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

Camellia sinensis mediated silver nanoparticles: eco-friendly antimicrobial agent to control multidrug resistant Gram-positive Staphylococcus aureus

Staphylococcus aureus provokes several clinical infections, and its treatment remains challenging due to the rise of multidrug-resistant strains. In the current scenario it's a vital need for alternative strategies to control the spread of MDR S. aureus. Therefore, considerable effort has been put forth to develop green nanoparticles. Camellia sinensis is enriched with phytocompounds with potent antibacterial properties. Green synthesis strategy is more sustainable and non-toxic compared to traditional chemical processes. CsAgNps was synthesized by mixing 1 part of fresh extract of C. sinensis extract with 2 parts of 1mM silver and employing photocatalytic reduction for the period of 8 h until visible colour change was observed. Synthesized CsAgNps were characterized by employing various techniques to study the size, charge, topography and elemental composition. According to the findings of the in-silico analysis, phytocompounds of C. sinensis including Protopine, Ellagic acid, Catechin and Techtochrysin were recognized as potential lead compounds against various virulent targets in S. aureus. CsAgNps were tested for its antimicrobial and antibiofilm activity in MDR and MTCC (1430). The study results showed that it controls growth and biofilm formation of strains at the concentration of 12.5 µg/mL. The potential lead compounds against various virulent targets in S. aureus were analyzed using in-silico technique. Future research in the development of healthcare products will focus on optimization of ecofriendly material with targeted and sustainable release and enhancing antimicrobial efficacy particularly on MDR pathogens. CsAgNps can be incorporated to develop nano-based health care products to control antibiotic resistant S. aureus infections.

Antibiofilm activity of ZnO-Ag nanoparticles against Pseudomonas aeruginosa

Biofilm-related infections remain a major concern in clinical settings due to the increasing challenge of antimicrobial resistance to conventional antimicrobial treatments. Surface coatings of nanomaterials that can effectively prevent biofilm formation and disrupt established biofilms are essential to addressing this challenge. In this study, a ZnO-Ag nanocomposite was synthesized via a dry chemical method and characterized using XRD, XPS, TEM, SEM-EDX, and AFM, confirming the presence of highly crystalline and pure ZnO and Ag nanoparticles with sharp nanoscale features. The nanocomposite demonstrated potent antibiofilm activity against Pseudomonas aeruginosa, a common Gram-negative biofilm-forming pathogen. Surface-coated glass slides prevented initial biofilm formation, while treatment with higher nanocomposite concentrations (≥ 0.25 g/L) significantly disrupted pre-formed biofilms and altered biofilm architecture, as shown by SEM and crystal violet assays. Mechanistic investigations suggested that nanoparticle surface sharpness may contribute to membrane disruption, and EPR analysis confirmed the generation of reactive oxygen species (ROS), particularly superoxide and methyl radicals, under light exposure. These results highlight the composite's strong potential for integration into surfaces prone to bacterial colonization, offering a practical approach for reducing biofilm-related complications.

The efficacy of nanoparticles on soil microbial biodiversity and the prevention of Fusarium wilt disease (Fusarium oxysporum f.sp. lycopersici)

Fusarium oxysporum f.sp. lycopersici (FOL) wilt endangers Egyptian tomato productivity. Nanotechnology has emerged as an efficient tool for managing plant diseases. This study evaluated salicylic acid nanoparticles (SA-NPs) and glycyrrhizic acid ammonium salt nanoparticles (GAS-NPs) against F. oxysporum in vitro. SA-NPs reduced F. oxysporum growth by 37.8%, and GAS-NPs by 18.9% at 3 ml/L, while SA-NPs at high doses significantly reduced the bacterial count in the tomato rhizosphere. Under greenhouse conditions, high doses of SA-NPs suppressed disease by 73%, compared to 87-93% for other treatments, coinciding with a significant decrease in the overall bacterial count in the tomato rhizosphere. A high dose of SA-NPs reduced heterotrophic, copiotrophic, and fluorescent pseudomonads in the tomato rhizosphere but did not affect the total number of fungi. In vitro, a high dose of both nanoparticles did not significantly reduce bacterial growth in four tested strains: Leclercia adecarboxylata, Pseudomonas putida, Enterobacter ludwigii, and Bacillus marcorestinctum. This suggests that while SA-NP doesn't directly affect bacterial growth, it may interact with tomato roots, indirectly affecting the rhizosphere bacterial population. All treatments increased the expression of ethylene-responsive transcription factor 3 (RAP), xyloglucan endotransglucosylase 2 (XET-2), catalytic hydrolase-2 (ACS-2), phenylalanine ammonia-lyase 5 (PAL5), lipoxygenase D (LOXD), proteinase inhibitor II (PINII), and pathogenesis-related protein 1 (PR1). The highest gene expression levels were obtained from 1 ml/L GAS-NPs and SA-NPs field applications. Furthermore, SA-NPs at 1 ml/L were the most efficient in controlling tomato Fusarium wilt, followed by GAS-NPs. This study investigates the possibility of nanotechnology-based techniques for decreasing Fusarium wilt in tomatoes. However, because of the deleterious impact on the soil bacterial community, high dosages of NPs, particularly SA-NPs, should be applied with caution. Future research should focus on optimizing NPs doses to maintain a balance between efficient disease control and the maintenance of the beneficial complexity of soil microbial biodiversity.

Silver Nanoparticles (AgNPs) from Lysinibacillus sp. Culture Broths: Antibacterial Activity, Mechanism Insights, and Synergy with Classical Antibiotics

Antibiotic-resistant bacteria pose problems for infection prevention and treatment, so developing new procedures or substances against infection is mandatory. Silver nanomaterials are among the more promising antibacterial agents. Herein, we describe the biogenic synthesis of silver nanoparticles (AgNPs) using culture broths from an undescribed species of Lysinibacillus. Culture broths with or without NaCl and from the exponential and stationary growth phases produced four AgNP types. Nanoparticles' shapes were quasi-spherical, with core sizes of 7.5-14.7 nm and hydrodynamic diameters of 48.5-80.2 nm. All the AgNPs contained Ag0 crystals and some AgCl ones. Moreover, their coronas presented different proportions of carbohydrates, proteins, and aliphatic compounds. The AgNPs were good antibacterial agents against six bacterial species, three Gram-positive and three Gram-negative, with MICs of 0.3-9.0 µg/mL. Their activity was higher against the Gram-negative bacteria and particularly against Pseudomonas aeruginosa. These AgNPs acted synergistically with several of the fifteen tested antibiotics. Interestingly, AgNP combinations with some of these inhibited the growth of antibiotic-resistant bacteria, as in the case of S. epidermidis for streptomycin and S. aureus for colistin. The ROS production by E. coli and S. aureus when treated with most AgNPs suggested different mechanisms for bacterial killing depending on the AgNP.

Endophytic fungi-bioinspired nanoparticles potential to control infectious disease

The growing demand for nanomedicine and its potentially diverse biological function required the investigation of raw materials for fabricating the nanomaterial. Current developments have emphasized the implementation of green chemistry to develop metal-oxide and metal nanoparticles. Endophytic fungi have emerged as a potential reservoir of bioactive compounds exemplified by unique structures and influential antibacterial properties. Over the past decade, substantial progress has been achieved in uncovering and profiling these valuable antibacterial compounds. These endophytic fungi-derived bioactive chemicals have diverse applications in various biological properties. Nanoparticle synthesis from materials derived from endophytic fungi, be it whole extracts or pure components, owing to their accessibility, cost-effectiveness in fabrication, material-tissue compatibility, and modest cytotoxicity toward higher organism cells. Nanoparticles from endophytic fungi have been utilized to treat various diseases, including those caused by bacterial, viral, and fungal pathogens. The present review provides a comprehensive discussion of the mechanistic insight into the synthesis and application of endophytic fungi-bioinspired nanoparticles as potential therapeutic agents to control microbial infection. The underlying action mechanism involved in the antimicrobial action of the nanoparticles has also been discussed. The discussion highlights various attributes of nanoparticles that may significantly benefit future researchers as potential therapeutic agents to control microbial infection.

Therapeutic Potential of AgNP-Infused Patches in Periodontal Disease: An Observational Study in Albino Rats

Introduction

Silver nanoparticles (AgNPs) have emerged as a promising therapeutic modality in periodontal disease management due to their potent antimicrobial activity and ability to promote tissue regeneration. This study aimed to evaluate the efficacy of AgNP-infused patches in ligature-induced periodontitis rat model.

Methods

AgNPs were synthesized using a green synthesis method with neem (Azadirachta indica) leaf extract followed by incorporation into polyvinyl alcohol (PVA)-based patches. In vivo efficacy of experimental AgNP patch was tested in albino rats vs marketed formulation and control groups, following ARRIVE guidelines.

Results

Characterization by Atomic Force Microscopy revealed spherical AgNPs with an average size of 85 nm, while Field Emission Scanning Electron Microscopy confirmed uniform morphology and size distribution. Production of microporous AgNP patches with uniform nanoparticle dispersion was also validated by Scanning electron microscopy and Energy Dispersive X-ray Analysis. Observational and histopathological analysis revealed significant improvements in gingival and periodontal tissue restoration, inflammation reduction in the AgNP-treated groups compared to untreated and standard-treated groups.

Discussion

Notably, the high-dose AgNP patch (1000 mg/kg) treated group exhibited near-complete tissue restoration. These findings highlight the potential of AgNP patch as a localized treatment alternative for periodontal disease.

Silver Nanoparticles Functionalized with Polymeric Substances to Reduce the Growth of Planktonic and Biofilm Opportunistic Pathogens

The global rise in antimicrobial resistance, particularly among ESKAPE pathogens, has intensified the demand for alternative therapeutic strategies. Silver nanoparticles (AgNPs) have exhibited broad-spectrum antimicrobial activity and represent a promising approach to combat multidrug-resistant infections. This study aimed to synthesize and functionalize AgNPs using various polymeric agents-ethylene glycol (EG), polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and their combinations-and to evaluate their antimicrobial and antibiofilm efficacy against clinically relevant bacterial strains. AgNPs were synthesized via chemical reduction and functionalized as Ag@EG, Ag@PEG, Ag@EG/PVP, and Ag@PEG/PVP. A total of 68 clinical isolates-including Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus lugdunensis, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa-were tested. Antimicrobial susceptibility was assessed using disc diffusion and broth microdilution assays, while antibiofilm activity was evaluated via the crystal violet method. Among all tested formulations, Ag@EG/PVP exhibited the highest antimicrobial and antibiofilm activity, with notably low minimum inhibitory concentrations (MIC50) and minimum biofilm eradication concentrations (MBEC50) for Ps. aeruginosa and K. pneumoniae. In contrast, AgNPs functionalized with PEG or EG alone showed limited efficacy. Biofilm-forming isolates, particularly Staphylococcus spp., required higher concentrations for inhibition. These results highlight the critical role of functionalization in modulating the antimicrobial properties of AgNPs, with Ag@EG/PVP demonstrating potent activity against both planktonic and biofilm-associated multidrug-resistant bacteria. Overall, this study supports further developing AgNPs-based formulations as adjuncts or alternatives to conventional antibiotics, particularly for managing biofilm-related infections. Future research should focus on formulation optimization, safety assessment, and translational potential.

Antibacterial Activity of GO-Based Composites Enhanced by Phosphonate-Functionalized Ionic Liquids and Silver

The development of antibiotic-independent antimicrobial materials is critical for addressing bacterial resistance to conventional antibiotics. Currently, there is a lack of comprehensive understanding of ionic liquid-modified composites in antimicrobial applications. Here, we innovatively prepared GO-based composites modified with phosphonate ionic liquids via a series of surface functionalizations. The resulting antibacterial composites exhibit significant broad-spectrum activity against both Gram-negative and Gram-positive bacteria, including drug-resistant strains, with stronger efficacy against Gram-negative species. Additionally, the material features excellent long-term reusability and the ability to inhibit/destroy biofilms, which is vital for combating persistent infections. Mechanistic studies reveal its antibacterial effects through multiple pathways: disrupting bacterial membranes, inducing ROS, and inactivating intracellular substances-mechanisms less likely to promote resistance. Overall, these phosphonate ionic liquid-modified polycationic materials demonstrate substantial potential in treating bacterial infections, offering a promising strategy to tackle antibiotic resistance challenges.

Silver Nanoparticles and Antibiotics: A Promising Synergistic Approach to Multidrug-Resistant Infections

The escalating threat of antibiotic resistance demands innovative strategies against multidrug-resistant (MDR) microorganisms, particularly in hospital settings where such infections represent a major global health challenge. Since the rapid growth of nanotechnology interdisciplinary research and funding programs in the 2000s, silver ions have re-emerged as potent antimicrobial agents, offering a promising complement to conventional therapies. This therapeutic potential is nowadays explored through the use of silver nanoparticles (AgNPs) as sources for silver ions release. Recent studies have shown that controlled silver ion release enhances the efficacy of common antibiotics. This can be attributed to the energetically demanding nature of the bacterial response to silver, which weakens bacterial metabolism and, in turn, overwhelms bacterial defenses and increases antibiotic effectiveness. Herein, historical insights into the use of colloidal silver and AgNPs are combined with a review of recent research on the exploitation of the synergistic effect between AgNPs and antibiotics as a promising strategy against MDR pathogens.

Recent Advances and Challenges for Biological Materials in Micro/Nanocarrier Synthesis for Bone Infection and Tissue Engineering

Roughly 1.71 billion people worldwide suffer from large bone abnormalities, which are the primary cause of disability. Traditional bone grafting procedures have several drawbacks that impair their therapeutic efficacy and restrict their use in clinical settings. A great deal of work has been done to create fresh, more potent strategies. Under these circumstances, a crucial technique for the regeneration of major lesions has emerged: bone tissue engineering (BTE). BTE involves the use of biomaterials that can imitate the natural design of bone. To yet, no biological material has been able to fully meet the parameters of the perfect implantable material, even though several varieties have been created and investigated for bone regeneration. Against this backdrop, researchers have focused a great deal of interest over the past few years on the subject of nanotechnology and the use of nanostructures in regenerative medicine. The ability to create nanoengineered particles that can overcome the current constraints in regenerative strategies─such as decreased cell proliferation and differentiation, insufficient mechanical strength in biological materials, and insufficient production of extrinsic factors required for effective osteogenesis has revolutionized the field of bone and tissue engineering. The effects of nanoparticles on cell characteristics and the application of biological materials for bone regeneration are the main topics of our review, which summarizes the most recent in vitro and in vivo research on the application of nanotechnology in the context of BTE.

Synergistic Activity of Gloeophyllum striatum-Derived AgNPs with Ciprofloxacin and Gentamicin Against Human Pathogenic Bacteria

Silver nanoparticles (AgNPs) are used in a variety of different fields due to their excellent antimicrobial potential. Despite clear advantages, concerns about their toxicity have arisen, also concerning biogenic nanoparticles. Simultaneously, global healthcare is facing a problem of spreading antimicrobial resistance towards existing antibiotics. Using combined therapies involving AgNPs and antibiotics seems to be a promising solution to the above problems. The aim of this study was to evaluate the enhancement of the effectiveness of AgNPs, ciprofloxacin, and gentamicin against Staphylococcus aureus and Pseudomonas aeruginosa. The research involved the assessment of antimicrobial and antibiofilm-forming activities and the analysis of phospholipid and fatty acid profiles. Our results showed that combining the tested antimicrobials can enhance their activity against the tested bacterial strains. However, no effect was observed while mixing AgNPs with ciprofloxacin against P. aeruginosa. The most significant effect was obtained by combining 3.125 µg/mL of AgNPs with 0.125 µg/mL of gentamicin against S. aureus. It was also shown that the tested antimicrobials applied in combination exhibited an increased inhibitory activity towards bacterial biofilm formation by S. aureus. Lipidomic analysis revealed that under the influence of the tested antimicrobials, the properties of the cell membrane were altered in different ways depending on the bacterial strain.

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.

Nanoparticles as tools for enhancing plant resistance to biotic stress in the context of climate change

In the face of climate change, agriculture is increasingly challenged by shifting dynamics of biotic stresses, including the intensified spread of pests and pathogens. Traditional control methods, often reliant on chemical pesticides, are associated with environmental degradation and potential health risks. Nanoparticles (NPs) present a promising, sustainable alternative for enhancing plant resistance to biotic stresses, potentially revolutionizing agricultural practices. This mini-review explores the mechanisms through which NP-based formulations (such as metal-based NPs, chitosan, and silica) induce plant responses and bolster defences against pathogens and pests. By enhancing plant resilience without the environmental downsides of conventional pesticides, NPs could support a more sustainable approach to crop protection. This review also highlights the potential risks in expanding the use of NPs in agriculture, urging more studies to explore these technologies as a sustainable approach to managing crops in a changing climate.

Biofilm suppression of Pseudomonas aeruginosa by bio-engineered silver nanoparticles from Hellenia speciosa rhizome extract

Bacterial biofilm, a persistent issue in healthcare equipment and typical infections, is exacerbated by the pathogenesis and antibiotic tolerance of Pseudomonas aeruginosa. This bacterium remains a significant concern in the global healthcare sector. Silver nanoparticles, with their potent antibacterial properties, have emerged as a promising solution. This study, therefore, is of utmost importance as it aims to delve into the parameters influencing the biogenic nanoparticle-assisted regulation of bacterial adherence by Pseudomonas aeruginosa. The nano-sized particles were bioengineered using Hellenia speciosa rhizome extracts, which mainly included biologically active components such as mequinol, 4-hydroxy-3-methylacetophenone, and phenol, 2,6-dimethoxy, supplemented with the formation of silver nanostructured materials. The nanoclusters were characterized by UV-Vis spectrophotometry, X-ray scattering, and scanning electron microscopy (SEM). According to a microtiter plate experiment, the nanoparticle degraded biofilms up to 94.41 % at dosages varied from 0 to 25 μg/ml. The light microscopy study and the interface architecture of biofilm suppression by electron microscopy demonstrated the nano-sized particle's potential to prevent bacterial adherence.

Green Fabrication of Silver Nanoparticles, Statistical Process Optimization, Characterization, and Molecular Docking Analysis of Their Antimicrobial Activities onto Cotton Fabrics

Nanotechnological methods for creating multifunctional fabrics are attracting global interest. The incorporation of nanoparticles in the field of textiles enables the creation of multifunctional textiles exhibiting UV irradiation protection, antimicrobial properties, self-cleaning properties and photocatalytic. Nanomaterials-loaded textiles have many innovative applications in pharmaceuticals, sports, military the textile industry etc. This study details the biosynthesis and characterization of silver nanoparticles (AgNPs) using the aqueous mycelial-free filtrate of Aspergillus flavus. The formation of AgNPs was indicated by a brown color in the extracellular filtrate and confirmed by UV-Vis spectroscopy with a peak at 426 nm. The Box-Behnken design (BBD) is used to optimize the physicochemical parameters affecting AgNPs biosynthesis. The desirability function was employed to theoretically predict the optimal conditions for the biosynthesis of AgNPs, which were subsequently experimentally validated. Through the desirability function, the optimal conditions for the maximum predicted value for the biosynthesized AgNPs (235.72 µg/mL) have been identified as follows: incubation time (58.12 h), initial pH (7.99), AgNO3 concentration (4.84 mM/mL), and temperature (34.84 °C). Under these conditions, the highest experimental value of AgNPs biosynthesis was 247.53 µg/mL. Model validation confirmed the great accuracy of the model predictions. Scanning electron microscopy (SEM) revealed spherical AgNPs measuring 8.93-19.11 nm, which was confirmed by transmission electron microscopy (TEM). Zeta potential analysis indicated a positive surface charge (+1.69 mV), implying good stability. X-ray diffraction (XRD) confirmed the crystalline nature, while energy-dispersive X-ray spectroscopy (EDX) verified elemental silver (49.61%). FTIR findings indicate the presence of phenols, proteins, alkanes, alkenes, aliphatic and aromatic amines, and alkyl groups which play significant roles in the reduction, capping, and stabilization of AgNPs. Cotton fabrics embedded with AgNPs biosynthesized using the aqueous mycelial-free filtrate of Aspergillus flavus showed strong antimicrobial activity. The disc diffusion method revealed inhibition zones of 15, 12, and 17 mm against E. coli (Gram-negative), S. aureus (Gram-positive), and C. albicans (yeast), respectively. These fabrics have potential applications in protective clothing, packaging, and medical care. In silico modeling suggested that the predicted compound derived from AgNPs on cotton fabric could inhibit Penicillin-binding proteins (PBPs) and Lanosterol 14-alpha-demethylase (L-14α-DM), with binding energies of -4.7 and -5.2 Kcal/mol, respectively. Pharmacokinetic analysis and sensitizer prediction indicated that this compound merits further investigation.

Therapeutic Potential of Silver Nanoparticles (AgNPs) as an Antimycobacterial Agent: A Comprehensive Review

The uncontrolled emergence of multidrug-resistant mycobacterial strains presents as the primary determinant of the present crisis in antimycobacterial therapeutics and underscores tuberculosis (TB) as a daunting global health concern. There is an urgent requirement for drug development for the treatment of TB. Numerous novel molecules are presently undergoing clinical investigation as part of TB drug development. However, the complex cell wall and the lifecycle of M. tuberculosis within the host pose a significant challenge to the development of new drugs and, therefore, led to a shift in research focus towards alternative antibacterial compounds, notably nanotechnology. A novel approach to TB therapy utilizing silver nanoparticles (AgNPs) holds the potential to address the medical limitations imposed by drug resistance commonly associated with currently available antibiotics. Their broad-spectrum antimicrobial activity presents the utilization of AgNPs as a promising avenue for the development of therapeutics targeting mycobacterial-induced diseases, which can effectively target Mycobacterium tuberculosis, including drug-resistant strains. AgNPs can enhance the effectiveness of traditional antibiotics, potentially leading to better treatment outcomes and a shorter duration of therapy. However, the successful implementation of this complementary strategy is contingent upon addressing several pivotal therapeutic challenges, including suboptimal delivery, variability in intra-macrophagic antimycobacterial effect, and potential toxicity. Future perspectives may involve developing targeted delivery systems that maximize therapeutic effects and minimize side effects, as well as exploring combinations with existing TB medications to enhance treatment outcomes. We have attempted to provide a comprehensive overview of the antimycobacterial activity of AgNPs, and critically analyze the advantages and limitations of employing silver nanoparticles in the treatment of TB.