Unique Cellular Interaction of Silver Nanoparticles: Size-Dependent Generation of Reactive Oxygen Species

Rethinking the application of nanoparticles in women's reproductive health and assisted reproduction

Nanoparticles and nanotechnology may present opportunities to revolutionize the prevention, treatment and diagnosis of a range of reproductive health conditions in women. These technologies are also used to improve outcomes of assisted reproductive technology. We highlight a range of these potential clinical uses of nanoparticles for polycystic ovary syndrome, endometriosis, uterine fibroids and sexually transmitted infections, considering in vitro and in vivo studies along with clinical trials. In addition, we discuss applications of nanoparticles in assisted reproductive technology, including sperm loading, gamete and embryo preservation and preventing preterm birth. Finally, we present some of the concerns associated with the medical use of nanoparticles, identifying routes for further exploration before nanoparticles can be applied to women's reproductive health in the clinic.

Tunable Release of Ions from Graphene Oxide Laminates for Sustained Antibacterial Activity in a Biomimetic Environment

Silver has long been recognized for its potent antimicrobial properties, but achieving a slow and longer-term delivery of silver ions presents significant challenges. Previous efforts to control silver ion dosages have struggled to sustain release for extended periods in biomimetic environments, especially in the presence of complex proteins. This challenge is underscored by the absence of technology for sustaining antimicrobial activity, especially in the context of orthopedic implants where long-term efficacy, extending beyond 7 days, is essential. In this study, the tunable, slow, and longer-term release of silver ions from the two-dimensional (2D) nanocapillaries of graphene oxide (GO) laminates incorporated with silver ions (Ag-GO) for antimicrobial applications are successfully demonstrated. To closely mimic a physiologically relevant serum-based environment, a novel in vitro study model using 100% fetal bovine serum (FBS) is introduced as the test medium for microbiology, biocompatibility, and bioactivity studies. To emulate fluid circulation in a physiological environment, the in vitro studies are challenged with serum exchange protocols on different days. The findings show that the Ag-GO coating can sustainably release silver ions at a minimum dosage of 10 µg cm-2 day-1, providing an effective and sustained antimicrobial barrier for over ten days.

Synthesis of bio-stabilized silver nanoparticles using Roccella montagnei, their anticandidal capacities & potential to inhibit the virulence factors in fluconazole-resistant Candida albicans

Candida species is the causative agent in approximately 80% of invasive mycoses and drug-resistant Candida albicans is among the four strains of 'critical priority group' framed by WHO. Lichens are endowed with some rare phytochemicals and a plethora of therapeutics viz. antifungal capacities of Roccella montagnei. Biosynthesis of silver nanoparticles (AgNPs) using lichen could offer an eco-friendly, and cost-effective alternative against emerging 'microbial resistance.' Therefore, the objective was to biosynthesize silver nanoparticles (Rm-AgNPs) using a Hydro-alcoholic (1:1) extract of R. montagnei to develop a potent anticandidal agent against Fluconazole-resistant C. albicans NBC099. UV-Spectroscopy identified AgNPs specific-peak of Rm-AgNPs at 420-440 nm and FTIR revealed the presence of amines, alcohol, aromatic compounds, and acids. SEM and TEM analysis indicated that Rm-AgNPs are spherical shaped with a size range of 10-50 nm. Zetasizer analysis indicated that particles are highly stable and have a mean hydrodynamic diameter of 116 nm with a zeta potential charge of - 41 mV. XRD analysis suggested face centered cubic crystal lattice structure. Results indicated that Rm-AgNPs strongly inhibited the growth of NBC099 at a minimum inhibitory concentration (IC50) of ≤ 15 µg. C. albicans culture treated with Rm-AgNPs at concentrations below IC50, down-regulates the production of different virulence factors in NBC099, viz. hyphal formation (> 85%), biofilms production (> 80%), phospholipase, esterase, proteinase activity. The apoptosis assay demonstrated the Rm-AgNPs induced apoptosis in NBC099 cells via oxidative stress. Interestingly, Rm-AgNPs showed negligible cytotoxicity (< 6%) in murine RAW 246.7 macrophage cells at a concentration above 15 µg/mL. Therefore, Rm-AgNPs have been offered as an anti-candida alternative that can be utilized to improve the efficacy of already available medications.

Silver nanoparticles in plant health: Physiological response to phytotoxicity and oxidative stress

Silver nanoparticles (AgNPs) have gained significant attention in various fields due to their unique properties, but their release into the environment has raised concerns about their environmental and biological impacts. Silver nanoparticles can enter plants following their exposure to roots or via stomata following foliar exposure. Upon penetrating the plant cells, AgNPs interact with cellular components and alter physiological and biochemical processes. One of the key concerns associated with plant exposure to AgNPs is the potential of these materials to induce oxidative stress. Silver nanoparticles can also suppress plant growth and development by disrupting essential plant physiological processes, such as photosynthesis, nutrient uptake, water transport, and hormonal regulation. In crop plants, these disruptions may, in turn, affect the productivity and quality of the harvested components and therefore represent a potential threat to agricultural productivity and ecosystem stability. Understanding the phytotoxic effects of AgNPs is crucial for assessing their environmental implications and guiding the development of safe nanomaterials. By delving into the phytotoxic effects of AgNPs, this review contributes to the existing knowledge regarding their environmental risks and promotes the advancement of sustainable nanotechnological practices.

Tripeptides Ghk and GhkCu-modified silver nanoparticles for enhanced antibacterial and wound healing activities

Bacterial skin infections represent a major healthcare concern that can delay healing and threaten human health. Silver nanoparticles (AgNPs) have been widely used for antimicrobial purposes; however, their high toxicity limits their applications. Therefore, there is an urgent need to develop simple and efficient therapeutic approaches for treating bacterial infections and promoting wound healing. Here, novel tripeptide (Ghk and GhkCu)-modified AgNPs were developed and subsequently evaluated their antibacterial efficacy against four pathogenic bacterial isolates, cytotoxic properties, and therapeutic effects as a topical treatment for infected wounds. Spherical GhkAgNPs and GhkCuAgNPs with average sizes of 45.92 nm and 56.82 nm exhibited potential antibacterial activity, with a MIC concentration of 8 μg/ml against S. aureus and E. coli. Both AgNPs showed superior bactericidal effects against S. aureus, with complete inhibition after 7 days of treatment. Cytotoxicity assays revealed IC50 (half maximal inhibitory concentrations) values ranging from 6.75 to 6.99 µg/ml in L929 cells. GhkAgNPs displayed accelerated cell migration and facilitated healing up to 92% after 12 h. Furthermore, topical applications of GhkAgNPs and GhkCuAgNPs to S. aureus-infected wounds demonstrated enhanced in vivo wound healing efficacy compared to control groups, as evidenced by increased regenerated epidermal thickness, improved collagen deposition, and downregulation of TNF-α expression. Hence concluded that these novel tripeptides Ghk and GhkCu-modified AgNPs exhibited potent antibacterial effects and significantly promoted wound healing properties.

In Vitro Effects of Zirconia Nanoparticles: Uptake, Genotoxicity, and Mutagenicity in V-79 cells

Zirconia nanoparticles are used in various industrial and biomedical applications such as dental implants, thermal barrier sprays, and fuel cells. The interaction of nanoparticles with the environment and humans is inevitable. Despite the enormous application potential of these nanoparticles, there are still some gaps in the literature regarding potential toxicological mechanisms and the genotoxicity of zirconia nanoparticles. The lung is one of the main exposure routes to nanomaterials; therefore, the present study was designed to determine the genotoxic and mutagenic effect of zirconia NPs in V-79 lung cells. Zirconia nanoparticles showed significant internalization in cells at 100 μg/mL and 150 μg/mL concentrations. Zirconia nanoparticles showed low cytotoxicity and were found to generate ROS in V-79 cells. In alkaline comet assay, zirconia nanoparticles (10 μg/mL, 50 μg/mL, and 100 μg/mL) exposed cells exhibited significant DNA strand breaks, while the neutral comet assay, which was used for double-strand break assessment, only revealed significant damage at 100 μg/mL. Chromosomal aberration induced by zirconia nanoparticles mainly resulted in the generation of gaps, few fragments, and breaks which signifies the low clastogenic activity of these nanoparticles in the V-79 cell line. In MN assay, zirconia nanoparticles resulted in no significant micronuclei induction at any given concentration. In the HPRT mutation assay, the particle shows a dose-dependent increase in the mutant frequency. It is evident from the result that zirconia nanoparticles cause dose-dependent cytotoxicity and genotoxicity, but still, more studies are needed to evaluate the clastogenic potential and the possible mechanism involved.

Unveiling the inhibition of chlortetracycline photodegradation and the increase of toxicity when coexisting with silver nanoparticles

Silver nanoparticles (AgNPs) and antibiotics inevitably co-exist in water environment. Nonetheless, little is known regarding the interactions between AgNPs and antibiotics or the effects of AgNPs on environmental behavior of antibiotics, particularly on sunlight-driven transformation. In the present work, we found that AgNPs obviously inhibit the photochemical decay of chlortetracycline (CTC), and CTC boosts the dissolution of AgNPs. With the help of electron paramagnetic resonance (EPR) and quenching experiment, we ascertained that these results originated from the competition between AgNPs against CTC for capturing 1O2 generated from CTC photosensitization. 1O2 reacting with CTC contributed mostly to CTC photodegradation, while 1O2 as well reacting with AgNPs leads to release of Ag+. When compared to reaction of 1O2 with CTC, 1O2 is prone to react with AgNPs, based on lower Gibbs free energy of AgNPs reacting with 1O2. Therefore, upon CTC co-existing with AgNPs, the release of Ag+ was accelerated and the photodegradation of CTC was inhibited obviously. Furthermore, the accelerated release of Ag+ significantly increased their toxicity toward E. coli cells under simulate sunlight irradiation. Overall, the findings demonstrate how AgNPs interact with CTC and how these interactions affect the environmental behaviors of CTC or AgNPs, allowing more accurate assessments of the risk to ecosystems posed by AgNPs coexisting with antibiotics.

Silver nanoparticle ecotoxicity and phytoremediation: a critical review of current research and future prospects

Silver nanoparticles (AgNPs) are widely used in various industries, including textiles, electronics, and biomedical fields, due to their unique optical, electronic, and antimicrobial properties. However, the extensive use of AgNPs has raised concerns about their potential ecotoxicity and adverse effects on the environment. AgNPs can enter the environment through different pathways, such as wastewater, surface runoff, and soil application and can interact with living organisms through adsorption, ingestion, and accumulation, causing toxicity and harm. The small size, high surface area-to-volume ratio, and ability to generate reactive oxygen species (ROS) make AgNPs particularly toxic. Various bioremediation strategies, such as phytoremediation, have been proposed to mitigate the toxic effects of AgNPs and minimize their impact on the environment. Further research is needed to improve these strategies and ensure their safety and efficacy in different environmental settings.

Enhancing antimicrobial activity and reducing cytotoxicity of silver nanoparticles through gelatin nanoparticles

Aim: To develop a novel stabilizing agent for silver nanoparticles (AgNPs) with the aim of enhancing its antibacterial efficacy against wound associated pathogens while mitigating their cytotoxic effect on human cells. Materials & methods: In this study, monodispersed gelatin nanoparticles were synthesized to stabilize AgNPs. The stability, antibacterial activity and biocompatibility of the gelatin-stabilized AgNPs (Gel-AgNPs) were compared with citrate-stabilized AgNPs (citrate-AgNPs) or silver ions. Results & conclusion: Gelatin-stabilized AgNPs showed significantly better antibacterial activities compared with citrate-stabilized AgNPs against both Gram-positive and Gram-negative bacteria. These Gel-AgNPs showed significantly lower cytotoxicity to human dermal fibroblasts compared with Ag+. These findings provided the first evidence substantiating a novel functionality of gelatin nanoparticles in both stabilizing and enhancing the activity of AgNPs.

Local and systemic adverse effects of nanoparticles incorporated in dental materials- a critical review

Introduction

Nanotechnology is the science and engineering of nanoparticles whose dimensions range from 1 to 100 nm. Nanoparticles have special characteristics like increased surface area, high reactivity, and enhanced mechanical, thermal, and optical properties that make them attractive for use in dental applications. However, the use of nanoparticles in dental materials can have toxic effects on the human body. The objective of this paper is to discuss the toxic effects of various nanoparticles in dental materials, their adverse effect on human health, and measures to overcome such effects.

Objectives

Nanoparticles are used in the diagnosis, prevention, and treatment of oral diseases like dental caries, pulpo periodontal lesions, oral cancer, denture stomatitis, and candidiasis. Exposure to nanoparticles may occur to the dental professional, and the patient during procedures like restoration, finishing, and polishing. Such exposure to nanoparticles through inhalation, and ingestion causes toxic effects in the lungs, skin, brain, liver, and kidney. Proper risk assessment methods and preventive measures may help reduce these toxic effects to some extent.

Significance

Toxic effects of nanoparticles that are released during dental procedures, their route of exposure, and the concentration at which nanoparticles can induce toxic effects on the human body are discussed in detail in this review. The paper also aims to create awareness among dental professionals, students, and patients regarding nanoparticle exposure and its adverse effects, and methods to prevent and overcome these effects. Currently, it is ignored or taken lightly by the stakeholders and this review may throw light.

Effects of silver nanoparticles and various forms of silver on nitrogen removal by the denitrifier Pseudomonas stutzeri and their toxicity mechanisms

Silver nanoparticles (AgNPs) are widely used in daily life and industry because of their excellent antibacterial properties. AgNPs can exist in wastewater in various forms, such as Ag+, Ag2SO4, Ag2CO3, Ag2S, Ag2O, and AgCl. To assess the potential environmental risk of AgNPs and various forms of Ag, their toxic effects were investigated using the common denitrifier species Pseudomonas stutzeri (P. stutzeri). The inhibitory effect of AgNPs and various forms of Ag on P. stutzeri growth and its denitrification performance occurred in a concentration-dependent manner. The denitrification efficiency of P. stutzeri decreased from 95%∼97% to 89∼95%, 74∼95%, and 56∼85% under low, medium, and high exposure doses, respectively, of AgNPs and various forms of Ag. The changes in cell membrane morphology and increases in lactate dehydrogenase (LDH) release indicated that AgNPs and various forms of Ag damaged the cell membrane of P. stutzeri. Oxidative stress caused by excessive accumulation of reactive oxygen species (ROS) increased superoxide dismutase (SOD) and catalase (CAT) activities and decreased glutathione (GSH) levels. Overall, this study will help elucidate the impact of AgNPs and their transformation products on nitrogen removal efficiency in wastewater biological treatment systems.

Quantitative biodistribution of nanoparticles in plants with lanthanide complexes

The inefficient distribution of fertilizers, nutrients, and pesticides on crops is a major challenge in modern agriculture that leads to reduced productivity and environmental pollution. Nanoformulation of agrochemicals is an attractive approach to enable the selective delivery of agents into specific plant organs, their release in those tissues, and improve their efficiency. Already commercialized nanofertilizers utilize the physiochemical properties of metal nanoparticles such as size, charge, and the metal core to overcome biological barriers in plants to reach their target sites. Despite their wide application in human diseases, lipid nanoparticles are rarely used in agricultural applications and a systematic screening approach to identifying efficacious formulations has not been reported. Here, we developed a quantitative metal-encoded platform to determine the biodistribution of different lipid nanoparticles in plant tissues. In this platform lanthanide metal complexes were encapsulated into four types of lipid nanoparticles. Our approach was able to successfully quantify payload accumulation for all the lipid formulations across the roots, stem, and leaf of the plant. Lanthanide levels were 20- to 57-fold higher in the leaf and 100- to 10,000-fold higher in the stem for the nanoparticle encapsulated lanthanide complexes compared to the unencapsulated, free lanthanide complex. This system will facilitate the discovery of nanoparticles as delivery carriers for agrochemicals and plant tissue-targeting products.

Antibacterial, antibiofilm, and antivirulence effects of nanoparticles synthesized from Colletotrichum gloeosporioides in pathogenic E.coli

Antimicrobial resistance is a global problem and antibiotics are becoming ineffective due to the resistance developed by bacteria. In this current research, silver nanoparticles were synthesized from aqueous extract of endophytic fungi Colletotrichum gloeosporioides (CgAgNPs) and characterized by various methods. CgAgNPs efficacy was analyzed by performing antimicrobial assays in Escherichia coli ATCC 25922 and antibiotic resistant pathogenic strains. Upon treatment with CgAgNPs biofilm formation was reduced in all E.coli strains. In vitro cytotoxicity assays revealed that CgAgNPs were able to increase the membrane permeability and induced leakage of sugars and proteins. CgAgNPs induced oxidative stress in E. coli strains led to lipid peroxidation and release of malonaldehyde. The CgAgNPs were able to modulate the anti-oxidant system of cells hence there was a reduction in Glutathione reductase, Catalase and Superoxide dismutase enzymes activities. Analysis of expression of gene encoding CTX-M-15 showed the down regulation upon treatment with ampicillin and CgAgNPs. Overall, the results suggest that CgAgNPs control growth, biofilm formation in E. coli through induction of oxidative stress, interference with antioxidant enzymes, cell content leakage and finally downregulating the virulence gene by interfering with transcription and translation in E. coli. In future, CgAgNPs can be incorporated in formulations to break antibiotic resistance in antibiotic resistant pathogenic E. coli.

Polysaccharides and proteins based bionanocomposites as smart packaging materials: From fabrication to food packaging applications a review

Food industry is the biggest and rapidly growing industries all over the world. This sector consumes around 40 % of the total plastic produced worldwide as packaging material. The conventional packaging material is mainly petrochemical based. However, these petrochemical based materials impose serious concerns towards environment after its disposal as they are nondegradable. Thus, in search of an appropriate replacement for conventional plastics, biopolymers such as polysaccharides (starch, cellulose, chitosan, natural gums, etc.), proteins (gelatin, collagen, soy protein, etc.), and fatty acids find as an option but again limited by its inherent properties. Attention on the initiatives towards the development of more sustainable, useful, and biodegradable packaging materials, leading the way towards a new and revolutionary green era in the food sector. Eco-friendly packaging materials are now growing dramatically, at a pace of about 10-20 % annually. The recombination of biopolymers and nanomaterials through intercalation composite technology at the nanoscale demonstrated some mesmerizing characteristics pertaining to both biopolymer and nanomaterials such as rigidity, thermal stability, sensing and bioactive property inherent to nanomaterials as well as biopolymers properties such as flexibility, processability and biodegradability. The dramatic increase of scientific research in the last one decade in the area of bionanocomposites in food packaging had reflected its potential as a much-required and important alternative to conventional petroleum-based material. This review presents a comprehensive overview on the importance and recent advances in the field of bionanocomposite and its application in food packaging. Different methods for the fabrication of bionanocomposite are also discussed briefly. Finally, a clear perspective and future prospects of bionanocomposites in food packaging were presented.

Metal Ion-Doped Hydroxyapatite-Based Materials for Bone Defect Restoration

Hydroxyapatite (HA)-based materials are widely used in the bone defect restoration field due to their stable physical properties, good biocompatibility, and bone induction potential. To further improve their performance with extra functions such as antibacterial activity, various kinds of metal ion-doped HA-based materials have been proposed and synthesized. This paper offered a comprehensive review of metal ion-doped HA-based materials for bone defect restoration based on the introduction of the physicochemical characteristics of HA followed by the synthesis methods, properties, and applications of different kinds of metal ion (Ag+, Zn2+, Mg2+, Sr2+, Sm3+, and Ce3+)-doped HA-based materials. In addition, the underlying challenges for bone defect restoration using these materials and potential solutions were discussed.

In Vitro Efficacy of Isobutyl Cyanoacrylate Nanoparticles against Fish Bacterial Pathogens and Selection Preference by Rainbow Trout (Oncorhynchus mykiss)

The upsurge in havoc being wreaked by antibiotic-resistant bacteria has led to an urgent need for efficacious alternatives to antibiotics. This study assessed the antibacterial efficacy of two isobutyl cyanoacrylate nanoparticles (iBCA-NPs), D6O and NP30, against major bacterial pathogens of fish. In vivo tests on rainbow trout were preceded by in vitro tests of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). NP30 exhibited higher efficacy than D60, but both iBCA-NPs demonstrated dose-dependent and species-specific in vitro antibacterial properties against the bacterial isolates. Generally, Gram-negative bacteria were more resistant to the iBCA-NPs. Streptococcus iniae, Tenacibaculum maritimum, and Photobacterium damselae were particularly sensitive to both iBCA-NPs. Administered to rainbow trout at 3571.4 mg (iBCA-NP)/kg feed, the iBCA-NPs produced a relative gain rate and survival rates comparable to the control (p > 0.05). The condition factor and the hepatosomatic and viscerosomatic indices of fish were indifferentiable (p > 0.05) between the iBCA-NP groups and the control. The iBCA-NPs caused no alteration in stress, oxidative stress (superoxide dismutase, SOD), plasma complement titer, or lysozyme activity. This study presents the first report of antibacterial activity of iBCA-NPs against Gram-negative bacteria. The results of this study suggest that D60 and NP30 may contribute to reducing the amounts of antibiotics and chemotherapeutic agents used in aquaculture.

Formulation and Comprehensive Evaluation of Biohybrid Hydrogel Membranes Containing Doxycycline or Silver Nanoparticles

Complicated wounds often require specialized medical treatments, and hydrogels have emerged as a popular choice for wound dressings in such cases due to their unique properties and the ability to incorporate and release therapeutic agents. Our focus was to develop and characterize a new optimized formula for biohybrid hydrogel membranes, which combine natural and synthetic polymers, bioactive natural compounds, like collagen and hyaluronic acid, and pharmacologically active substances (doxycycline or npAg). Dynamic (oscillatory) rheometry confirmed the strong gel-like properties of the obtained hydrogel membranes. Samples containing low-dose DOXY showed a swelling index of 285.68 ± 6.99%, a degradation rate of 71.6 ± 0.91% at 20 h, and achieved a cumulative drug release of approximately 90% at pH 7.4 and 80% at pH 8.3 within 12 h. The addition of npAg influenced the physical properties of the hydrogel membranes. Furthermore, the samples containing DOXY demonstrated exceptional antimicrobial efficacy against seven selected bacterial strains commonly associated with wound infections and complications. Biocompatibility assessments revealed that the samples exhibited over 80% cell viability. However, the addition of smaller-sized nanoparticles led to decreased cellular viability. The obtained biohybrid hydrogel membranes show favorable properties that render them suitable for application as wound dressings.

Cysteine-Silver-Polymer Systems for the Preparation of Hydrogels and Films with Potential Applications in Regenerative Medicine

Herein, the problem concerning the poorer mechanical properties of gels based on low molecular weight gelators (LMWGs)-L-cysteine and silver nitrate-was solved by the addition of various polymers-polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP) and polyethylene glycol (PEG)-to the initial cysteine-silver sol (CSS). The physicochemical methods of analysis-viscosimetry, UV spectroscopy, DLS, and SEM-identified that cysteine-silver hydrogels (CSG) based on PVA possess the best rheological properties and porous microstructure (the average pore size is 2-10 µm) compared to gels without the polymer or with PVP or PEG. Such gels are able to form cysteine-silver cryogels (CSC) and then porous cysteine-silver films (CSF) with an average pore size of 10-20 µm and good mechanical, swelling, and adhesion to skin characteristics as long as the structure of CSS particles remains stable. In vitro experiments have shown that hydrogels are non-toxic to normal human fibroblast cells. The obtained materials could potentially be applied to regenerative medicine.

Biocidal and synergistic effect of three types of biologically synthesised silver/silver chloride nanoparticles

Three types of silver/silver chloride nanoparticles were obtained by green synthesis from three types of microbial biomass. Their biocidal capacity was tested against six microorganisms. Two filamentous fungi were used that had previously demonstrated the ability to synthesise nanoparticles, Penicillium sp. 8L2 and Botryosphaeria rhodina MAMB-05. Also, the synthesis capacity of a yeast, Rhodotorula mucilaginosa 1S1, was evaluated. The original protocols underwent slight modifications. At the same time, the fractional inhibitory concentration was obtained. The interaction between specific antibiotics and the nanoparticles that showed the greatest biocidal capacity came from Penicillium sp.8L2, and it was studied further. All nanoparticles were characterised by UV-vis spectrophotometry and transmission electron microscopy (TEM). Also, their size distribution was analysed, which was in the range of 4 to 34 nm. The biocidal capacity of the nanoparticles for a group of bacteria and fungi was studied, presenting very low values in the range of 2.5-10 µg/mL for bacteria and 4-256 µg/mL for fungi. The interactions between the nanoparticles synthesised by Penicillium sp. 8L2 and a group of specific antibiotics for the tested microorganisms were also studied, proving that there was a synergistic interaction with vancomycin and ciprofloxacin and Staphylococcus epidermidis CECT 4183 and Escherichia coli CECT 101 bacteria, respectively.

Silver Nanoparticle Synthesis in Glycerol by Low-Pressure Plasma-Driven Electrolysis: The Roles of Free Electrons and Photons

Low-temperature plasmas in and in contact with liquids have emerged as a catalyst-free approach for the selective, electrode-free, and green synthesis of novel materials. For the synthesis of nanomaterials, short-lived solvated electrons have been proposed to be the critical reducing species, while the role of ultraviolet (UV) photons from plasma is less explored. Here, we demonstrate that UV radiation contributes ∼70% of the integral plasma effect in synthesizing silver (Ag) nanoparticles within a glycerol solution. We suggest that the UV radiation causes C-H bond cleavage of the glycerol molecules, with an experimentally and theoretically determined threshold photon energy of only 5 eV. The photon-induced dissociation leads to the formation of glycerol fragmentation radicals, causing the reduction of Ag+ ions to Ag neutrals, enabling nanoparticle formation in the liquid phase.

Insight interactions of engineered nanoparticles with aquatic higher plants for phytoaccumulation, phytotoxicity, and phytoremediation applications: A review

With the growing age of human civilization, industrialization has paced up equally which is followed by the innovation of newer concepts of science and technology. One such example is the invention of engineered nanoparticles and their flagrant use in widespread applications. While ENPs serve their intended purposes, they also disrupt the ecological balance by contaminating pristine aquatic ecosystems. This review encompasses a comprehensive discussion about the potent toxicity of ENPs on aquatic ecosystems, with a particular focus on their impact on aquatic higher plants. The discussion extends to elucidating the fate of ENPs upon release into aquatic environments, covering aspects ranging from morphological and physiological effects to molecular-level phytotoxicity. Furthermore, this level of toxicity has been correlated with the determination of competent plants for the phytoremediation process towards the mitigation of this ecological stress. However, this review further illustrates the path of future research which is yet to be explored. Determination of the genotoxicity level of aquatic higher plants could explain the entire process comprehensively. Moreover, to make it suitable to be used in natural ecosystems phytoremediation potential of co-existing plant species along with the presence of different ENPs need to be evaluated. This literature will undoubtedly offer readers a comprehensive understanding of the stress induced by the irresponsible release of engineered nanoparticles (ENP) into aquatic environments, along with insights into the resilience characteristics of these pristine ecosystems.

Multiplex Quantification of Exosomes via Multiple Types of Nanobeads Labeling Combined with Laser Scanning Detection

In recent years, exosomes have attracted attention in many aspects from basic research to clinical application, including therapeutic reagents or biomarkers for liquid biopsy. The increasing understanding of exosome's heterogeneous properties is expected to lead to more advanced exosome research, and there is therefore a need for a multiplex system that can easily classify and analyze exosomes in complex biological samples according to their properties. In this study, we developed a simple and sensitive multiplexed exosome quantification system based on ExoCounter, an exosome quantification system utilizing optical disk technology, by introducing nanobeads made of different materials as exosome labeling substances. The refractive indices suitable for nanobead materials were analyzed by computer simulation of optical diffraction generated by nanobeads. The results showed that polymer (FG), Au, and Ag nanobeads exhibited superior discrimination capability in terms of the amplitude and polarity of detection pulses generated by each nanobead. The specificity and detection sensitivity of three types of nanobeads were confirmed by detecting HER2-positive exosomes with anti-HER2 antibody-conjugated nanobeads. Furthermore, CD147-positive, HER2-positive, and CD81-positive exosomes in 12.5 μL of serum were simultaneously quantified with high discrimination performance using the anti-CD147 antibody, anti-HER2 antibody, or anti-CD81 antibody conjugated for FG beads, Au nanobeads, or Ag nanobeads, respectively. A limit of detection was also evaluated as low as 210 exosomes/μL. This system is a promising tool for advanced exosome research because it enables multiplexed detection of heterogeneous exosomes in serum with high specificity, accuracy, and sensitivity without purification.

Revolutionizing Nanotechnology with Filago desertorum Extracts: Biogenic Synthesis of Silver Nanoparticles Exhibiting Potent Antioxidant and Antibacterial Activities

In this study, we described the environmentally friendly biosynthesis of silver nanoparticles (AgNPs) utilizing ethanolic extract of Filago desertorum (F. desertorum) as a capping and reducing agent. We also looked at the antioxidant and antibacterial capacities of AgNPs. In order to determine the size, shape, and crystallinity of the created AgNPs, the current project was designed to produce AgNPs utilizing the crude extract of the F. desertorum. The effectiveness of the project was evaluated by UV-visible spectrophotometry, Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. AgNPs are monodispersed and spherical and have 50 nm average particle diameters, as determined using Image J software calculations and SEM observation. Four significant peaks from an XRD study, located at 38.46, 44.63, 64.81, and 77.74 nm, were used to calculate the average crystalline size of AgNPs which was reported to be 15 nm. In the crude extract of F. desertorum, it is possible to see the functional group peaks of a number of substances that are essential for bioreduction and the stability of the AgNPs. Antibacterial and antioxidant properties of AgNPs in vitro (DPPH, ABTS, H2O2, phosphomolybdenum, and ferric reducing power) were examined using conventional methods. The AgNPs showed maximum DPPH (72.51% with IC50 = 144.61 μg/mL), ABTS (75.24% with IC50 = 131.21 μg/mL), hydrogen peroxide (73.33% with IC50 = 115.05 μg/mL), phosphomolybdenum activity (73.43% with IC50 = 75.25 μg/mL), and observing reducing power (0.25) at a concentration of 250 g/mL. Inhibition by the AgNPs against the bacterial strain Staphylococcus aureus was greatest (12 mm). According to the current findings, AgNPs produced by F. desertorum have the highest potential for free radical scavenging and antibacterial activity, which can result in antioxidant and antibiotic agents.

Enhancing the Ag-loading capacity on Ti3C2Tx sheets as hybrid fillers to form composite coatings with excellent antibacterial properties

The settlement of microorganisms is an unwanted process in various practical fields, where also the first attaching microorganisms could promote other bacterial adhesion, causing an acceleration of bioaccumulation on the solid surface and damage to the surface functions. Developing an advanced composite coating with anti-microorganism attachment features is still a big challenge, and the critical element in any such method is to find an efficient functional agent for use in the coating system that could extend the service period. MXenes have received increasing attentions owing to their unique layer structure and large specific surface area. Increasing studies have been devoted to the development of MXene/polymer composites with creatively designed structures to realize various specific functions. Herein, two-dimensional (2D) transition metal carbide material MXene as a carrier was etched and decorated with cellulose to enhance the anchor points to grasp functional Ag nanoparticles via a simple method. The MXene nanosheets (Ti3C2Tx) were modified by cellulose to graft hydroxy groups on their surface, and then they were incorporated into silver nanoparticles (Ag NPs). The results showed that the cellulose could increase the loading content of the Ag NPs on the MXene surface, and also could act as a stabilized material to form the composite filler MXene@cellulose@Ag NPs (MAC), which could serve as a functional agent. Furthermore, the obtained product MAC filler exhibited excellent dispersibility and stability among all the tested fillers (MXene and MA), and it could help avoid aggregation and promote homogenous dispersal in the coating network. Besides, MAC displayed outstanding antibacterial activities against E. coli and S. aureus at the same concentration among all the fillers. When the filler was embedded into the coating system, the composite coating PCB-MAC possessed abundant active Ag+ ions released by the Ag NPs, which could work against bacterial growth and achieve a favorable antibacterial inhibition effect. Therefore, we believe that the active MAC filler maintained high antibacterial efficiency, evincing its potential as a desirable agent for obtaining an excellent anti-adhesive behavior in numerous broad applications, such as the environment field or medical area.

Advances in therapeutic applications of silver nanoparticles

Nanotechnology is one of the most appealing area for developing new applications in biotechnology and medicine. For decades, nanoparticles have been extensively studied for a variety of biomedical applications. Silver has evolved into a potent antibacterial agent that can be used in a variety of nanostructured materials of various shapes and sizes. Silver nanoparticles (AgNP) based antimicrobial compounds are employed in a wide range of applications, including medicinal uses, surface treatment and coatings, the chemical and food industries, and agricultural productivity. When designing formulations for specific applications, the size, shape, and surface area of AgNPs are all crucial structural aspects to consider. Different methods for producing AgNPs with varying sizes and forms that are less harmful have been devised. The anticancer, anti-inflammatory, antibacterial, antiviral, and anti-angiogenic properties of AgNPs have been addressed in this review, as well as their generation and processes. Herein, we have reviewed the advances in therapeutic applications of AgNPs, as well as their limitations and barriers for future applications.

Recent advances in cellulose nanocrystals-based antimicrobial agents

Over the past five years, there has been growing interest in the design of modified cellulose nanocrystals (CNCs) as nanoscale antimicrobial agents in potential end-user applications such as food preservation/packaging, additive manufacturing, biomedical and water purification. The interest of applying CNCs-based antimicrobial agents arise due to their abilities to be derived from renewable bioresources and their excellent physicochemical properties including rod-like morphologies, large specific surface area, low toxicity, biocompatibility, biodegradability and sustainability. The presence of ample surface hydroxyl groups further allows easy chemical surface modifications for the design of advanced functional CNCs-based antimicrobial materials. Furthermore, CNCs are used to support antimicrobial agents that are subjected to instability issues. The current review summarizes recent progress in CNC-inorganic hybrid-based materials (Ag and Zn nanoparticles, other metal/metal oxide) and CNC-organic hybrid-based materials (polymers, chitosan, simple organic molecules). It focuses on their design, syntheses and applications with a brief discussion on their probable modes of antimicrobial action whereby the roles of CNCs and/or the antimicrobial agents are highlighted.

Boosting Antibacterial Photodynamic Therapy in a Nanosized Zr MOF by the Combination of Ag NP Encapsulation and Porphyrin Doping

Antibacterial photodynamic therapy (aPDT) is regarded as one of the most promising antibacterial therapies due to its nonresistance, noninvasion, and rapid sterilization. However, the development of antibacterial materials with high aPDT efficacy is still a long-standing challenge. Herein, we develop an effective antibacterial photodynamic composite UiO-66-(SH)2@TCPP@AgNPs by Ag encapsulation and 4,4',4″,4‴-(porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid) (TCPP) dopant. Through a mix-and-match strategy in the self-assembly process, 2,5-dimercaptoterephthalic acid containing -SH groups and TCPP were uniformly decorated into the UiO-66-type framework to form UiO-66-(SH)2@TCPP. After Ag(I) impregnation and in situ UV light reduction, Ag NPs were formed and encapsulated into UiO-66-(SH)2@TCPP to get UiO-66-(SH)2@TCPP@AgNPs. In the resulting composite, both Ag NPs and TCPP can effectively enhance the visible light absorption, largely boosting the generation efficiency of reactive oxygen species. Notably, the nanoscale size enables it to effectively contact and be endocytosed into bacteria. Consequently, UiO-66-(SH)2@TCPP@AgNPs show a very high aPDT efficacy against Gram-negative and Gram-positive bacteria as well as drug-resistant bacteria (MRSA). Furthermore, the Ag NPs were firmly anchored at the framework by the high density of -SH moieties, avoiding the cytotoxicity caused by the leakage of Ag NPs. By in vitro experiments, UiO-66-(SH)2@TCPP@AgNPs show a very high antibacterial activity and good biocompatibility as well as the potentiality to promote cell proliferation.

Antibiotic-Loaded Boron Nitride Nanoconjugate with Strong Performance against Planktonic Bacteria and Biofilms

Protecting surfaces from biofilm formation presents a significant challenge in the biomedical field. The utilization of antimicrobial component-conjugated nanoparticles is becoming an attractive strategy against infectious biofilms. Boron nitride (BN) nanomaterials have a unique biomedical application value due to their excellent biocompatibility. Here, we developed antibiotic-loaded BN nanoconjugates to combat bacterial biofilms. Antibiofilm testing included two types of pathogens, Staphylococcus aureus and Escherichia coli. Gentamicin was loaded on polydopamine-modified BN nanoparticles (GPBN) to construct a nanoconjugate, which was very effective in killing E. coli and S. aureus planktonic cells. GPBN exhibited equally strong capacity for biofilm destruction, tested on preformed biofilms. A 24 h treatment with the nanoconjugate reduced cell viability by more than 90%. Our results suggest that GPBN adheres to the surface of the biofilm, penetrates inside the biofilm matrix, and finally deactivates the cells. Interestingly, the GPBN coatings also strongly inhibited the formation of bacterial biofilms. Based on these results, we suggest that GPBN could serve as an effective means for treating biofilm-associated infections and as coatings for biofilm prevention.

G. M, Pandit S, Alghamdi S, Almehmadi M, Allahyani M, Awwad NS, Sharma R. Eco-friendly synthesized nanoparticles as antimicrobial agents: an updated review

Green synthesis of NPs has gained extensive acceptance as they are reliable, eco-friendly, sustainable, and stable. Chemically synthesized NPs cause lung inflammation, heart problems, liver dysfunction, immune suppression, organ accumulation, and altered metabolism, leading to organ-specific toxicity. NPs synthesized from plants and microbes are biologically safe and cost-effective. These microbes and plant sources can consume and accumulate inorganic metal ions from their adjacent niches, thus synthesizing extracellular and intracellular NPs. These inherent characteristics of biological cells to process and modify inorganic metal ions into NPs have helped explore an area of biochemical analysis. Biological entities or their extracts used in NPs include algae, bacteria, fungi, actinomycetes, viruses, yeasts, and plants, with varying capabilities through the bioreduction of metallic NPs. These biosynthesized NPs have a wide range of pharmaceutical applications, such as tissue engineering, detection of pathogens or proteins, antimicrobial agents, anticancer mediators, vehicles for drug delivery, formulations for functional foods, and identification of pathogens, which can contribute to translational research in medical applications. NPs have various applications in the food and drug packaging industry, agriculture, and environmental remediation.

Multifactorial role of nanoparticles in alleviating environmental stresses for sustainable crop production and protection

In the era of dire environmental fluctuations, plants undergo several stressors during their life span, which severely impact their development and overall growth in negative aspects. Abiotic stress factors, especially moisture stress i.e shortage (drought) or excess (flooding), salinity, temperature divergence (i.e. heat and cold stress), heavy metal toxicity, etc. create osmotic and ionic imbalance inside the plant cells, which ultimately lead to devastating crop yield, sometimes crop failure. Apart from the array of abiotic stresses, various biotic stress caused by pathogens, insects, and nematodes also affect production. Therefore, to combat these major challenges in order to increase production, several novel strategies have been adapted, among which the use of nanoparticles (NPs) i.e. nanotechnology is becoming an emerging tool in various facets of the current agriculture system, nowadays. This present review will elaborately depict the deployment and mechanisms of different NPs to withstand these biotic and abiotic stresses, along with a brief overview and indication of the future research works to be oriented based on the steps provided for future research in advance NPs application through the sustainable way.

Biocompatibility and inflammatory response of silver tungstate, silver molybdate, and silver vanadate microcrystals

Silver tungstate (α-Ag2WO4), silver molybdate (β-Ag2MoO4), and silver vanadate (α-AgVO3) microcrystals have shown interesting antimicrobial properties. However, their biocompatibility is not yet fully understood. Cytotoxicity and the inflammatory response of silver-containing microcrystals were analyzed in THP-1 and THP-1 differentiated as macrophage-like cells, with the alamarBlue™ assay, flow cytometry, confocal microscopy, and ELISA. The present investigation also evaluated redox signaling and the production of cytokines (TNFα, IL-1β, IL-6, and IL-8) and matrix metalloproteinases (MMP-8 and -9). The results showed that α-AgVO3 (3.9 μg/mL) did not affect cell viability (p > 0.05). α-Ag2WO4 (7.81 μg/mL), β-Ag2MoO4 (15.62 μg/mL), and α-AgVO3 (15.62 μg/mL) slightly decreased cell viability (p ≤ 0.003). All silver-containing microcrystals induced the production of O2 - and this effect was mitigated by Reactive Oxygen Species (ROS) scavenger and N-acetylcysteine (NAC). TNFα, IL-6 and IL-1β were not detected in THP-1 cells, while their production was either lower (p ≤ 0.0321) or similar to the control group (p ≥ 0.1048) for macrophage-like cells. The production of IL-8 by both cellular phenotypes was similar to the control group (p ≥ 0.3570). The release of MMP-8 was not detected in any condition in THP-1 cells. Although MMP-9 was released by THP-1 cells exposed to α-AgVO3 (3.9 μg/mL), no significant difference was found with control (p = 0.7). Regarding macrophage-like cells, the release of MMP-8 and -9 decreased in the presence of all microcrystals (p ≤ 0.010). Overall, the present work shows a promising biocompatibility profile of, α-Ag2WO4, β-Ag2MoO4, and α-AgVO3 microcrystals.

The Occurrence of Oxidative Stress Induced by Silver Nanoparticles in Chlorella vulgaris Depends on the Surface-Stabilizing Agent

Silver nanoparticles (AgNPs) are of great interest due to their antimicrobial properties, but their reactivity and toxicity pose a significant risk to aquatic ecosystems. In biological systems, AgNPs tend to aggregate and dissolve, so they are often stabilized by agents that affect their physicochemical properties. In this study, microalga Chlorella vulgaris was used as a model organism to evaluate the effects of AgNPs in aquatic habitats. Algae were exposed to AgNPs stabilized with citrate and cetyltrimethylammonium bromide (CTAB) agents and to AgNO₃ at concentrations that allowed 75% cell survival after 72 h. To investigate algal response, silver accumulation, ROS content, damage to biomolecules (lipids, proteins, and DNA), activity of antioxidant enzymes (APX, PPX, CAT, SOD), content of non-enzymatic antioxidants (proline and GSH), and changes in ultrastructure were analyzed. The results showed that all treatments induced oxidative stress and adversely affected algal cells. AgNO₃ resulted in the fastest death of algae compared to both AgNPs, but the extent of oxidative damage and antioxidant enzymatic defense was similar to AgNP-citrate. Furthermore, AgNP-CTAB showed the least toxic effect and caused the least oxidative damage. These results highlight the importance of surface-stabilizing agents in determining the phytotoxicity of AgNPs and the underlying mechanisms affecting aquatic organisms.

Alleviation of chromium stress in plants using metal and metal oxide nanoparticles

Chromium (Cr), one of the hazardous pollutants, exists predominantly as Cr(VI) and Cr(III) in the environment. Cr(VI) is more toxic than Cr(III) due to its high mobility and solubility. Elevated levels of Cr in agricultural soil due to various anthropogenic activities cause Cr accumulation in plants, resulting in a significant reduction in plant yield and quality due to Cr-induced physiological, biochemical and molecular alterations. It can infiltrate the food chain through crop plants and cause harmful effects in humans via biomagnification. Cr(VI) is linked to cancer in humans. Therefore, mitigation strategies are required to remediate Cr-polluted soils and limit its accumulation in plants for safe food production. Recent research on metal and metal oxide nanoparticles (NPs) has shown that they can effectively reduce Cr accumulation and phytotoxicity. The effects of these NPs are influenced by their type and dose, exposure method, plant species and experimental settings. In this review, we present an up-to-date compilation and comprehensive analysis of the existing literature regarding the process of uptake and distribution of Cr and impact and potential mechanisms of metal and metal oxide nanoparticles led mitigation of Cr-induced stress in plants. We have also discussed recent developments, existing research gaps and future research directions in the field of Cr stress mitigation by NPs in plants. Overall, this review can provide valuable insights in reducing Cr accumulation and toxicity using metal and metal oxide nanoparticles, thereby promoting safe and sustainable cultivation of food and phytostabilization of Cr-polluted soil.

Complexation of turmeric and curcumin mediated silver nanoparticles with human serum albumin: Further investigation into the protein-corona formation, anti-bacterial effects and cell cytotoxicity studies

Biosynthesized noble metal nanoparticles have been of recent interest due to their broad implications in the future biomedicinal field. We have synthesized silver nanoparticle using turmeric-extract and its major component curcumin as reducing and stabilizing agents. Further, we have investigated the protein-NPs interaction focusing the inspection of the role of biosynthesized AgNPs on any conformational changes of the protein, binding and thermodynamic parameters using spectroscopic techniques. Fluorescence quenching studies revealed that both CUR-AgNPs and TUR-AgNPs have moderate binding affinities (∼10⁴ M^-1) towards human serum albumin (HSA) and static quenching mechanism was involved in the binding. Estimated thermodynamic parameters indicate the involvement of hydrophobic forces in the binding processes. The surface charge potential of the biosynthesized AgNPs became more negative upon complexation with HSA as observed from Zeta potential measurements. Antibacterial efficacies of the biosynthesized AgNPs were evaluated against Escherichia coli (gram-negative) and Enterococcus faecalis (gram-positive) bacterial strains. The AgNPs were found to destroy the cancer (HeLa) cell lines in vitro. The overall findings of our study successfully outline the detailed insight of the protein corona formation by biocompatible AgNPs and their biological applications concerning the future scope in the biomedicinal field.

Silver Nanoparticles Enhance Oxidative Stress, Inflammation, and Apoptosis in Liver and Kidney Tissues: Potential Protective Role of Thymoquinone

Silver nanoparticles (AgNPs) are the most common nanomaterials in consumer products. Therefore, it has been crucial to control AgNPs toxicological effects to improve their safety and increase the outcome of their applications. This work investigated the possible protective effect of thymoquinone (TQ) against AgNPs-induced hepatic and renal cytotoxicity in rats. Serum markers of liver and kidney functions as well as liver and kidney oxidative stress status, pro-inflammatory cytokines, apoptosis markers, and histopathology were assessed. TQ reversed AgNPs-induced elevation in serum liver and kidney function markers, including aspartate transaminase, alanine transaminase, urea, and creatinine. Moreover, TQ co-administration with AgNPs alleviates hepatic and renal oxidative insults by decreasing MDA and NO levels with a significant increase in the activity of antioxidant enzymes (superoxide dismutase, catalase, and glutathione recycling enzymes peroxidase and reductase) compared to AgNPs-treated rats. Besides, TQ upregulated hepatic and renal Nrf2 gene expression in AgNPs-intoxicated rats. Furthermore, TQ co-administration decreased the hepatic and renal pro-inflammatory mediators represented by IL-1β, TNF-α, TGF-β, and NF-κB levels. Besides, TQ co-administration decreased apoptotic protein (Bax) levels and increased the anti-apoptotic protein (Bcl-2) levels. These findings were confirmed by the histopathological examination of hepatic and renal tissues. Our data affirmed the protective effect of TQ against AgNPs cytotoxicity and proposed a possible mechanism of TQ antioxidant, anti-inflammatory, and anti-apoptotic effects. Consequently, we could conclude that using TQ might control AgNPs toxicological effects, improve their safety, and increase the outcome of their applications.

Evolution of nanostructured skin patches towards multifunctional wearable platforms for biomedical applications

Recent advances in the field of skin patches have promoted the development of wearable and implantable bioelectronics for long-term, continuous healthcare management and targeted therapy. However, the design of electronic skin (e-skin) patches with stretchable components is still challenging and requires an in-depth understanding of the skin-attachable substrate layer, functional biomaterials and advanced self-powered electronics. In this comprehensive review, we present the evolution of skin patches from functional nanostructured materials to multi-functional and stimuli-responsive patches towards flexible substrates and emerging biomaterials for e-skin patches, including the material selection, structure design and promising applications. Stretchable sensors and self-powered e-skin patches are also discussed, ranging from electrical stimulation for clinical procedures to continuous health monitoring and integrated systems for comprehensive healthcare management. Moreover, an integrated energy harvester with bioelectronics enables the fabrication of self-powered electronic skin patches, which can effectively solve the energy supply and overcome the drawbacks induced by bulky battery-driven devices. However, to realize the full potential offered by these advancements, several challenges must be addressed for next-generation e-skin patches. Finally, future opportunities and positive outlooks are presented on the future directions of bioelectronics. It is believed that innovative material design, structure engineering, and in-depth study of fundamental principles can foster the rapid evolution of electronic skin patches, and eventually enable self-powered close-looped bioelectronic systems to benefit mankind.

Enhancement of Fluorescence Mediated by Silver Nanoparticles: Implications for Cell Imaging

In this study, we report the surface enhanced fluorescence (SEF) of a biologically important organic dye, fluorescein (FL), by silver nanoparticles (Ag NPs) in an aqueous medium and its implications for human cell imaging. The as-synthesized Ag NPs were characterized by dynamic light scattering (DLS), zeta potential, transmission electron microscopy (TEM), and UV-vis absorption spectroscopic studies. The interaction and aggregation of FL dye with Ag NPs and a cationic surfactant, namely, cetyltrimethylammonium bromide (CTAB), were explored by UV-vis absorption and steady-state and time-resolved fluorescence spectroscopic methods. The distance-dependent fluorescence enhancement of FL due to Ag NPs in the solution was also theoretically correlated by three-dimensional finite-difference time-domain (3D-FDTD) simulation. The plasmonic coupling between neighboring NPs facilitated the augmentation of the local electric field, thereby producing various "hotspots" that influence the overall fluorescence of the emitter. J-type aggregates of FL in the presence of the CTAB micelles and Ag NP mixed solution were confirmed by electronic spectroscopy. The density functional theoretical (DFT) study revealed the electronic energy levels associated with different forms of FL dye in the aqueous solution. Most interestingly, the Ag NP/FL mixed system used in fluorescence imaging of human lung fibroblast cells (WI 38 cell line) showed a significantly stronger green fluorescence signal compared to that of FL after an incubation period of only 3 h. This study confirms that the Ag NP mediated SEF phenomenon of the FL dye is also manifested in the intracellular medium of human cells giving a brighter and more intense fluorescence image. The cell viability test after exposure to the Ag NP/FL mixed system was confirmed by the MTT assay method. The proposed study may have an implication as an alternate approach for human cell imaging with higher resolution and more contrast.

Silver nanoparticles combat Salmonella Typhimurium: Suppressing intracellular infection and activating dendritic cells

Salmonella Typhimurium (ST) can hide inside cells, avoid antibiotic therapy and being killed by host's immune system to cause persistent infection in humans and animals. Metal nanoparticles are regarded as an alternative to overcome the above limitations, silver nanoparticles especially have been applied in combating drug-resistant bacteria. However, the therapeutic effects of silver nanoparticles against intracellular infection and their impacts on host immunity remain an area of further investigation. In this work, we synthesized Ganoderma extract-capped silver nanoparticles (Ag@Ge) and explored the therapeutic potential and immune adjuvant effects of Ag@Ge against intracellular ST. Firstly, Ag@Ge had a small particle size of 35.52±7.46 nm, good stability, and biocompatibility. Then, Ag@Ge effectively entered RAW 264.7 cells, suppressed intracellular ST infection. Furthermore, Ag@Ge activated mouse dendritic cells (DCs) in vitro, evidenced by increased phenotypic markers (CD80/CD86/CD40/major compatibility complex II (MHCII)) expression and cytokine and chemokine (interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), chemokine (C-C motif) ligand 2 (CCL-2), and chemokine (C-C motif) receptor-7 (CCR-7)) transcription. More notably, the combination of Ag@Ge with inactivated ST recruited intestinal DCs to mitigate ST infection in mice, evidenced by decreased body weight loss and bacterial loads in the tissues (liver, jejunum, and colon), and improved platelets count. The above findings indicate that Ag@Ge has the potential as an alternative nano-antibiotic against intracellular ST infection.

The Biochemical Effects of Silver Nanoparticles and Spirulina Extract on Experimentally Induced Prostatic Cancer in Rats

Prostate cancer (PCa) is the most diagnosed cancer in 112 countries and the second leading cause of death in men in 48 countries. We studied the outstanding agents silver nanoparticles (AgNPs) and Spirulina algae (Sp) for the management of PCa once as monotherapy or last as a combination. PCa in rats was induced using bicalutamide (Casodex®) and testosterone, followed by (7, 12-dimethylbenz[a]anthracene). Then, testosterone was injected s.c. for 3 months. Rats were divided into six groups, with 12 rats in each group. Group I was assigned as the control (co), group II as the PCa model, group III treated with AgNPs, group IV treated with Spirulina extract, group V treated with a combination of AgNPs plus Spirulina, and group VI treated with bicalutamide. The results show that AgNPs could normalize IL-6 levels and could overcome the hormonal disturbance induced in PCa rats along the hypothalamic-pituitary-testis axis. Spirulina revealed a significant reduction in the level of total and free prostatic specific antigen (PSA) to the same level as bicalutamide treatment, which was the same as the control group. Histopathological study revealed regression (75%) of the histological pattern of high-grade prostatic intraepithelial neoplasia (HGPIN) for Spirulina alone, and (50%) for bicalutamide. The best effect on IL-6 decline was reached with the AgNPs/Spirulina combination as well as bicalutamide treatment compared with the PCa group. Bicalutamide treatment significantly decreased the PSA concentration relative to the PCa group and reached the normal level. Adding Spirulina to AgNPs as a combination enhanced its effect on all mentioned drawbacks associated with PCa except hormonal imbalance that needs more adjustments.

Optical, structural and antibacterial properties of silver nanoparticles and DNA-templated silver nanoclusters

Silver nanoparticles (AgNPs) are increasingly considered for biomedical applications as drug-delivery carriers, imaging probes and antibacterial agents. Silver nanoclusters (AgNCs) represent another subclass of nanoscale silver. AgNCs are a promising tool for nanomedicine due to their small size, structural homogeneity, antibacterial activity and fluorescence, which arises from their molecule-like electron configurations. The template-assisted synthesis of AgNCs relies on organic molecules that act as polydentate ligands. In particular, single-stranded nucleic acids reproducibly scaffold AgNCs to provide fluorescent, biocompatible materials that are incorporable in other formulations. This mini review outlines the design and characterization of AgNPs and DNA-templated AgNCs, discusses factors that affect their physicochemical and biological properties, and highlights applications of these materials as antibacterial agents and biosensors.

Effects of Au States in Thiol-Organosilica Nanoparticles on Enzyme-like Activity for X-ray Sensitizer Application: Focus on Reactive Oxygen Species Generation in Radiotherapy

In radiotherapy, the use of Au nanoparticles (Au NPs) has been proposed to enhance cell damage by X-ray irradiation. Although the role of Au in radiotherapy is not fully understood, the catalytic activity of Au has been actively studied in the industrial field. Moreover, owing to their enzyme-like activity and high biocompatibility in vitro and in vivo, Au NPs present significant potential for biological applications. In this study, we incorporated different Au states both on the surface and embedded in thiol-organosilica (thiol-OS/Au series) to investigate the efficiency of anticancer cell activity of Au in radiotherapy. The thiol-OS/Au series comprised different Au(I)/Au(0) ratios and Au NPs, and different sizes of Au NPs were embedded in thiol-OS/Au. These thiol-OS/Au series samples were evaluated for enzyme-like activities in reactive oxygen species (ROS) generation by X-ray irradiation. Thiol-OS/Au embedded with small Au NPs (AC600/thiol-OS/Au) exhibited peroxidase (POD)-like activity under acidic conditions. This POD-like activity improved ROS generation and cytotoxicity under X-ray irradiation. Furthermore, AC600/thiol-OS/Au exhibited catalase (CAT)-like activity under basic conditions and showed no cytotoxicity toward nonirradiated cells. These results revealed the efficiency of functionalizing with small Au NPs that possess pH-controlled POD- and CAT-like activity as a radiosensitizer. We compared the suitability of using Au with different states to obtain the thiol-OS/Au series samples for application as radiosensitizers. The findings of this study will aid the design of efficacious strategies for the Au nanostructure-based radiotherapy of cancer cells.

Metal-Based Nanoparticles and Their Relevant Consequences on Cytotoxicity Cascade and Induced Oxidative Stress

Emerging nanoscience allows us to take advantage of the improved evolutionary components and apply today’s advanced characterization and fabrication techniques to solve environmental and biological problems. Despite the promise that nanotechnology will improve our lives, the potential risks of technology remain largely uncertain. The lack of information on bio-impacts and the absence of consistent standards are the limitations of using metal-based nanoparticles (mNPs) for existing applications. To analyze the role played by the mNPs physicochemical characteristics and tactics to protect live beings, the field of nanotoxicology nowadays is focused on collecting and analyzing data from in vitro and in vivo investigations. The degree of reactive oxygen species (ROS) and oxidative stress caused by material nanoparticles (NPs) depends on many factors, such as size, shape, chemical composition, etc. These characteristics enable NPs to enter cells and interact with biological macromolecules and cell organelles, resulting in oxidative damage, an inflammatory response, the development of mitochondrial dysfunction, damage to genetic material, or cytotoxic effects. This report explored the mechanisms and cellular signaling cascades of mNPs-induced oxidative stress and the relevant health consequences.

Toxicological Aspects, Safety Assessment, and Green Toxicology of Silver Nanoparticles (AgNPs)—Critical Review: State of the Art

In recent years, research on silver nanoparticles (AgNPs) has attracted considerable interest among scientists because of, among other things, their alternative application to well-known medical agents with antibacterial properties. The size of the silver nanoparticles ranges from 1 to 100 nm. In this paper, we review the progress of research on AgNPs with respect to the synthesis, applications, and toxicological safety of AgNPs, and the issue of in vivo and in vitro research on silver nanoparticles. AgNPs’ synthesis methods include physical, chemical, and biological routes, as well as “green synthesis”. The content of this article covers issues related to the disadvantages of physical and chemical methods, which are expensive and can also have toxicity. This review pays special attention to AgNP biosafety concerns, such as potential toxicity to cells, tissues, and organs.

Antimicrobial Nanomaterials as Advanced Coatings for Self-Sanitizing of Textile Clothing and Personal Protective Equipment

Controlling bioaerosols has become increasingly critical in affecting human health. Natural product treatment in the nano form is a potential method since it has lower toxicity than inorganic nanomaterials like silver nanoparticles. This research is important for the creation of a bioaerosol control system that is effective. Nanoparticles (NPs) are gradually being employed to use bacteria as a nonantibiotic substitute for treating bacterial infections. The present study looks at nanoparticles' antimicrobial properties, their method of action, their impact on drug-opposing bacteria, and the hazards connected with their operation as antimicrobial agents. The aspects that influence nanoparticle conduct in clinical settings, as well as their distinctive features and mode of action as antibacterial assistants, are thoroughly examined. Nanoparticles' action on bacterial cells is presently accepted by way of the introduction of oxidative stress induction, metal-ion release, and nonoxidative methods. Because many concurrent mechanisms of action against germs would necessitate multiple simultaneous gene modifications in the same bacterial cell for antibacterial protection to evolve, bacterial cells developing resistance to NPs is difficult. This review discusses the antimicrobial function of NPs against microbes and presents a comprehensive discussion of the bioaerosols: their origin, hazards, and their prevention. This state of the art method is dependent upon the use of personal protective gear against these bioaerosols. The benefit of the utmost significant categories of metal nanoparticles as antibacterial agents is given important consideration. The novelty of this review depends upon the antimicrobial properties of (a) silver (Ag), (b) zinc oxide (ZnO), and (c) copper oxide (CuO) nanoparticles. The value-added features of these nanoparticles are discussed, as well as their physicochemical characterization and pharmacokinetics, including the toxicological danger they pose to people. Lastly, the effective role of nanomaterials and their future in human wellness is discussed.

Comparative proteomic analysis reveals the different hepatotoxic mechanisms of human hepatocytes exposed to silver nanoparticles

Silver nanoparticles (AgNPs), which have been used extensively in consuming products and eventually released into the natural environment, have aroused concerns recently because of their potentially harmful effects on human beings following various routes of exposure. As the liver is one of the largest accumulation and deposition sites of circulatory AgNPs, it is important to evaluate the hepatotoxicity induced by AgNPs. However, the acting mechanisms of AgNPs-induced hepatotoxicity are still elusive to a great extent. Herein, we investigated the hepatotoxic effects of AgNPs using a comparative proteomics approach. First, we evaluated the cytotoxicity of different-sized AgNPs and found that the cancerous liver cells were generally more sensitive than the normal liver cells. Next, proteomics results suggested that HepG2 and L02 cells showed distinct adaptive responses upon AgNPs exposure. HepG2 cells respond to stresses by adapting energy metabolism, upregulating metallothionein expression and increasing the expression of antioxidants, while L02 cells protect themselves by increasing DNA repair and macro-autophagy. Besides, mitochondrial ROS has been identified as one of the causes of AgNPs-induced hepatotoxicity. Collectively, our results revealed that hepatic cancer cells and normal cells cope with AgNPs in notably different pathways, providing new insights into mechanisms underlying AgNPs-induced hepatotoxicity. DATA AVAILABILITY: The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium (Deutsch et al. (2020)) via the PRIDE (Perez-Riverol et al. (2019)) partner repository with the dataset identifier PXD029511.

Assessing the effects of silver nanoparticles on the ecophysiology of Gammarus roeseli

Being part of the macrobenthic fauna, gammarids are efficient indicators of contamination of aquatic ecosystems by nanoparticles that are likely to sediment on the bottom. The present study investigates the effects of silver nanoparticles (nAg) on ecophysiological functions in Gammarus roeseli by using a realistic scenario of contamination. Indeed, an experiment was conducted during 72 h, assessing the effects of 5 silver nAg from 10 to 100 nm diluted at concentrations of maximum 5 µg L^-1 in a natural water retrieved from a stream and supplemented with food. The measured endpoints in gammarids were survival, silver concentrations in tissues, consumption of oxygen and ventilation of gills. Additionally, a set of biomarkers of the energetic metabolism was measured. After a 72-h exposure, results showed a concentration-dependent increase of silver levels in G. roeseli that was significant for the smallest nAg size (10 nm). Ecophysiological responses in G. roeseli were affected and the most striking effect was a concentration-dependent increase in oxygen consumption especially for the smallest nAg (10 to 40 nm), whereas ventilation of gills by gammarids was not changed. The potential mechanisms underlying these findings are discussed. Thus, we demonstrated the very low exposure concentration of 0.5 µg L^-1 for the small nAg size led to significant ecophysiological effects reinforcing the need to further investigate subtle effects on nanoparticles on aquatic organisms.

Silver nanoparticles inhibit nitrogen fixation in soybean (Glycine max) root nodules

Antimicrobial silver nanoparticles (AgNPs) are popular in consumer and industrial products, leading to increasing concentrations in the environment. We tested whether exposure to AgNPs could be detrimental to a microbe, its host plant, and their symbiotic relationship. When subjected to 10 µg/mL AgNPs, growth of Bradyrhizobium japonicum USDA 110 was halted. Axenic nitrogen-fertilized Glycine max seedlings were unaffected by 2.5 µg/mL of 30 nm AgNPs, but growth was inhibited with the same dose of 16 nm AgNPs. With 2.5 µg/mL AgNPs, biomass of inoculated plants was 50% of the control. Bacteroids were not found in nodules on plants treated with 2.5 µg/mL AgNPs and plants given 0.5-2.5 µg/mL AgNPs had 40-65% decreased nitrogen fixation. In conclusion, AgNPs not only interfere with general plant and bacterial growth but also inhibit nodule development and bacterial nitrogen fixation. We should be mindful of not releasing AgNPs to the environment or to agricultural land.

Physicochemical Transformations of Silver Nanoparticles in the Oro-Gastrointestinal Tract Mildly Affect Their Toxicity to Intestinal Cells In Vitro: An AOP-Oriented Testing Approach

The widespread use of silver nanoparticles (Ag NPs) in food and consumer products suggests the relevance of human oral exposure to these nanomaterials (NMs) and raises the possibility of adverse effects in the gastrointestinal tract. The aim of this study was to investigate the toxicity of Ag NPs in a human intestinal cell line, either uncoated or coated with polyvinylpyrrolidone (Ag PVP) or hydroxyethylcellulose (Ag HEC) and digested in simulated gastrointestinal fluids. Physicochemical transformations of Ag NPs during the different stages of in vitro digestion were identified prior to toxicity assessment. The strategy for evaluating toxicity was constructed on the basis of adverse outcome pathways (AOPs) showing Ag NPs as stressors. It consisted of assessing Ag NP cytotoxicity, oxidative stress, genotoxicity, perturbation of the cell cycle and apoptosis. Ag NPs caused a concentration-dependent loss of cell viability and increased the intracellular level of reactive oxygen species as well as DNA damage and perturbation of the cell cycle. In vitro digestion of Ag NPs did not significantly modulate their toxicological impact, except for their genotoxicity. Taken together, these results indicate the potential toxicity of ingested Ag NPs, which varied depending on their coating but did not differ from that of non-digested NPs.