Nano Silver-Induced Toxicity and Associated Mechanisms

Combined exposure of polystyrene nanoplastics and silver nanoparticles exacerbating hepatotoxicity in zebrafish mediated by ferroptosis pathway through increased silver accumulation

Silver nanoparticles (AgNPs) are extensively utilized for their antibacterial properties, leading to their release into the environment and subsequent bioaccumulation and biomagnification within the food chain. Polystyrene nanoplastics (PSNPs), as emerging pollutants, act as carriers for contaminants and alter their transformation processes. However, the toxicological effects and underlying mechanisms associated with the coexistence of these pollutants remain largely unexplored. Herein, the hepatotoxic effects and underlying mechanisms of acute combined exposure to PSNPs and AgNPs were explored using zebrafish as a model organism. After exposed to PSNPs and AgNPs, the larvae (120 hours post-fertilization) exhibited lipid metabolism disorders, increased oxidative stress, hepatomegaly, and liver dysfunction, with these effects being more pronounced than those observed with AgNPs exposure alone. This increase in hepatic toxicity may be due to the enhanced accumulation of AgNPs under combined exposure. Mechanistic investigations revealed that co-exposure led to a significant elevation in malondialdehyde and Fe2 + levels, a loss of mitochondrial cristae and a decrease in membrane potential, along with the abnormal expression of ferroptosis-related genes, which are hallmark indicators of ferroptosis. Furthermore, the introduction of the ferroptosis inhibitor deferoxamine alleviated all observed hepatotoxic phenotypes, thereby confirming that PS+AgNPs co-exposure induced liver injury through the ferroptosis pathway.

Green synthesis of magnesium oxide nanoparticles using the extract of Falcaria vulgaris to enhance the healing of burn wounds

Treating burn lesions has always been challenging because any product should be cheap, accessible, and have anti-bacterial commodities and tissue regeneration properties. The green synthesis of magnesium oxide nanoparticles (GS-MgONPs) can create an optimal prospect that is safe with low toxicity in biological tissue and better safety for application while including the antibacterial effect. This recent study aimed to evaluate the effectiveness of burn wound treatment using GS-MgONPs in rats. GS-MgONPs were synthesised for the first time using a Falcaria vulgaris extract (FVE) and characterised. Thirty male Wistar rats were divided into five groups: An untreated group, conventional product treated group, GS-MgONPs (1 wt%), GS-MgONPs (3 wt%) and 5. FVE (1 wt%). Treatments commenced immediately following burn induction and were administered daily for a duration of 21 d. GS-MgONPs showed a spherical morphology with a diameter of less than 100 nm. The NPs (1% and 3 wt%) and FVE demonstrated significant growth inhibition against Staphylococcus aureus while showing no cytotoxic effects on human fibroblast cells. The proposed subjects treated with 1 wt% and 3 wt% GS-MgONPs were able to significantly increase the rate of wound closure (p < 0.05). Histological observations revealed that collagen formation and epithelial regeneration were more pronounced in the groups receiving 1 wt% and 3 wt% MgONPs. These results indicate that GS-MgONPs effectively enhance the regeneration process.

Podocyte-related biomarkers' role in evaluating renal toxic effects of silver nanoparticles with the possible ameliorative role of resveratrol in adult male albino rats

Extensive uses of silver nanoparticles (Ag NPs) in different industries result in exposure to these nanoparticle imperatives in our daily lives. Resveratrol is found in many plants as a natural compound. The present study aimed to estimate the renal toxic effects of Ag NPs in adult male albino rats and the underlying relevant mechanisms while studying the possible role of resveratrol in ameliorating these effects. Thirty adult albino rats were split into 5 groups; control, vehicle, resveratrol (30 mg/kg), Ag NPs (300 mg/kg), and resveratrol + Ag NPs groups. The treatments were given orally for 4 weeks. Ag NPs group displayed a reduction in kidney weight ( absolute and relative), excess in urinary levels of kidney injury molecule, neutrophil gelatinase-associated lipocalin, cystatin, and blood kidney biomarkers (creatinine, urea, and potassium), increases in oxidative stress markers with the reduction in antioxidant markers, and decreases in serum sirtuin 1(SIRT1) level. Upregulation of interleukin 1 beta, tumor necrosis factor-alpha, and monocyte chemoattractant protein-1 gene expressions with downregulation of nephrin and podocin gene expressions in renal tissues were also observed. These changes were associated with histological alterations of the glomeruli and tubules, and increased area percentage of collagen fiber. A significant increase in the optical density of transforming growth factor-beta 1 and claudin-1 immunostaining was detected in the Ag NPs group when compared to other groups. All these changes were alleviated by the usage of resveratrol through its anti-oxidant, anti-inflammatory, and activation of SIRT1 recommending its use as a renoprotective agent.

Lipid-Coated Ag@MnO2 Core-Shell Nanoparticles for Co-Delivery of Survivin siRNA in Breast Tumor Therapy

Objective

Nanoparticles constructed with silver/manganese dioxide (Ag@MnO2) as the core, in conjunction with survivin siRNA (sis) and cyclo(RGD-DPhe-K) (Ag@MnO2-sis-c-L), were prepared for integrated tumor diagnosis and therapy.

Methods

Ag@MnO2-sis-c-L particles were prepared and characterized. The silver and manganese content were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES). The stability of sis in the system was evaluated by incubation with 50% FBS before the agarose gel electrophoresis experiment. The in vitro photothermal conversion ability, cytotoxicity to 4T1 cells, and cellular uptake of preparations were evaluated. The dialysis technique was employed to determine the in vitro release profile of Ag and Mn from Ag@MnO2-sis-c-L under various pH conditions. The pharmacokinetic behavior and tissue distribution of silver in vivo were detected by ICP-OES. Animal model experiments were conducted to further evaluate the anti-tumor efficacy of Ag@MnO2-sis-c-L against breast cancer in combination with infrared irradiation.

Results

Our newly synthesized Ag@MnO2-sis-c-L nanoparticles displayed superior physicochemical properties. The combined application of these nanoparticles with photothermal therapy (PTT) exerted the strongest synergistic inhibitory effects on tumor growth. Survivin protein expression in tumor tissues were markedly suppressed following delivery of nanoparticles loaded with sis. Additionally, magnetic resonance imaging revealed the high imaging capability of hybrid nanoparticles.

Conclusion

This study supports the potential utility of Ag@MnO2-sis-c-L coupled with PTT in therapeutic and diagnostic imaging applications.

Green synthesis and characterization of TiO2 nanoparticles from latex of Calatropis procera against dusky cotton bug

The dusky cotton bug is a small insect that poses a significant threat to cotton crops. Due to increasing reports on the development of resistance in this insect against insecticides, efforts to control this pest must involve other environment-friendly strategies. The use of nanoparticles (NPs) has generated an alternative pest control. The objective of this study was to evaluate the insecticidal effect of green synthesized titanium dioxide nanoparticles (TiO2) NPs using latex of Calatropis procera against dusky cotton bug 2nd and 4th instar nymph and adult stage. The optical properties of the synthesized nanoparticles were confirmed through UV-Vis spectroscopy whereas, surface morphology was checked through Scanning Electron Microscopy. A detailed XRD analysis of the synthesized particles confirmed that the particles belong to the anatase phase, of the tetragonal crystal system. When checked for their insecticidal potential against dusky cotton bugs (2nd and 4th instar nymph and adult stage) through the leaf dip method, the nanoparticles-controlled insect population was up to 95% with highest in 2nd instar nymphs and lowest in adults. However, the insecticidal activity was found directly proportional to the concentration of nanoparticles used.

Phytofabricated silver nanoparticles unlock new potential in tomato plants by combating wilt infection and enhancing plant growth

The environment faces serious threats from climate change, food security challenges, and a growing population. The UN Global Goals emphasize the urgent need for sustainable agriculture to secure food production. We must adopt innovative solutions to bolster agroecological resilience and increase food output with minimal environmental impact. Here, we investigate the antimycotic properties of silver nanoparticles (PP-AgNPs) at various concentrations in controlling Fusarium wilt for tomato crop improvement under laboratory, greenhouse, and field conditions. Various instruments were utilized to characterize the green-synthesized PP-AgNPs. The results indicated a broad UV peak at 428 nm and a spherical morphology with sizes ranging from 1 to 3.5 nm, as confirmed by SEM and TEM. Analyses indicate that the antifungal potency of PP-AgNPs (150 µg/mL) against Fusarium oxysporum was found to be 80.9% (Colony diameter: DA) and 95.4% (Measured area -MA), respectively, in contrast to the control treatment. Notably, the concentration of PP-AgNPs at 100 µg/mL signified the best effect under greenhouse and field trials, reducing disease severity by 34.5% (greenhouse) and 21.8% (Field: average of both years). PP-AgNPs also render other benefits, including improved plant growth parameters, fruit weight, number, and bioactive compounds. After exposure to PP-AgNPs, there was a significant increase in the expression of pathogenicity-related (PR), and defense genes at the molecular level. The physiological and molecular data are in-line induced antioxidative and defense responses after treatment with PP-AgNPs. Furthermore, the Ag content in various parts of tomato plants reveals no adverse effect on plant yield. Current research indicates that PP-AgNPs may be an effective and sustainable product for managing diseases and increasing crop yields in agriculture.

A mini review on the regulation of coagulation homeostasis through interfering with vitamin K-dependent coagulation/anticoagulation factors

Coagulation disorders, such as excessive bleeding or thrombosis, present significant health challenges. Vitamin K-dependent proteins (VKDPs), including coagulation and anticoagulation factors, are essential for maintaining the coagulation homeostasis due to their key roles in the coagulation cascade. Therefore, VKDPs have become significant targets for regulating coagulation homeostasis, and various strategies have been developed, primarily including small molecule drugs and nanomaterials. This review presents the summary of these strategies, focusing on the mechanisms, effectiveness and limitations. It first discusses the pivotal role of VKDPs in the coagulation cascade, followed by an in-depth analysis of how small molecule drugs and nanomaterials to regulate hemostasis through interfering with VKDPs. Furthermore, this review addresses the challenges faced in the current approaches and potential future research directions. We hope this review will contribute to advancing the development of novel methods for modulating coagulation homeostasis through VKDP interference.

Silver Nanoparticles: A Versatile Tool Against Infectious and Non-Infectious Diseases

Silver nanoparticles possess remarkable properties that render them highly beneficial for medical applications in both infectious and non-infectious diseases. Among their most renowned attributes is their antimicrobial activity. They have demonstrated efficacy against a wide range of bacteria, fungi, protozoa, and viruses. Additionally, the antitumor and anti-diabetic properties of silver nanoparticles, along with their ability to promote wound healing and their application as biosensors, underscore their therapeutic potential for various non-infectious conditions. As silver nanoparticles are employed for medical purposes, their potential toxicity must be considered. While silver nanoparticles present a promising alternative in the therapeutic domain, further research is needed to elucidate their precise mechanisms of action, optimize their efficacy, and mitigate any potential health risks associated with their use.

Functionalization of collagen fiber with nano-islands of silver via atomic layer deposition to promote bone healing

Modern techniques of thin film deposition (e.g., atomic layer deposition [ALD]) have paved the way for the modification of the surface of target substrates with thin films, nanoparticles, or other types of nanomaterials. This novel way can improve the base material's properties and enhance specific properties through adding functionalized groups to the surface. In this study, ALD of silver was conducted on commercially available Type I collagen membrane to improve its bioactivity and promote bone healing. Two different sample groups were studied: pristine collagen and silver-coated collagen via ALD (Ag/Collagen). Chemical and morphological changes of the collagen membrane were investigated with X-ray photoelectron spectroscopy and scanning electron microscopy and the bioactivity of functionalized collagen with silver was studied in vitro and in vivo. Nano-islands of silver were obtained on collagen fibrils with an average diameter of ∼16 nm. Comparison of gingival cells cultured on pristine collagen, and silver-coated collagen, demonstrated that the attained silver nanoparticle size and concentration are below the toxicity level of silver. In vivo assessment in rat model showed the biocompatibility of the Ag/Collagen, and greater new bone formation compared to control. This novel solvent-free method can be used to functionalize sensitive materials used in surgeries as bone grafting agents to enhance osteopromotive properties without any adverse effects to the cellular environment.

Exploring quercetin's protective potential against the pro-inflammatory effects of silver nanoparticles in C57BL/6J mice

The increasing prevalence of silver nanoparticles (AgNP) in various applications has sparked concerns about their potential adverse effects on human health. Hence, it is crucial to devise strategies to minimize their detrimental effects. Quercetin, a naturally occurring flavonoid present in human diet is known for its broad biological effects, including anti-inflammatory properties. Considering this, quercetin could serve as a promising strategy to protect the body against the harmful effects of AgNP. Thus, this study aimed to evaluate the potential protective role of quercetin against the deleterious effects induced by 5 nm polyvinylpyrrolidone (PVP)-AgNP in C57BL/6J mice. Using a novel administration technology (HaPILLness), mice were given a daily oral dose of AgNP at 1 mg/kg body weight (bw) or 10 mg/kg bw for 14 days, combined with daily IP injections of quercetin at 1 mg/kg bw. Our findings demonstrate that quercetin effectively attenuated the AgNP-induced intestinal inflammatory response, as demonstrated by reduced histological vascular and cellular alterations, along with a notable decrease in cytokine production, attributed to the inhibition of the nuclear factor (NF)-кB inflammatory pathway. Quercetin's protective effects extended to the liver and lungs, by reversing changes in the inflammatory and antioxidant markers cluster of differentiation (CD)4, superoxide dismutase 1 (SOD1) and catalase.

Graphene SU-8 Platform for Enhanced Cardiomyocyte Maturation and Intercellular Communication in Cardiac Drug Screening

Cell culture substrates designed for myocardial applications are pivotal in promoting the maturation and functional integration of cardiomyocytes. However, traditional in vitro models often inadequately mimic the diverse biochemical signals and electrophysiological properties of mature cardiomyocytes. Herein, we propose the application of monolayer graphene, transferred onto SU-8 cantilevers integrated with a microelectrode array, to evaluate its influence on the structural, functional, and electro-mechano-physiological properties of cardiomyocytes. The monolayer graphene, prepared using chemical vapor deposition, is adeptly transferred to the target substrates via thermal release tape. The electrical conductivity of these graphene-enhanced SU-8 substrates is about 1600 S/cm, markedly surpassing that of previously reported cell culture substrates. Immunofluorescence staining and Western blot analyses reveal that the electrically conductive graphene significantly enhances cardiomyocyte maturation and cardiac marker expression compared to bare SU-8 substrates. Cardiomyocytes cultured on graphene-transferred substrates exhibit conduction velocity approximately 3.4 times greater than that of the control group. Such improvements in cardiac marker expression, mechano-electrophysiological performance lead to better responsiveness to cardiovascular drugs, such as Verapamil and Isoproterenol. While the graphene monolayer does not fully replicate the complex environment found in native cardiac tissue, its use on SU-8 substrates offers a feasible approach for accelerating cardiomyocyte maturation and facilitating drug screening applications.

The Substantial Role of Cell and Nanoparticle Surface Properties in the Antibacterial Potential of Spherical Silver Nanoparticles

Purpose

Although it is well known that the size, shape, and surface chemistry affect the biological potential of silver nanoparticles (AgNPs), the published studies that have considered the influence of AgNP surface on antibacterial activity have not provided conclusive results. This is the first study whose objective was to determine the significance of the surface net charge of AgNPs on their antibacterial potential, attraction to bacterial cells, and cell envelope disruption, considering differences in bacterial surface properties.

Methods

We evaluated five commercial AgNP colloids with identical size and shape but different surface ligands. We thoroughly characterized their physicochemical properties, including the zeta potential, hydrodynamic diameter, and polydispersity index, and determined the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC), along with silver absorption into bacterial cells. Moreover, we investigated structural changes in bacteria treated with AgNPs by using a crystal violet assay and electron microscopy.

Results

The zeta potential of AgNPs ranged from -47.6 to +68.5 mV, with a hydrodynamic diameter of 29-87 nm and a polydispersity index of 0.349-0.863. Bacterial susceptibility varied significantly (0.5 ≤ MIC ≤ 256 µg Ag/mL; 1 ≤ MBC ≤ 256 µg Ag/mL); we found the lowest susceptibility in bacteria with a cell wall or a polysaccharide capsule. The most active AgNPs (0.5 ≤ MIC ≤ 32 µg Ag/mL; 2 ≤ MBC ≤ 64 µg Ag/mL) had a moderate surface charge (-21.5 and +14.9 mV). The antibacterial potential was unrelated to ion dissolution or cell envelope disruption, and bacterial cells absorbed less of the most active AgNPs (1.75-7.65%).

Conclusion

Contrary to previous reports, we found that a moderate surface charge is crucial for the antibacterial activity of AgNPs, and that a significant attraction of the nanoparticle to the cell surface reduces the antibacterial potential of AgNPs. These findings challenge the existing views on AgNP antibacterial mechanisms and interactions with bacterial cells.

Enhancing wound healing through sonodynamic silver/barium titanate heterostructures-loading gelatin/PCL nanodressings

Bacterial infections present a formidable challenge in surgical procedures, and are a major threat to wound healing. Sonodynamic therapy (SDT) is a non-invasive approach for fighting pathogens; however, it is hindered by the efficiency of sonosensitizers and effective antibacterial time. In this study, we developed a biocompatible nanodressing to improve the antibacterial efficacy and accelerate wound healing via SDT. Silver nanoparticles (NPs) were synthesized on tetragonal barium titanate (BTO) NPs to create an Ag@BTO heterostructure of sonosensitizers to improve their piezocatalytic activities, which were then incorporated into gelatin/polycaprolactone (PCL) to form Ag@BTO-gelatin/PCL nanofiber (ABT-gP NFs) dressings. The loading of Ag@BTO NPs resulted in ABT-gP NFs with better mechanical properties and excellent piezocatalysis, which produced reactive oxygen species and Ag+ to kill bacteria during ultrasound (US) irradiation. Additionally, nanodressing released moderate amounts of silver ions without US, prolonging the antibacterial time, while promoting fibroblast migration. This approach was effective in killing Gram-positive and Gram-negative bacteria (100 % and 90.8 %, respectively), promoting cell migration in vitro and accelerating wound healing without adverse effects in vivo. This study extends the potential applications of ultrasound-triggered nanodressing to the field of wound healing.

Biliary stents for active materials and surface modification: Recent advances and future perspectives

Demand for biliary stents has expanded with the increasing incidence of biliary disease. The implantation of plastic or self-expandable metal stents can be an effective treatment for biliary strictures. However, these stents are nondegradable and prone to restenosis. Surgical removal or replacement of the nondegradable stents is necessary in cases of disease resolution or restenosis. To overcome these shortcomings, improvements were made to the materials and surfaces used for the stents. First, this paper reviews the advantages and limitations of nondegradable stents. Second, emphasis is placed on biodegradable polymer and biodegradable metal stents, along with functional coatings. This also encompasses tissue engineering & 3D-printed stents were highlighted. Finally, the future perspectives of biliary stents, including pro-epithelialization coatings, multifunctional coated stents, biodegradable shape memory stents, and 4D bioprinting, were discussed.

Biotoxicity of silver nanoparticles complicated by the co-existence of micro-/nano-plastics

Silver nanoparticles (AgNP) and polystyrene (PS) plastics have been broadly utilized in various field, e.g., food storage, packaging materials, and medical therapies. However, investigation on the potential biotoxicity induced by the co-exposure to AgNP and PS plastics remains understudied. Thus, we performed this study to examine the toxicological profile of the co-exposure to AgNP and PS in mice. Biochemical and microbial characterizations were performed in mice receiving 90-day oral gavage feeding to examine the hepatotoxicity, neurotoxicity, inflammatory responses, gut microbial alterations. It has been found that the presence of plastic particles aggravates the toxicity of silver nanoparticle materials. Regardless of the plastic type and size, energy and choline metabolisms will be altered by the co-exposures. Moreover, microplastics may induce cell damage by modulating fatty acid peroxidation in unison with stimulating inflammatory responses. Due to the smaller size of nanoplastics, they may pass through blood-brain barrier to induce neuronal damage and increase vascular risks. Changes in the microbial functional abundances are sensitive to the microplastics doses. These results support the necessity of reducing the co-exposure between AgNP and multiscale plastics, and advocate further developments of biodegradable package materials to improve food safety.

In vitro cytotoxicity assessment of carbonaceous gels for bone marrow mesenchymal stem cells

The current work aimed to elucidate the potential applications of the carbonaceous gels and assess the in vitro cytotoxicity of these gels when suspended in a culture medium and exposed to bone marrow mesenchymal stem cells. Cellular viability, cell cycle distribution, apoptotic cell death, and mitochondrial membrane potential in bone marrow mesenchymal stem cells co-incubated with different concentrations of carbonaceous gels (0.1, 1, 10, 50, and 100 μg/mL) were evaluated. Flow cytometry and immunofluorescence were used to investigate apoptosis and cell cycle distribution. The expression of associated apoptotic proteins was analysed using Western Blot. Although the co-incubation of carbonaceous gels did not significantly affect cell viability, high dosages (100 μg/mL) of these gels led to cellular dysfunction. Specifically, cells exposed to high concentrations of these gels exhibited G2-phase arrest and increased levels of reactive oxygen species. However, the reported impacts did not cause considerable cell death. At the same time, carbonaceous gels did not significantly induce apoptosis. Compared to other carbon nanomaterials, carbonaceous gels' biotoxicity was relatively low, suggesting their potential for various biological applications. Nonetheless, caution should be exercised when considering the concentration of carbonaceous gels for future medical applications.

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.

Comprehensive insights into mechanism of nanotoxicity, assessment methods and regulatory challenges of nanomedicines

Nanomedicine has the potential to transform healthcare by offering targeted therapies, precise diagnostics, and enhanced drug delivery systems. The National Institutes of Health has coined the term "nanomedicine" to describe the use of nanotechnology in biological system monitoring, control, diagnosis, and treatment. Nanomedicine continues to receive increasing interest for the rationalized delivery of therapeutics and pharmaceutical agents to achieve the required response while reducing its side effects. However, as nanotechnology continues to advance, concerns about its potential toxicological effects have also grown. This review explores the current state of nanomedicine, focusing on the types of nanoparticles used and their associated properties that contribute to nanotoxicity. It examines the mechanisms through which nanoparticles exert toxicity, encompassing various cellular and molecular interactions. Furthermore, it discusses the assessment methods employed to evaluate nanotoxicity, encompassing in-vitro and in-vivo models, as well as emerging techniques. The review also addresses the regulatory issues surrounding nanotoxicology, highlighting the challenges in developing standardized guidelines and ensuring the secure translation of nanomedicine into clinical settings. It also explores into the challenges and ethical issues associated with nanotoxicology, as understanding the safety profile of nanoparticles is essential for their effective translation into therapeutic applications.

Development of Hematite Nano Ellipsoids/Pectin Composite Films for Green Packaging Applications

Synthetic packaging materials are known to cause serious environmental and human health problems. Among the eco-friendly biopolymers from nonfood sources that are suitable for packaging applications, pectin is a promising candidate. However, native pectin films (NPF) exhibit poor mechanical strength, high hydrophilicity, and poor gas diffusion barrier properties. These shortcomings offset the advantages of pectin as a potential packaging material. To address these limitations, in this study, hematite nano ellipsoids (HNEs) were incorporated as fillers to reinforce native pectin films. This reinforcement resulted in substantial improvements in the mechanical properties, hydrophobicity, thermal stability, barrier properties, and optical attributes of pectin films. Compared to NPF, the pectin-hematite composite film exhibited a 35% increase in tensile strength, a 30° increase in contact angle, a 6-fold increase in the oxygen diffusion barrier properties, and a 20% increase in the water vapor barrier properties. This study presents a sustainable, biocompatible, and biodegradable packaging solution by capitalizing on eco-friendly biopolymer and nanoparticle engineering.

Silver nanoparticle-induced cell damage via impaired mtROS-JNK/MnSOD signaling pathway

This study investigated the mechanism of silver nanoparticle (AgNP) cytotoxicity from a mitochondrial perspective. The effect of AgNP on manganese superoxide dismutase (MnSOD), a mitochondrial antioxidant enzyme, against oxidative stress has not been studied in detail. We demonstrated that AgNP decreased MnSOD mRNA level, protein expression, and activity in human Chang liver cells in a time-dependent manner. AgNP induced the production of mitochondrial reactive oxygen species (mtROS), particularly superoxide anion. AgNP was found to increase mitochondrial calcium level and disrupt mitochondrial function, leading to reduced ATP level, succinate dehydrogenase activity, and mitochondrial permeability. AgNP induced cytochrome c release from the mitochondria into the cytoplasm, attenuated the expression of the anti-apoptotic proteins phospho Bcl-2 and Mcl-1, and induced the expression of the pro-apoptotic proteins Bim and Bax. In addition, c-Jun N-terminal kinase (JNK) phosphorylation was significantly increased by AgNP. Treatment with elamipretide (a mitochondria-targeted antioxidant) and SP600125 (a JNK inhibitor) showed the involvement of MnSOD and JNK in these processes. These results indicated that AgNP damaged human Chang liver cells by destroying mitochondrial function through the accumulation of mtROS.

Physical, mechanical and antibacterial properties of the orthodontic adhesive doped with S-TiO2

Orthodontic adhesive doped with sulfur-modified TiO2 promotes antibacterial effect. The objective of the study was to characterize the physical, mechanical and antibacterial properties of the orthodontic bracket adhesive, doped with modified titanium dioxide nanoparticles. Sulfur-doped TiO2 was synthetized and morphological topography was analyzed with TEM and SEM imaging. The catalytic performance during the degradation of rhodamine B was assessed. Nanomaterial was added at four concentration (1, 3, 6, and 10 wt%) to a commercial orthodontic adhesive. The shear bond strength and microhardness of a resin-based orthodontic adhesive containing S-TiO2 were evaluated. The inhibitory effect of the pure and doped adhesives against Escherichia coli and Streptococcus mutans was examined. As the results, the highest antimicrobial activity and good adhesive properties were noticed for light-cured orthodontic adhesive doped with 3% of S-TiO2. In this case, orthodontic adhesives with strong and long-lasting bactericidal properties can be created through the incorporation of modified TiO2 without negatively influencing microhardnesses, and bonding ability. White spot lesion and demineralization, which occurs very often in patients during orthodontic treatment, can be therefore minimized.

Advances in silver nanoparticles: a comprehensive review on their potential as antimicrobial agents and their mechanisms of action elucidated by proteomics

Nanoparticles play a crucial role in the field of nanotechnology, offering different properties due to their surface area attributed to their small size. Among them, silver nanoparticles (AgNPs) have attracted significant attention due to their antimicrobial properties, with applications that date back from ancient medicinal practices to contemporary commercial products containing ions or silver nanoparticles. AgNPs possess broad-spectrum biocidal potential against bacteria, fungi, viruses, and Mycobacterium, in addition to exhibiting synergistic effects when combined with certain antibiotics. The mechanisms underlying its antimicrobial action include the generation of oxygen-reactive species, damage to DNA, rupture of bacterial cell membranes and inhibition of protein synthesis. Recent studies have highlighted the effectiveness of AgNPs against various clinically relevant bacterial strains through their potential to combat antibiotic-resistant pathogens. This review investigates the proteomic mechanisms by which AgNPs exert their antimicrobial effects, with a special focus on their activity against planktonic bacteria and in biofilms. Furthermore, it discusses the biomedical applications of AgNPs and their potential non-preparation of antibiotic formulations, also addressing the issue of resistance to antibiotics.

Nanomedicines targeting activated immune cells and effector cells for rheumatoid arthritis treatment

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovial inflammation and inflammatory cellular infiltration. Functional cells in the RA microenvironment (RAM) are composed of activated immune cells and effector cells. Activated immune cells, including macrophages, neutrophils, and T cells, can induce RA. Effector cells, including synoviocytes, osteoclasts, and chondrocytes, receiving inflammatory stimuli, exacerbate RA. These functional cells, often associated with the upregulation of surface-specific receptor proteins and significant homing effects, can secrete pro-inflammatory factors and interfere with each other, thereby jointly promoting the progression of RA. Recently, some nanomedicines have alleviated RA by targeting and modulating functional cells with ligand modifications, while other nanoparticles whose surfaces are camouflaged by membranes or extracellular vesicles (EVs) of these functional cells target and attack the lesion site for RA treatment. When ligand-modified nanomaterials target specific functional cells to treat RA, the functional cells are subjected to attack, much like the intended targets. When functional cell membranes or EVs are modified onto nanomaterials to deliver drugs for RA treatment, functional cells become the attackers, similar to arrows. This study summarized how diversified functional cells serve as targets or arrows by engineered nanoparticles to treat RA. Moreover, the key challenges in preparing nanomaterials and their stability, long-term efficacy, safety, and future clinical patient compliance have been discussed here.

Implications of silver nanoparticles for H. pylori infection: modulation of CagA function and signaling

Background

Helicobacter pylori infection poses a significant health burden worldwide, and its virulence factor CagA plays a pivotal role in its pathogenesis.

Methods

In this study, the interaction between H. pylori-infected AGS cells and silver nanoparticles (AgNPs) was investigated, with a focus on the modulation of CagA-mediated responses, investigated by western blotting. Both, the dose-dependent efficacy against H. pylori (growth curves, CFU assay) and the impact of the nanoparticles on AGS cells (MTT assay) were elucidated.

Results

AGS cells infected with H. pylori displayed dramatic morphological changes, characterized by elongation and a migratory phenotype, attributed to CagA activity. Preincubation of H. pylori with AgNPs affected these morphological changes in a concentration-dependent manner, suggesting a correlation between AgNPs concentration and CagA function.

Conclusion

Our study highlights the nuanced interplay between host-pathogen interactions and the therapeutic potential of AgNPs in combating H. pylori infection and offers valuable insights into the multifaceted dynamics of CagA mediated responses.

A neoteric antibacterial ceria-silver nanozyme for abiotic surfaces

Community-associated and hospital-acquired infections caused by bacteria continue to yield major global challenges to human health. Bacterial contamination on abiotic surfaces is largely spread via high-touch surfaces and contemporary standard disinfection practices show limited efficacy, resulting in unsatisfactory therapeutic outcomes. New strategies that offer non-specific and broad protection are urgently needed. Herein, we report our novel ceria-silver nanozyme engineered at a molar ratio of 5:1 and with a higher trivalent (Ce3+) surface fraction. Our results reveal potent levels of surface catalytic activity on both wet and dry surfaces, with rapid, and complete eradication of Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin resistant S. aureus, in both planktonic and biofilm form. Preferential electrostatic adherence of anionic bacteria to the cationic nanozyme surface leads to a catastrophic loss in both aerobic and anaerobic respiration, DNA damage, osmodysregulation, and finally, programmed bacterial lysis. Our data reveal several unique mechanistic avenues of synergistic ceria-Ag efficacy. Ag potentially increases the presence of Ce3+ sites at the ceria-Ag interface, thereby facilitating the formation of harmful H2O2, followed by likely permeation across the cell wall. Further, a weakened Ag-induced Ce-O bond may drive electron transfer from the Ec band to O2, thereby further facilitating the selective reduction of O2 toward H2O2 formation. Ag destabilizes the surface adsorption of molecular H2O2, potentially leading to higher concentrations of free H2O2 adjacent to bacteria. To this end, our results show that H2O2 and/or NO/NO2-/NO3- are the key liberators of antibacterial activity, with a limited immediate role being offered by nanozyme-induced ROS including O2•- and OH•, and likely other light-activated radicals. A mini-pilot proof-of-concept study performed in a pediatric dental clinic setting confirms residual, and continual nanozyme antibacterial efficacy over a 28-day period. These findings open a new approach to alleviate infections caused by bacteria for use on high-touch hard surfaces.

Biomimetic microfluidic chips for toxicity assessment of environmental pollutants

Various types of pollutants widely present in environmental media, including synthetic and natural chemicals, physical pollutants such as radioactive substances, ultraviolet rays, and noise, as well as biological organisms, pose a huge threat to public health. Therefore, it is crucial to accurately and effectively explore the human physiological responses and toxicity mechanisms of pollutants to prevent diseases caused by pollutants. The emerging toxicological testing method biomimetic microfluidic chips (BMCs) exhibit great potential in environmental pollutant toxicity assessment due to their superior biomimetic properties. The BMCs are divided into cell-on-chips and organ-on-chips based on the distinctions in bionic simulation levels. Herein, we first summarize the characteristics, emergence and development history, composition and structure, and application fields of BMCs. Then, with a focus on the toxicity mechanisms of pollutants, we review the applications and advances of the BMCs in the toxicity assessment of physical, chemical, and biological pollutants, respectively, highlighting its potential and development prospects in environmental toxicology testing. Finally, the opportunities and challenges for further use of BMCs are discussed.

Toxic effects on ciliates under nano-/micro-plastics coexist with silver nanoparticles

Owing to the degradation of plastics, microplastics (MPs) and nanoplastics (NPs) have remained the focus of global attention. Silver nanoparticles (AgNPs) could adversely affect marine organisms due to their broad application. So far, the combined effects of MPs/NPs (strong adsorbents) with AgNPs on marine organisms are scant. Thus, four sizes polystyrene beads (80 nm, 220 nm, 1.07 µm, and 2.14 µm) combined with AgNPs (30 nm) were assessed using ciliated protozoa Uronema marinum. Results showed that MPs/NPs dramatically decrease the abundance, biovolume, and carbon biomass of U. marinum. And, exposure could cause changes of antioxidant enzyme activity and antioxidant content on U. marinum. The combined toxicity of MPs/NPs with AgNPs to ciliates showed an enhanced effect compared to exposure alone. Additionally, the negative effects under exposure of NPs plus AgNPs were more significant than those of MPs plus AgNPs. Transcriptome sequencing showed that co-exposure could affect the energy metabolism and lipid metabolism of ciliates, even cause DNA and protein damage. Our study provided a novel insight and first-hand basic data for the understanding of combined toxicity of MPs /NPs with AgNPs on the basic trophic level ciliated protozoa in marine ecosystems.

Toxicity mechanism of engineered nanomaterials: Focus on mitochondria

With the rapid development of nanotechnology, engineered nanomaterials (ENMs) are widely used in various fields. This has exacerbated the environmental pollution and human exposure of ENMs. The study of toxicity of ENMs and its mechanism has become a hot research topic in recent years. Mitochondrial damage plays an important role in the toxicity of ENMs. This paper reviews the structural damage, dysfunction, and molecular level perturbations caused by different ENMs to mitochondria, including ZnO NPs, Ag NPs, TiO2 NPs, iron oxide NPs, cadmium-based quantum dots, CuO NPs, silica NPs, carbon-based nanomaterials. Among them, mitochondrial quality control plays an important role in mitochondrial damage. We further summarize the cellular level outcomes caused by mitochondrial damage, mainly including, apoptosis, ferroptosis, pyroptosis and inflammation response. In addition, we concluded that reducing mitochondrial damage at source as well as accelerating recovery from mitochondrial damage through ENMs modification and pharmacological intervention are two feasible strategies. This review further provides new insights into the mitochondrial toxicity mechanisms of ENMs and provides a new foothold for predicting human health and environmental risks of ENMs.

Fabrication of controlled-release silver nanoparticle polylactic acid microneedles with long-lasting antibacterial activity using a micro-molding solvent-casting technique

Most topical drug delivery techniques do not provide therapeutic concentrations for treatment of surgical site and other local infections and, therefore, require some kind of enhancement, such as physical methods like microneedles, the subject of the present investigation. Here, controlled-release long-lasting antibacterial polylactic acid (PLA) microneedles containing 1, 3, and 5% silver nanoparticles (AgNP) were prepared using micro-molding solvent-casting technique. Microneedles were characterized using optical microscopy, SEM, FTIR, XRD, and DSC. Also, mechanical strength, barrier disruption ability, insertion depth, in-vitro release kinetics, antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, and silver permeation through rat skin were studied. Microneedles showed good mechanical strength with no signs of failure at an optimum PLA concentration of 25% (w/v). FTIR revealed no chemical interaction between ingredients, and XRD confirmed presence of AgNP in microneedles. Microneedles penetrated the skin model at depth of up to 1143 μm resulting 5-7 times increase in transepidermal water loss (TEWL). Release studies showed 2.2, 6.8, and 8.1 µg silver release from the whole body (obeying Higuchi's release model) and 0.33, 0.45, and 0.78 µg from the needles alone (obeying Fickian-cylindrical type release) for 1, 3, and 5% AgNP microneedles, respectively. Also, prolonged antibacterial activity (for 34 days) was observed. Skin studies over 72 h indicated that besides needles, silver is also released from the baseplate which had a marginal share in total silver permeation through the skin. In conclusion, a straightforward solvent-casting technique can be used to successfully prepare strong AgNP-containing PLA microneedles capable of long-lasting antibacterial activity.

Metal-Based Nanoparticles for Cardiovascular Diseases

Globally, cardiovascular diseases (CVDs) are the leading cause of death and disability. While there are many therapeutic alternatives available for the management of CVDs, the majority of classic therapeutic strategies were found to be ineffective at stopping or significantly/additionally slowing the progression of these diseases, or they had unfavorable side effects. Numerous metal-based nanoparticles (NPs) have been created to overcome these limitations, demonstrating encouraging possibilities in the treatment of CVDs due to advancements in nanotechnology. Metallic nanomaterials, including gold, silver, and iron, come in various shapes, sizes, and geometries. Metallic NPs are generally smaller and have more specialized physical, chemical, and biological properties. Metal-based NPs may come in various forms, such as nanoshells, nanorods, and nanospheres, and they have been studied the most. Massive potential applications for these metal nanomaterial structures include supporting molecular imaging, serving as drug delivery systems, enhancing radiation-based anticancer therapy, supplying photothermal transforming effects for thermal therapy, and being compounds with bactericidal, fungicidal, and antiviral qualities that may be helpful for cardiovascular diseases. In this context, the present paper aims to review the applications of relevant metal and metal oxide nanoparticles in CVDs, creating an up-to-date framework that aids researchers in developing more efficient treatment strategies.

Green Synthesis of Silver Nanoparticles using Cirsium congestum Extract Modified by Chitosan/Alginate: Bactericidal Activity against Pathogenic Bacteria and Cytotoxicity Analysis in Normal Cell Line

AIM

The study aimed to determine in vitro pharmacological effects of modified Ag nanoparticles (AgNPs).

BACKGROUND

AgNPs are considered antimicrobial agents. However, the cytotoxicity of chemically synthesized AgNPs (cAgNPs) has raised challenges that limit their use.

OBJECTIVE

The purpose of the study was to examine the antimicrobial and cytotoxicity effects of AgNPs synthesized using Cirsium congestum extract modified by chitosan/alginate AgNPS (Ch/ALG-gAgNPs).

METHODS

Nanoparticles were characterized using TEM, DLS, XRD, and FTIR. Resistant strains of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were used for the antimicrobial analysis of Ch/ALG-gAgNPs using disc diffusion and microdilution methods. The effects of NPs on cell viability and apoptosis in L929 normal cells were determined using MTT assay and annexin/PI staining, respectively.

RESULTS

Physicochemical characterizations confirmed Ch/ALG-gAgNPs to be spherical and uniformly dispersed, and their size ranged from 50 to 500 nm. Ch/ALG-gAgNPs inhibited the growth of microbial strains in a dose-dependent manner. The antibacterial effect of Ch/ALG-gAgNPs was significantly higher than cAgNPs. The Ch/ALG-gAgNPs showed little cytotoxicity against normal cells at concentrations less than 50 μg/ml. Cytotoxicity effects of Ch/ALG-gAgNP were less than cAgNPs. Flow cytometry and real-time PCR results showed a decrease in apoptosis percentage and BAX marker in the presence of Ch/ALG-gAgNPs relative to when the cell was treated with cAgNPs.

CONCLUSION

Current findings introduce novel gAgNPs modified with chitosan/alginate for use in medicine.

Porous Polymersomes as Carriers for Silver Nanoparticles and Nanoclusters: Advantages of Compartmentalization for Antimicrobial Usage

The global threat to public health posed by antibiotic-resistant bacterial infections requires the exploration of innovative approaches. Nanomaterials, particularly silver nanoparticles (AgNPs) and nanoclusters (AgNCs), have emerged as potential solutions to address the pressing issue of a bacterial healthcare crisis. However, the high cytotoxicity levels and low stability associated with AgNPs and AgNCs limit their applicability. To overcome these challenges, AgNCs and AgNPs were synthesized in the presence of porous polymersomes, resulting in a compartmentalized system that enhances stability, reduces cytotoxicity, and maintains high antimicrobial activity. The encapsulated particles exhibit a distribution of silver components on both the surface and the core, which is confirmed through the analysis of surface charge and center of mass. Moreover, our investigation demonstrates improved stability of the nanoparticles and nanoclusters upon entrapment in the porous system, as evidenced by the ion release assay. The antimicrobial effectiveness of porous polymersomes containing AgNPs and AgNCs was demonstrated by visualizing the biofilms and quantifying the penetration depth. Furthermore, cytotoxicity studies showed that compartmentalization increases cell compatibility for AgNC-based systems, showcasing the many advantages this system holds.

Green Synthesis and Characterization of Silver Nanoparticles Using Azadirachta indica Seeds Extract: In Vitro and In Vivo Evaluation of Anti-Diabetic Activity

BACKGROUND

Diabetes mellitus (DM) is a non-communicable, life-threatening syndrome that is present all over the world. The use of eco-friendly, cost-effective, and green-synthesised nanoparticles as a medicinal therapy in the treatment of DM is an attractive option.

OBJECTIVE

In the present study, silver nanoparticles (AI-AgNPs) were biosynthesized through the green synthesis method using Azadirachta indica seed extract to evaluate their anti-diabetic potentials.

METHODS

These nanoparticles were characterized by using UV-visible spectroscopy, Fourier transform infrared spectrophotometers (FTIR), scanning electron microscopy (SEM), DLS, and X-ray diffraction (XRD). The biosynthesized AI-AgNPs and crude extracts of Azadirachta indica seeds were evaluated for anti-diabetic potentials using glucose adsorption assays, glucose uptake by yeast cells assays, and alpha-amylase inhibitory assays.

RESULTS

Al-AgNPs showed the highest activity (75 ± 1.528%), while crude extract showed (63 ± 2.5%) glucose uptake by yeast at 80 µg/mL. In the glucose adsorption assay, the highest activity of Al-AgNPs was 10.65 ± 1.58%, while crude extract showed 8.32 ± 0.258% at 30 mM, whereas in the alpha-amylase assay, Al-AgNPs exhibited the maximum activity of 73.85 ± 1.114% and crude extract 65.85 ± 2.101% at 100 µg/mL. The assay results of AI-AgNPs and crude showed substantial dose-dependent activities. Further, anti-diabetic potentials were also investigated in streptozotocin-induced diabetic mice. Mice were administered with AI-AgNPs (10 to 40 mg/kg b.w) for 30 days.

CONCLUSIONS

The results showed a considerable drop in blood sugar levels, including pancreatic and liver cell regeneration, demonstrating that AI-AgNPs have strong anti-diabetic potential.

Improving the biocompatibility and antibacterial efficacy of silver nanoparticles functionalized with (LLRR)3 antimicrobial peptide

The selection of effective antibiotics is becoming increasingly limited due to the emergence of bacterial resistance. Designing and developing nanoscale antibacterials is a strategy for effectively addressing the antibiotic crisis. In this work, AgNPs@AMP nanoparticles were synthesized to take advantage of the synergistic antibacterial activity of the (LLRR)3 antimicrobial peptide (AMP) and silver nanoparticles (AgNPs). Based on morphological structure characterization and biocompatibility analysis, the inhibitory properties of AgNPs@AMP on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were evaluated. The results demonstrated that AMP and AgNPs were physically bound to form AgNPs@AMP nanoparticles, which had better solution stability, improved nanomaterial properties, and overcame the hemolytic activity of AMP and the cytotoxicity of AgNPs. The inhibitory activity of AgNPs@AMP against E. coli and S. aureus was significantly higher than that of AMP and AgNPs. It was capable of disrupting the morphology and internal structure of cells, damaging the cell membrane, and inhibiting the activity of enzymes related to the material-energy metabolism of the tricarboxylic acid cycle. Compared to AMP and AgNPs, AgNPs@AMP were found to effectively inhibit the infection of mouse wounds and promote their healing. Therefore, AMP-modified AgNPs can enhance their biocompatibility and antibacterial activity, and they can be further developed as a potential antimicrobial agent.

Unveiling potentially convergent key events related to adverse outcome pathways induced by silver nanoparticles via cross-species omics-scale analysis

The adverse effects of silver nanoparticles (AgNPs) have been studied in various models. However, there has been discordance between molecular responses across the literature, attributed to methodological biases and the physicochemical variability of AgNPs. In this study, a gene pathway meta-analysis was conducted to identify convergent and divergent key events (KEs) associated with AgNPs and explore common patterns of these KEs across species. We performed a cross-species analysis of transcriptomic data from multiple studies involving various AgNPs exposure. Pathway enrichment analysis revealed a set of pathways linked to oxidative stress, apoptosis, and metabolite and lipid metabolism, which are considered potentially conserved KEs across species. Subsequently, experiments confirmed that oxidative stress responses could be early KEs in both Caenorhabditis elegans and HepG2 cells. Moreover, AgNPs preferentially impaired the mitochondria, as evidenced by mitochondrial fragmentation and dysfunction. Furthermore, disruption of amino acids, nucleotides, sulfur compounds, glycerolipids, and glycerophospholipids metabolism were in good agreement with gene pathway shreds of evidence. Our findings imply that, although there may be organism-specific responses, potentially conserved events could exist regardless of species and physicochemical factors. These results provide valuable insights into the development of adverse outcome pathways of AgNPs across species and the regulatory toxicity of AgNPs.

Nanosilver: An Old Antibacterial Agent with Great Promise in the Fight against Antibiotic Resistance

Antibiotic resistance in bacteria is a major problem worldwide that costs 55 billion USD annually for extended hospitalization, resource utilization, and additional treatment expenditures in the United States. This review examines the roles and forms of silver (e.g., bulk Ag, silver salts (AgNO3), and colloidal Ag) from antiquity to the present, and its eventual incorporation as silver nanoparticles (AgNPs) in numerous antibacterial consumer products and biomedical applications. The AgNP fabrication methods, physicochemical properties, and antibacterial mechanisms in Gram-positive and Gram-negative bacterial models are covered. The emphasis is on the problematic ESKAPE pathogens and the antibiotic-resistant pathogens of the greatest human health concern according to the World Health Organization. This review delineates the differences between each bacterial model, the role of the physicochemical properties of AgNPs in the interaction with pathogens, and the subsequent damage of AgNPs and Ag+ released by AgNPs on structural cellular components. In closing, the processes of antibiotic resistance attainment and how novel AgNP-antibiotic conjugates may synergistically reduce the growth of antibiotic-resistant pathogens are presented in light of promising examples, where antibiotic efficacy alone is decreased.

Photocatalytic Degradation, Anticancer, and Antibacterial Studies of Lysinibacillus sphaericus Biosynthesized Hybrid Metal/Semiconductor Nanocomposites

The biological synthesis of nanocomposites has become cost-effective and environmentally friendly and can achieve sustainability with high efficiency. Recently, the biological synthesis of semiconductor and metal-doped semiconductor nanocomposites with enhanced photocatalytic degradation efficiency, anticancer, and antibacterial properties has attracted considerable attention. To this end, for the first time, we biosynthesized zinc oxide (ZnO) and silver/ZnO nanocomposites (Ag/ZnO NCs) as semiconductor and metal-doped semiconductor nanocomposites, respectively, using the cell-free filtrate (CFF) of the bacterium Lysinibacillus sphaericus. The biosynthesized ZnO and Ag/ZnO NCs were characterized by various techniques, such as ultraviolet-visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The photocatalytic degradation potential of these semiconductor NPs and metal-semiconductor NCs was evaluated against thiazine dye, methylene blue (MB) degradation, under simulated solar irradiation. Ag/ZnO showed 90.4 ± 0.46% photocatalytic degradation of MB, compared to 38.18 ± 0.15% by ZnO in 120 min. The cytotoxicity of ZnO and Ag/ZnO on human cervical HeLa cancer cells was determined using an MTT assay. Both nanomaterials exhibited cytotoxicity in a concentration- and time-dependent manner on HeLa cells. The antibacterial activity was also determined against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus). Compared to ZnO, Ag/ZnO NCs showed higher antibacterial activity. Hence, the biosynthesis of semiconductor nanoparticles could be a promising strategy for developing hybrid metal/semiconductor nanomaterials for different biomedical and environmental applications.

Chemical background of silver nanoparticles interfering with mammalian copper metabolism

The rapidly increasing application of silver nanoparticles (AgNPs) boosts their release into the environment, which raises a reasonable alarm for ecologists and health specialists. This is manifested as increased research devoted to the influence of AgNPs on physiological and cellular processes in various model systems, including mammals. The topic of the present paper is the ability of silver to interfere with copper metabolism, the potential health effects of this interference, and the danger of low silver concentrations to humans. The chemical properties of ionic and nanoparticle silver, supporting the possibility of silver release by AgNPs in extracellular and intracellular compartments of mammals, are discussed. The possibility of justified use of silver for the treatment of some severe diseases, including tumors and viral infections, based on the specific molecular mechanisms of the decrease in copper status by silver ions released from AgNPs is also discussed.

Biogenic Silver Nanoparticles Produced by Soil Rare Actinomycetes and Their Significant Effect on Aspergillus-derived mycotoxins

The current investigation addressed the green synthesis of silver nanoparticles (AgNPs) using newly isolated silver-resistant rare actinomycetes, Glutamicibacter nicotianae SNPRA1 and Leucobacter aridicollis SNPRA2, and investigated their impact on the mycotoxigenic fungi Aspergillus flavus ATCC 11498 and Aspergillus ochraceus ATCC 60532. The formation of AgNPs was evidenced by the reaction's color change to brownish and the appearance of the characteristic surface plasmon resonance. The transmission electron microscopy of biogenic AgNPs produced by G. nicotianae SNPRA1 and L. aridicollis SNPRA2 (designated Gn-AgNPs and La-AgNPs, respectively) revealed the generation of monodispersed spherical nanoparticles with average sizes of 8.48 ± 1.72 nm and 9.67 ± 2.64 nm, respectively. Furthermore, the XRD patterns reflected their crystallinity and the FTIR spectra demonstrated the presence of proteins as capping agents. Both bioinspired AgNPs exhibited a remarkable inhibitory effect on the conidial germination of the investigated mycotoxigenic fungi. The bioinspired AgNPs caused an increase in DNA and protein leakage, suggesting the disruption of membrane permeability and integrity. Interestingly, the biogenic AgNPs completely inhibited the production of total aflatoxins and ochratoxin A at concentrations less than 8 μg/mL. At the same time, cytotoxicity investigations revealed the low toxicity of the biogenic AgNPs against the human skin fibroblast (HSF) cell line. Both biogenic AgNPs exhibited feasible biocompatibility with HSF cells at concentrations up to 10 μg/mL and their IC₅₀ values were 31.78 and 25.83 μg/mL for Gn-AgNPs and La-AgNPs, respectively. The present work sheds light on the antifungal prospect of the biogenic AgNPs produced by rare actinomycetes against mycotoxigenic fungi as promising candidates to combat mycotoxin formation in food chains at nontoxic doses.

[Effects of three-dimensional bioprinting antibacterial hydrogel on full-thickness skin defect wounds in rats]

Objective: To explore the effects of three-dimensional (3D) bioprinting gelatin methacrylamide (GelMA) hydrogel loaded with nano silver on full-thickness skin defect wounds in rats. Methods: The experimental research method was adopted. The morphology, particle diameter, and distribution of silver nanoparticles in nano silver solution with different mass concentrations and the pore structure of silver-containing GelMA hydrogel with different final mass fractions of GelMA were observed by scanning electron microscope and the pore size was calculated. On treatment day 1, 3, 7, and 14, the concentration of nano silver released from the hydrogel containing GelMA with final mass fraction of 15% and nano silver with final mass concentration of 10 mg/L was detected by mass spectrometer. At 24 h of culture, the diameters of inhibition zone of GelMA hydrogel containing final mass concentration of 0 (no nano silver), 25, 50, and 100 mg/L nano silver against Staphylococcus aureus and Escherichia coli were detected. Fibroblasts (Fbs) and adipose stem cells (ASCs) were isolated respectively by enzymatic digestion using the discarded prepuce after circumcision from a 5-year-old healthy boy who was treated in the Department of Urology of the Second Affiliated Hospital of Zhejiang University School of Medicine in July 2020, and the discarded fat tissue after liposuction from a 23-year-old healthy woman who was treated in the Department of Plastic Surgery of the Hospital in July 2020. The Fbs were divided into blank control group (culture medium only), 2 mg/L nano sliver group, 5 mg/L nano sliver group, 10 mg/L nano sliver group, 25 mg/L nano sliver group, and 50 mg/L nano sliver group, which were added with the corresponding final mass concentrations of nano sliver solution, respectively. At 48 h of culture, the Fb proliferation viability was detected by cell counting kit 8 method. The Fbs were divided into 0 mg/L silver-containing GelMA hydrogel group, 10 mg/L silver-containing GelMA hydrogel group, 50 mg/L silver-containing GelMA hydrogel group, and 100 mg/L silver-containing GelMA hydrogel group and then were correspondingly treated. On culture day 1, 3, and 7, the Fb proliferation viability was detected as before. The ASCs were mixed into GelMA hydrogel and divided into 3D bioprinting group and non-printing group. On culture day 1, 3, and 7, the ASC proliferation viability was detected as before and cell growth was observed by live/dead cell fluorescence staining. The sample numbers in the above experiments were all 3. Four full-thickness skin defect wounds were produced on the back of 18 male Sprague-Dawley rats aged 4 to 6 weeks. The wounds were divided into hydrogel alone group, hydrogel/nano sliver group, hydrogel scaffold/nano sliver group, and hydrogel scaffold/nano sliver/ASC group, and transplanted with the corresponding scaffolds, respectively. On post injury day (PID) 4, 7, 14, and 21, the wound healing was observed and the wound healing rate was calculated (n=6). On PID 7 and 14, histopathological changes of wounds were observed by hematoxylin eosin staining (n=6). On PID 21, collagen deposition of wounds was observed by Masson staining (n=3). Data were statistically analyzed with one-way analysis of variance, analysis of variance for repeated measurement, Bonferroni correction, and independent sample t test. Results: The sliver nano particles in nano silver solution with different mass concentrations were all round, in scattered distribution and uniform in size. The silver-containing GelMA hydrogels with different final mass fractions of GelMA all showed pore structures of different sizes and interconnections. The pore size of silver-containing GelMA hydrogel with 10% final mass fraction was significantly larger than that of silver-containing GelMA hydrogels with 15% and 20% final mass fractions (with P values both below 0.05). On treatment day 1, 3, and 7, the concentration of nano silver released from silver-containing GelMA hydrogel in vitro showed a relatively flat trend. On treatment day 14, the concentration of released nano silver in vitro increased rapidly. At 24 h of culture, the diameters of inhibition zone of GelMA hydrogel containing 0, 25, 50, and 100 mg/L nano silver against Staphylococcus aureus and Escherichia coli were 0, 0, 0.7, and 2.1 mm and 0, 1.4, 3.2, and 3.3 mm, respectively. At 48 h of culture, the proliferation activity of Fbs in 2 mg/L nano silver group and 5 mg/L nano silver group was both significantly higher than that in blank control group (P<0.05), and the proliferation activity of Fbs in 10 mg/L nano silver group, 25 mg/L nano silver group, and 50 mg/L nano silver group was all significantly lower than that in blank control group (P<0.05). Compared with the that of Fbs in 0 mg/L silver-containing GelMA hydrogel group, the proliferation activity of Fbs in 50 mg/L silver-containing GelMA hydrogel group and 100 mg/L silver-containing GelMA hydrogel group was all significantly decreased on culture day 1 (P<0.05); the proliferation activity of Fbs in 50 mg/L silver-containing GelMA hydrogel group was significantly increased (P<0.05), while the proliferation activity of Fbs in 100 mg/L silver-containing GelMA hydrogel group was significantly decreased on culture day 3 (P<0.05); the proliferation activity of Fbs in 100 mg/L silver-containing GelMA hydrogel group was significantly decreased on culture day 7 (P<0.05). The proliferation activity of ASCs in 3D bioprinting group show no statistically significant differences to that in non-printing group on culture day 1 (P>0.05). The proliferation activity of ASCs in 3D bioprinting group was significantly higher than that in non-printing group on culture day 3 and 7 (with t values of 21.50 and 12.95, respectively, P<0.05). On culture day 1, the number of dead ASCs in 3D bioprinting group was slightly more than that in non-printing group. On culture day 3 and 5, the majority of ASCs in 3D bioprinting group and non-printing group were living cells. On PID 4, the wounds of rats in hydrogel alone group and hydrogel/nano sliver group had more exudation, and the wounds of rats in hydrogel scaffold/nano sliver group and hydrogel scaffold/nano sliver/ASC group were dry without obvious signs of infection. On PID 7, there was still a small amount of exudation on the wounds of rats in hydrogel alone group and hydrogel/nano sliver group, while the wounds of rats in hydrogel scaffold/nano sliver group and hydrogel scaffold/nano sliver/ASC group were dry and scabbed. On PID 14, the hydrogels on the wound surface of rats in the four groups all fell off. On PID 21, a small area of wounds remained unhealed in hydrogel alone group. On PID 4 and 7, the wound healing rates of rats in hydrogel scaffold/nano sliver/ASC group were significantly higher than those of the other three groups (P<0.05). On PID 14, the wound healing rate of rats in hydrogel scaffold/nano sliver/ASC group was significantly higher than the wound healing rates in hydrogel alone group and hydrogel/nano sliver group (all P<0.05). On PID 21, the wound healing rate of rats in hydrogel alone group was significantly lower than that in hydrogel scaffold/nano sliver/ASC group (P<0.05). On PID 7, the hydrogels on the wound surface of rats in the four groups remained in place; on PID 14, the hydrogel in hydrogel alone group was separated from the wounds of rats, while some hydrogels still existed in the new tissue of the wounds of rats in the other three groups. On PID 21, the collagen arrangement in the wounds of rats in hydrogel alone group was out of order, while the collagen arrangement in the wounds of rats in hydrogel/nano sliver group, and hydrogel scaffold/nano sliver/ASC group was relatively orderly. Conclusions: Silver-containing GelMA hydrogel has good biocompatibility and antibacterial properties. Its three-dimensional bioprinted double-layer structure can better integrate with new formed tissue in the full-thickness skin defect wounds in rats and promote wound healing.

Silver Is Not Equal to Silver: Synthesis and Evaluation of Silver Nanoparticles with Low Biological Activity, and Their Incorporation into C12Alanine-Based Hydrogel

A new type of silver nanoparticles (AgNPs) was prepared and comprehensively studied. Scanning electron microscopy (SEM) and dynamic light scattering (DLS) analyses indicated that 24 nm AgNPs with narrow size distribution were obtained while Z-potential confirms their good stability. The composites of the obtained AgNPs with nontoxic-nature-inspired hydrogel were formed upon cooling of the aqueous solution AgNPs and C₁₂Ala. The thermal gravimetric analysis (TGA) and the differential scanning calorimetry (DSC) do not show significant shifts in the characteristic temperature peaks for pure and silver-enriched gels, which indicates that AgNPs do not strongly interact with C₁₂Ala fibers, which was also confirmed by SEM. Both AgNPs alone and in the assembly with the gelator C₁₂Ala were almost biologically passive against bacteria, fungus, cancer, and nontumor human cells, as well as zebra-fish embryos. These studies proved that the new inactive AgNPs-doped hydrogels have potential for the application in therapy as drug delivery media.

Clindamycin-Loaded Halloysite Nanotubes as the Antibacterial Component of Composite Hydrogel for Bone Repair

A new drug delivery system consisting of clindamycin phosphate entrapped in acid-etched halloysite nanotubes was successfully prepared and characterized. It was then used as an antibacterial component of the multicomponent hydrogel designed as a material for bone regeneration. First, halloysite (HNT) was etched and clindamycin phosphate (CP) was entrapped in both raw and modified nanotubes, resulting in HNT-CP and EHNT-CP systems. They were characterized using SEM, TEM, TGA and FTIR; the entrapment efficiency and release of CP from both systems were also studied. EHNT-CP was then used as an antibacterial component of the two hydrogels composed of alginate, collagen and β-TCP. The hydrogels were prepared using different crosslinking procedures but had the same composition. The morphology, porosity, degradation rate, CP release profile, cytocompatibility, antibacterial activity and ability to induce biomineralization were studied for both materials. The hydrogel obtained by a chemical crosslinking with EDC followed by the physical crosslinking with calcium ions had better properties and was shown to have potential as a bone repair material.

Silver nanoparticles instigate physiological, genotoxicity, and ultrastructural anomalies in midgut tissues of beetles

Silver nanoparticles (AgNPs) have long been materials of great interest in numerous fields; however, there is escalating alarm over their toxicity to public health since exposure to these particles is inevitable. This study sheds light on the deleterious impacts of AgNPs on the midgut tissues of beetles (Blaps polychresta) collected from Egypt as a biological model. The investigations were conducted on the beetles administered with a sublethal dose of AgNPs (0.03 mg/g body weight) after 30 days. Oxidative stress parameters and antioxidant enzyme activities were assessed, which exposed critical disruption in the antioxidant defense system of treated beetles. Remarkably, metallothionein (MT) gene expression was significantly increased, while reduced glutathione (GSH) level was notably decreased in midgut tissues subjected to AgNPs. These findings manifestly imply the presence of overproduction in terms of reactive oxygen species (ROS) inside the cells. Additionally, DNA impairment and apoptosis of midgut cells were appraised employing comet and flow cytometry analyses, respectively. The comet results revealed a significant increase in comet cells for the AgNPs treated beetles compared with the control group. Furthermore, the apoptosis results demonstrated a substantial diminution in viable cells with significant growth in apoptotic cells in midgut cells exposed to AgNPs, manifesting their striking correlation with comet and biochemical findings. Noticeably, the histopathological and ultrastructural inspections revealed substantial aberrations in the midgut tissues in the AgNPs treated group, substantiating the previous results. As far as we know, no research has been found that surveyed how the AgNPs at low doses affect the midgut tissues of beetles. Overall, these findings evince the aberrant influences of AgNPs on living organisms.

3D-Printed Polymer-Infiltrated Ceramic Network with Antibacterial Biobased Silver Nanoparticles

This work aimed at the antimicrobial functionalization of 3D-printed polymer-infiltrated biomimetic ceramic networks (PICN). The antimicrobial properties of the polymer-ceramic composites were achieved by coating them with human- and environmentally safe silver nanoparticles trapped in a phenolated lignin matrix (Ag@PL NPs). Lignin was enzymatically phenolated and used as a biobased reducing agent to obtain stable Ag@PL NPs, which were then formulated in a silane (γ-MPS) solution and deposited to the PICN surface. The presence of the NPs and their proper attachment to the surface were analyzed with spectroscopic methods (FTIR and Raman) and X-ray photoelectron spectroscopy (XPS). Homogeneous distribution of 13.4 ± 3.2 nm NPs was observed in the transmission electron microscopy (TEM) images. The functionalized samples were tested against Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria, validating their antimicrobial efficiency in 24 h. The bacterial reduction of S. aureus was 90% in comparison with the pristine surface of PICN. To confirm that the Ag-functionalized PICN scaffold is a safe material to be used in the biomedical field, its biocompatibility was demonstrated with human fibroblast (BJ-5ta) and keratinocyte (HaCaT) cells, which was higher than 80% in both cell lines.

Protective effects of silver nanoparticles in isoproterenol-induced myocardial infarction in rats

Background

Silver nanoparticles (AgNPs) are widely used in the medical field, including cardiovascular. However, limited research has investigated the effect of AgNPs on the protection of myocardial infarction (MI).

Objectives

Isoproterenol (Iso)-induced MI and the cardiac protection offered by AgNPs were investigated in the present study. Additionally, we characterized the profile of Ag in the form of nanoparticles.

Methods

Twenty-four male Wistar rats were randomly divided into four groups as follows: normal, Iso, Iso + AgNO3, and Iso + AgNP groups. AgNPs and silver ion (AgNO3) were administered intraperitoneally at 2.5 mg/kg BW for 14 days. Iso induction was performed using two doses of 85 mg/kg BW given subcutaneously on days 13 and 14. Blood and cardiac tissue samples were taken 24 h after the last dose of Iso and checked for Creatine Kinase-MB (CK-MB), lactate dehydrogenase in plasma along with oxidative stress parameters, mitochondria biogenesis markers, and inflammation representative genes in cardiac tissue. Additionally, we analyzed the histopathological features in cardiac tissue.

Results

The silver was confirmed in the form of nanoparticles by its size at intervals of 8.72-37.84 nm. Both AgNO3 and AgNPs showed similar cardioprotective effects, as shown by the decrease in biochemical markers of cardiac toxicity, namely, CK-MB. Additionally, AgNPs group have better efficacy compared with AgNO3 group in ameliorating Iso-mediated oxidative stress production, as evidenced by the significant decrease in malondialdehyde level and increased superoxide dismutase activity (P < 0.0001 and P < 0.01, respectively) in cardiac tissue compared with the Iso group. Mechanistically, AgNPs, but not AgNO3, enhanced the expression levels of mitochondrial transcription factor A and peroxisome proliferator-activated receptor-gamma coactivator 1-alpha in post-MI heart and reduced the protein expression of nuclear factor-kappa B (NF-κB) assessed by western blot analysis. Furthermore, these results were confirmed with the histopathological evaluation of cardiac tissue. Nevertheless, pretreatment with either AgNO3 or AgNPs improved the aspartate aminotransferase level.

Conclusion

These results suggested that AgNPs have more superior cardioprotective effect compared with AgNO3 against Iso-induced MI, at least in part through amelioration of NF-κB expression level induced by oxidative stress overproduction.