Photoresponsive Hydrogel Dressing Containing Nanoparticles with Excellent Synergetic Photodynamic, Photothermal, and Chemodynamic Therapies for Effective Infected Wound Healing.

Bacterial resistance to antibiotics can negatively affect the treatment of infected skin wounds. The combination of synergistic antibacterial therapies with photodynamic, photothermal, and chemodynamic therapies has been recognized as one of the most promising approaches. In this study, we have developed MSN@Ce6@MnO2-CS/Ag (MCMA) nanoparticles to serve as powerful antibacterial agents when exposed to both 660 nm visible light and 808 nm near-infrared (NIR) light. Through dual-light irradiation, MCMA can induce hyperthermia and generate reactive oxygen species (ROS), leading to a remarkable enhancement in photothermal antibacterial effects and accelerating wound healing. It has a peroxidase-like catalytic activity and promotes the generation of hydroxyl radicals (·OH) by catalyzing the decomposition of H2O2. In vitro antibacterial experiments demonstrated the excellent antibacterial activity of MCMA. The antibacterial efficacy of MCMA at a concentration of 250 µg ml-1 was found to be 99.6 and 100% toward Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, respectively, under irradiation with an 808 and 660 nm laser. The results of the animal experiments demonstrated that MCMA can effectively accelerate wound healing through wound ulceration inhabitation. These findings substantiate the assertion that synthetic MCMA represents an efficacious strategy for bacterial inhibition and wound healing.

Comparative Evaluation of the Mechanical Efficiency of Nanosilver Fluoride and Sodium Fluoride Varnish: An In Vitro Study.

Background: Dental caries is the most common disease in childhood and has an impact on general health status. The topical application of fluoride varnishes has been used for the prevention and control of dental caries due to their high fluoride content, adhesion capacity, and safety. Silver has a varied application in medicine as well as in dentistry due to its anticaries, antimicrobial, and antirheumatic potentials. The introduction of nanosilver fluoride (NSF) was made with advancements in technology to overcome the drawbacks of silver diamine fluoride (SDF). Aim: To compare and evaluate the microhardness and microleakage of NSF varnish and sodium fluoride (NaF) varnish. Materials and methods: An in vitro comparative experimental study was carried out between synthesized NSF and commercially available NaF, with 20 samples in each group. The specimens were sectioned and subjected to microhardness evaluation using Vickers microhardness testing and the dye penetration method to evaluate the microleakage. Results: The average microhardness was found to be 230.7218 VMH for NSF (group I), 198.9841 VMH for NaF (group II), and 91.6120 VMH for group III. These differences were statistically significant when compared with each other (p = 0.002). In 50% of the samples, no dye penetration was seen in the NSF group, compared to the NaF varnish group, where 75% of the samples exhibited penetration onto the varnish interface or the varnish and tooth interface. Conclusion: Nanosilver fluoride proves to be an effective alternative to commercially available topical fluoride agents such as NaF. It has greater microhardness and lower microleakage than NaF and the control teeth. Clinical significance: Nanosilver fluoride varnish can be used as a cost-effective alternative to NaF varnish and SDF. It can be applied with minimal training by healthcare workers or general practitioners. How to cite this article: Kritivasan S, Sogi HS, Jain M, et al. Comparative Evaluation of the Mechanical Efficiency of Nanosilver Fluoride and Sodium Fluoride Varnish: An In Vitro Study. Int J Clin Pediatr Dent 2024;17(5):539-544.

Assessment of Nanosilver Fluoride Application on the Microtensile Bond Strength of Glass Ionomer Cement and Resin-modified Glass Ionomer Cement on Primary Carious Dentin: An In Vitro Study.

Background and objectives: Nanosilver sodium fluoride (NSF) has recently gained popularity in dentistry as an alternative to silver diamine fluoride (SDF) due to its drawbacks of staining the tooth black and possibly causing soft tissue injury, which has been eliminated in NSF due to the nanoparticle size of silver. This study aims to assess the microtensile bond strength of glass ionomer cement (GIC) and resin-modified glass ionomer cement (RMGIC) with pretreatment of NSF on extracted primary carious teeth. Materials and methods: Teeth were stored in 10% formalin. The roots were severed, and the pulp chambers were cleaned. The occlusal enamel was ground, reducing the dentin thickness by 1 mm. The specimens were covered with nail varnish, leaving only the area of flat dentin exposed. Caries were induced microbiologically by inoculating Streptococcus mutans. Group I-NSF with GIC restoration, group II-NSF with RMGIC restoration, group III-restoration with GIC, and group IV-restoration with RMGIC. After different surface treatments of the carious dentin were performed, each specimen was placed in the testing jig of a universal testing machine and stressed in tension at a crosshead speed of 1 mm/minute until bond failure was observed. They were air-dried and placed under a scanning electron microscope. The failure modes-adhesive, cohesive, and mixed failure were recorded for statistical evaluation. Results: Maximum results of microtensile bond strength were seen in the pretreatment group with NSF sealant, followed by RMGIC restoration, and the least results were observed in the conventional GIC restoration group. Of all the types of failures in our study, adhesive was the maximum type. Interpretation and conclusion: The microtensile bond strength of pretreatment with NSF showed higher values when compared to conventional restorations of GIC and RMGIC. The failure modes in each group were not significantly varied. Pretreatment with NSF will prevent secondary caries formation, and the restorations will also be stronger. How to cite this article: Das A, Ramamurthy N, Srinivasan I, et al. Assessment of Nanosilver Fluoride Application on the Microtensile Bond Strength of Glass Ionomer Cement and Resin-modified Glass Ionomer Cement on Primary Carious Dentin: An In Vitro Study. Int J Clin Pediatr Dent 2024;17(5):565-569.

A rapid microwave approach for 'one-pot' synthesis of antibiotic conjugated silver nanoparticles with antimicrobial activity against multi-drug resistant bacterial pathogens.

Deaths directly attributable to drug-resistant infections reached 1.27 million in 2019 and continue to rise. This escalating resistance to antibiotics has driven a resurgence in the exploration of ancient antimicrobials to develop efficacious alternatives. The modern field of nanomaterials is a promising area of research with silver nanoparticles performing well as antimicrobial agents due to their large surface area and multiple bacterial targets. In the current study antibiotic conjugated silver nanoparticles (3-35 nm) were synthesized using ß-lactam antibiotic, ampicillin. The method of heating during synthesis either microwave (4 min) or convection (4 h) influenced the physical characteristics of the ampicillin coated silver nanoparticles, however both approaches produced nanomaterials with antimicrobial activity against a variety of multi-drug resistant (MDR) clinical isolates in physiologically relevant media (when present at <0.2-2.28 mg L-1 in defined media). Critically, the microwave method is five times faster than the traditional water bath method, allowing rapid synthesis of ampicillin-conjugated nanoparticles, which supports scale up processes for industry. We suggest that the combination of antibiotic and silver in these nanoparticles produces a synergistic effect that circumvents resistance mechanisms and has the potential to provide a new line of combinatorial agents able to treat multi-drug resistant infections.

Comparative Evaluation of Antimicrobial Activity and Minimum Inhibitory Concentration of Commercially Available Pediatric Dentifrices: An In Vitro Study.

Aim: The aim of this study was to evaluate the antimicrobial efficacy and minimum inhibitory concentration (MIC) of commercially available pediatric dentifrices containing different compositions against Streptococcus mutans and Lactobacillus activity. Materials and methods: Four different commercially available brands of pediatric dentifrices, designated as sample I-fluoride, sample II-herbal, sample III-xylitol with nanosilver particles, and sample IV-xylitol with fluoride, along with two control groups (a positive control-ciprofloxacin and a negative control-distilled water), were tested for their antibacterial activity by measuring the zone of inhibition, followed by MIC against two dental bacterial pathogens, S. mutans strain and Lactobacillus acidophilus (LB) strain, at five different twofold dilutions of 100, 50, 25%, 12.5, and 6.25% concentrations. Result: All four dentifrices were found to have wide variations in their effectiveness against the two tested microorganisms at 100% (pure) and 50% concentrations, with sample I having the highest activity, followed by sample IV and sample II. At 25% concentration, only sample I and sample IV showed antibacterial activity, while at 12.5 and 6.25% concentrations, none of the tested toothpastes exhibited any antibacterial activity. Sample III failed to show antibacterial activity even in pure form against the two microorganisms. Conclusion: In our present study, the fluoride-containing pediatric dentifrice with a lower fluoride concentration (458 ppm) exhibited the highest zone of inhibition, followed by the xylitol with fluoride dentifrice and the herbal dentifrice. No zone of inhibition was observed in the nanosilver with xylitol dentifrice. How to cite this article: Dureha R, Navit S, Khan SA, et al. Comparative Evaluation of Antimicrobial Activity and Minimum Inhibitory Concentration of Commercially Available Pediatric Dentifrices: An In Vitro Study. Int J Clin Pediatr Dent 2024;17(8):938-944.

Mapping the Dental Applications of Nanosilver Fluoride: A Narrative Review.

Advances in nanotechnology have been changing the face of dentistry with their diverse range of dental applications. Silver nanoparticles (AgNPs) are a relatively new breakthrough in dentistry. Aim: The main objective of this paper is to discuss the current progress in the field of dentistry and highlight the aspects regarding silver nanoparticle incorporation, emphasizing the properties, applications, and advantages of nanosilver fluoride (NSF) that it brings to dentistry. Materials and methods: An extensive electronic scientific search was conducted on published articles in various databases, such as Medline (PubMed), CENTRAL (Cochrane), Scopus, and Web of Science, using the search terms AgNPs, nano dentistry, caries prevention, and oral health. Further brief communications, randomized controlled trials (RCT), in vitro research, and animal studies written in English were also considered. Case reports, editorial reviews, and opinion letters were excluded from the first phase of our research. Results: Pertaining to various kinds of literature reviews in journals, around 345 articles were retrieved. After screening, about 28 articles met all the selection criteria, focusing on NSF for the contemporary management of dental caries, emphasizing microinvasive therapeutic methods that can successfully halt the progression of caries at the initial level and minimize the loss of sound tooth structure. Conclusion: Due to its exceptional properties and wide range of clinical applications, AgNPs incorporated in fluoride may be employed as an effective, affordable, and improved anticaries agent that brings about superior enhancements in the fields of orthodontics, restorative dentistry, and pediatric and preventive dentistry. How to cite this article: Thimmaiah C, Thomas NA, Baskaradoss JK, et al. Mapping the Dental Applications of Nanosilver Fluoride: A Narrative Review. Int J Clin Pediatr Dent 2024;17(7):833-837.

Musa paradisiaca L. peel extract-bioinspired anisotropic nano-silver with the multipurpose of hydrogenation eco-catalyst and antimicrobial resistance.

In an effort to pursue a green synthesis approach, the biosynthesis of nano-silver (nAg) using plant extracts has garnered significant attention, particularly for its antimicrobial resistance and medical applications, which have been the focus of numerous studies. However, there remains a gap in surface catalytic studies, especially regarding the hydrogenation of 4-nitrophenol. While some studies have addressed catalytic kinetics, thermodynamic aspects have been largely overlooked, leaving the catalytic mechanisms of biosynthesized nAg unclear. In this context, the present work offers a straightforward, eco-friendly, and efficient protocol to obtain nano-silver inspired by Musa paradisiaca L. peel extract. This nAg serves multiple purposes, including antimicrobial resistance and as an eco-catalyst for hydrogenation. Predominantly consisting of zero-valent silver with anisotropic polyhedral shapes, mainly decahedra with an edge length of 50 nm, this nAg demonstrated effective antimicrobial action against both S. aureus and E. coli bacteria. More importantly, both kinetic and thermodynamic studies on the hydrogenation of 4-nitrophenol to 4-aminophenol catalyzed by this bio-inspired nAg revealed that the rate-limiting step is not diffusion-limited. Instead, the adsorbed hydrogen and 4-nitrophenolate react together via electron transfer on the surface of the nAg. The activation energy of 26.24 kJ mol-1 indicates a highly efficient eco-catalyst for such hydrogenation processes.

Biodistribution and toxic potential of silver nanoparticles when introduced to the female rat reproductive tract.

The prevalence of ionic silver and silver nanomaterials in hygiene products has been increasing due to their antimicrobial activity. While numerous studies have examined the effects of nanosilver in laboratory settings, there is a limited understanding of its impact on reproductive tissues, as well as its biodistribution and toxicity upon intra-vaginal exposure. If ionic or nanosilver enters adjacent and internal tissues via intra-vaginal exposure, the overuse of hygiene products containing silver may potentially threaten woman's health. This study investigated the effects of intra-vaginal silver exposure in Female Fischer 344 rats to single and multiple doses of a commercial product containing silver, along with standard nanosilver materials. Custom tampons were developed to simulate practical usage scenarios. The analysis of tissue biodistribution revealed that epithelial penetration and redistribution of silver was observed with most administered silver eliminated in feces (8-44 %), and secondary tissues containing 1-18 % of the dose, predominantly localized in the reproductive tract. In a subsequent toxicity study, vaginal histopathology indicated a cellular inflammatory reaction (neutrophil infiltration) associated with the presence of foreign silver material upon a single administration. Interestingly, no noticeable difference in histopathology incidence was observed upon multiple exposures to silver compared to the control group. Clinical chemistry and hematology analyses following acute exposure to silver nanomaterials showed no significant abnormalities. Overall, acute vaginal exposure to silver nanomaterials and ionic silver resulted in limited silver persistence, local tissue reactivity, epithelial penetration of silver resulting in accumulation in distant organs, and elimination primarily through feces. In vitro data suggested potential alterations in normal vaginal flora. Long-term studies are still lacking in this area.

Residual Stress and Warping Analysis of the Nano-Silver Pressureless Sintering Process in SiC Power Device Packaging.

Chip bonding, an essential process in power semiconductor device packaging, commonly includes welding and nano-silver sintering. Currently, most of the research on chip bonding technology focuses on the thermal stress analysis of tin-lead solder and nano-silver pressure-assisted sintering, whereas research on the thermal stress analysis of the nano-silver pressureless sintering process is more limited. In this study, the pressureless sintering process of nano-silver was studied using finite element software, with nano-silver as an interconnect material. Using the control variable method, we analyzed the influences of sintering temperature, cooling rate, solder paste thickness, and solder paste area on the residual stress and warping deformation of power devices. In addition, orthogonal experiments were designed to optimize the parameters and determine the optimal combination of the process parameters. The results showed that the maximum residual stress of the module appeared on the connection surface between the power chip and the nano-silver solder paste layer. The module warping deformation was convex warping. The residual stress of the solder layer increased with the increase in sintering temperature and cooling rate. It decreased with the increase in coating thickness. With the increase in the coating area, it showed a wave change. Each parameter influenced the stress of the solder layer in this descending order: sintering temperature, cooling rate, solder paste area, and solder paste thickness. The residual stress of the nano-silver layer was 24.83 MPa under the optimal combination of the process parameters and was reduced by 29.38% compared with the original value of 35.162 MPa.

Fighting sepsis-induced liver damage with biosynthesized silver nanoparticles.

Sepsis is a potentially fatal disease that arises from an infection and is characterized by an uncontrolled immune system reaction. Global healthcare systems bear a heavy financial burden from treating sepsis. This study aimed to provide information on the effective properties of silver nanoparticles derived from pomegranate peel extract (P-AgNP) against sepsis-induced hepatic injury. P-AgNPs were spherical with a diameter of ~19 nm. The animals were placed into four groups, each with seven rats. Group 1 functioned as the control group, receiving only saline for 7 days. Group 2 received only P-AgNPs at a dose of 20 mg/kg. To induce sepsis, groups 3 and 4 were given an intraperitoneal injection of 200 mg/mL cecal slurry. Sixty min later, group 4 was given 20 mg/kg of P-AgNPs daily for 7 days. The concentrations of reduced glutathione, nitric oxide, lipid peroxidation, and superoxide dismutase in liver homogenate were measured to determine the oxidative status. In addition, enzyme activities (alanine aminotransferase, aspartate amino transferase, and alkaline phosphatase) were measured. Furthermore, we investigated the histological changes, immunohistochemical expression of nuclear factor-κB, and mRNA levels of IL1ß, IL-6, TNF-α, Bax, BCl2, and Casp-3. P-AgNPs functioned as regulators in a sepsis model, successfully controlling altered gene expression. Following treatment, P-AgNPs improved tion and oxidative state, indicating a role in sepsis management. Based on our findings, we conclude that P-AgNPs have antioxidant activity and may be useful in preventing sepsis-induced liver inflammation, oxidative damage, and apoptosis. RESEARCH HIGHLIGHTS: Pomegranate peel-derived silver nanoparticles (P-AgNPs) enhanced liver function and oxidative state in rats with sepsis-induced hepatic damage. P-AgNPs reduced oxidative stress and liver inflammation via regulating inflammatory and apoptotic gene expression. P-AgNPs enhanced liver enzyme activities, histological structure, and immunohistochemistry expression of nuclear factor-κB.

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.

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

The 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. According to spectroscopic, volumetric, microscopic, dynamic light scattering measurements, pro-coagulant activity tests, and cellular inspection, we determine that at extremely low nanosilver concentrations (0.125-2.5µg ml-1), there is a relevant interaction effect on the serum albumin and red blood cells (RBCs). This explanation has its origin in the surface charge distribution of nanosilver particles 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. In contrast, the spherical nanosilver particle, by exhibiting isotropic surface charge, generates a polar environment comparable to the solvent. Both morphologies induce aggregation at NPs/bovine serum albumin ≈ 0.044 molar ratio values without altering the coagulation cascade tests; however, the spherical-shaped nanosilver exerts a negative impact on RBCs. Overall, our results suggest that the electron distributions of nanosilver particles, even at extremely low concentrations, are a critical factor influencing the molecular structure of blood proteins' and RBCs' membranes. Isotropic forms of nanosilver should be considered with caution, as they are not always the least harmful.

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.

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.

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.

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.

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.