomonas aeruginosa burden in a murine model of burn wound infection, along with excellent in vivo biocompatibility.

Structural engineering of mitochondria-targeted Au-Ag2S photosensitizers for enhanced photodynamic and photothermal therapy.

Much effort has been devoted to designing diverse photosensitizers for efficient photodynamic therapy (PDT) and photothermal therapy (PTT) performance. However, the effect of PS morphology on the PDT and PTT performance needs to be further explored. In this work, a photosensitizer, Au-Ag2S nanoparticles functionalized with indocyanine green, caspase-3 recognition peptides, and mitochondria-targeting peptides (AICM NPs) with different morphologies, including core-shell, eccentric core-shell-I, eccentric core-shell-II, and Janus morphologies, were synthesized to enhance PDT and PTT performance. Among them, AICM Janus NPs with enhanced charge-transfer efficiency and photothermal conversion demonstrate superior PDT and PTT performance compared to those of other morphologies. In addition, AICM NPs exhibit satisfactory surface-enhanced Raman scattering performance for in situ SERS monitoring of caspase-3 during PDT and PTT processes. After PDT and PTT treatment with AICM Janus NPs, the damaged mitochondria released caspase-3. AICM Janus NPs achieved a superior apoptosis rate in tumor cells in vitro. Furthermore, AICM Janus NPs treat the tumors in vivo within only 10 days, which is half the time reported in other work. The AICM NPs demonstrated superior therapeutic safety both in vitro and in vivo. This study investigates the effects of morphology-property-performance of photosensitizers on the PDT and PTT performances, which opens a new pathway toward designing photosensitizers for efficient PDT and PTT.

Electrospun high hydrophilicity antimicrobial poly (lactic acid)/silk fibroin nanofiber membrane for wound dressings.

Antimicrobial wound dressings can aid wound healing by preventing bacterial infection. This is particularly true of electrospun ones, which have a porous structure and can be easily loaded with antimicrobial drugs. Here, Poly lactic acid (PLA), Silk Fibroin (SF) and antimicrobial agents of Silver nanoparticles (Ag NPs) and Silver oxide (Ag2O) to prepare the PLA/SF composites antimicrobial nanofiber membrane by electrospinning. The PLA with 30 % SF nanofiber membrane show the water vapor permeability (WVP) and the liquid absorption of 36 g·mm/(m2·d·kPa) and 1721 %. With the increasing of SF contents, the degradation rate and surface hydrophilicity of the nanofiber membrane increase significantly. The nanofiber membrane exhibited excellent antimicrobial activity against Pseudomonas aeruginosa (P. aeruginosa) with the inhibition circle reach at 18.2 mm. The resultant nanofiber membrane showed high cytosolic activity, good cytocompatibility and strong antimicrobial ability, which laid a theoretical foundation for the construction of a new PLA/SF composites antimicrobial fiber membrane.

Silver peroxide-incorporated carbon dots with high photothermal performance for combating bacteria.

The widespread use of antibiotics often increases bacterial resistance. Herein, we reported a silver peroxide-incorporated carbon dots (defined as Ag2O2-CDs) with high photothermal conversion efficiency viain situoxidation process. The prepared Ag2O2-CDs exhibited ultra-small size of 2.0 nm and hybrid phase structure. Meanwhile, the Ag2O2-CDs were of a similar optical performance comparing with traditional carbon dots (CDs). Importantly, the incorporation of Ag2O2into CDs significantly enhanced photothermal conversion efficiency from 3.8% to 28.5%. By combining silver ion toxicity and photothermal ablation, the Ag2O2-CDs were capable of destroying gram-positive and gram-negative bacterium effectively. These findings demonstrated that the Ag2O2-CDs could be served as a potential antibacterial agent for clinical applications.

Effect of silver diamine fluoride combined with photodynamic therapy on primary enamel microhardness.

OBJECTIVES: This study aimed to assess the effect of silver diamine fluoride (SDF) combined with photodynamic therapy (PDT) on primary enamel microhardness. MATERIALS AND METHODS: This in vitro, experimental study was conducted on 40 extracted primary molars with sound buccal/lingual surfaces. The baseline enamel microhardness of the teeth was initially measured by a Vickers hardness tester. Next, the teeth were randomly assigned to four groups (n = 10) for treatment with SDF, PDT, SDF plus PDT, and control (no intervention). After the intervention, the teeth underwent a 14-day pH-cycling, and enamel microhardness was measured again. The change in microhardness was calculated for each group, and comparisons were made by two-way ANOVA and t-test (alpha = 0.05). RESULTS: The mean secondary microhardness of the three intervention groups was significantly higher than that of the control group (P<0.05). Despite slightly higher microhardness in SDF + PDT group, followed by the SDF group, the difference in secondary microhardness was not significant among the three intervention groups (P>0.05). CONCLUSION: Treatment of primary enamel with SDF or PDT can increase its microhardness and enhance remineralization. However, combined use of SDF and PDT had no additional advantage over the use of SDF alone.

Antibacterial and antibiofilm efficacy of Solanum lasiocarpum root extract synthesized silver/silver chloride nanoparticles against Staphylococcus haemolyticus associated with bovine mastitis.

Staphylococcus haemolyticus is a cause of bovine mastitis, leading to inflammation in the mammary gland. This bacterial infection adversely affects animal health, reducing milk quality and yield. Its emergence has been widely reported, representing a significant economic loss for dairy farms. Interestingly, S. haemolyticus exhibits higher levels of antimicrobial resistance than other coagulase-negative Staphylococci. In this study, we synthesized silver/silver chloride nanoparticles (Ag/AgCl-NPs) using Solanum lasiocarpum root extract and evaluated their antibacterial and antibiofilm activities against S. haemolyticus. The formation of the Ag/AgCl-NPs was confirmed using UV-visible spectroscopy, which revealed maximum absorption at 419 nm. X-ray diffraction (XRD) analysis demonstrated the crystalline nature of the Ag/AgCl-NPs, exhibiting a face-centered cubic lattice. Fourier transform infrared (FT-IR) spectroscopy elucidated the functional groups potentially involved in the Ag/AgCl-NPs synthesis. Transmission electron microscopy (TEM) analysis revealed that the average particle size of the Ag/AgCl-NPs was 10 nm. Antimicrobial activity results indicated that the minimum inhibitory concentration (MIC) and maximum bactericidal concentration (MBC) of the Ag/AgCl-NPs treatment were 7.82-15.63 µg/mL towards S. haemolyticus. Morphological changes in bacterial cells treated with the Ag/AgCl-NPs were observed under scanning electron microscopy (SEM). The Ag/AgCl-NPs reduced both the biomass of biofilm formation and preformed biofilm by approximately 20.24-94.66 % and 13.67-88.48 %. Bacterial viability within biofilm formation and preformed biofilm was reduced by approximately 21.56-77.54 % and 18.9-71.48 %, respectively. This study provides evidence of the potential of the synthesized Ag/AgCl-NPs as an antibacterial and antibiofilm agent against S. haemolyticus.

Antiviral Activity of Ag5IO6, a Unique Silver Compound.

Pentasilver hexaoxoiodate (Ag5IO6) has broad-spectrum antimicrobial efficacy, including the long-term prevention of microbial adherence, the rapid killing of planktonic microorganisms, and the elimination of mature biofilms. This study's goal was to determine whether it may also have antiviral activity against structurally distinct viruses. Ag5IO6 was tested following ASTM E1052-20, Standard Practice to Assess the Activity of Microbicides Against Viruses in Suspension, against adenovirus type 5, murine norovirus, poliovirus type 1, SARS-CoV-2 (original), and SARS-CoV-2 (omicron) (host cells: H1HeLa, RAW 264.7, LLC-MK2, Vero E6, and Vero E6, respectively). A 0.1 g/mL Ag5IO6 suspension was prepared and the viruses were exposed for 30 min, 4 h, or 24 h. Exposure to Ag5IO6 resulted in complete kill of SARS-CoV-2 (omicron) within 30 min, as well as complete kill of both SARS-CoV-2 (original) and the murine norovirus within 4 h. Ag5IO6 showed increasing activity over time against the adenovirus, but did not achieve a 3-log reduction within 24 h, and showed no antiviral activity against the poliovirus. These results demonstrate that Ag5IO6 has antiviral activity against medically important viruses, in addition to its well-characterized antimicrobial activity, suggesting that it may be valuable in situations where the prevention or simultaneous treatment of microbes and viruses are necessary.