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A highly efficient, novel, two‐phase liquid method using phase transfer catalyst is reported to prepare β‐lactam‐conjugated silver nanoparticles as an approach to improve antibacterial activity of β‐lactams. In the method assisted by cetyltrimethylammonium bromide, NaBH4 reduced AgNO3 producing silver NPs that are coated with β‐lactams. The studies conducted provide a generalized method applicable to all types of β‐lactam substrates for capping on silver NPs. The NPs have been characterized by UV–Visible, Fourier transform infrared spectroscopy, x‐ray diffraction, transmission electron microscopy, and dynamic light scattering methods. [ABSTRACT FROM AUTHOR]

The use of plants in the biological production of silver nanoparticles for antibacterial applications is a growing field of research. In the current work, we formulated Ocimum kilimandscharicum extracts using silver nanoparticles, and evaluated its potential antibacterial activity. Aqueous and methanol plant extracts were used to reduce silver nitrate at different time intervals (30 to 150 minutes) and pH (2 to 11). The UV-visible absorption spectrum recorded for methanol and aqueous extracts revealed a successful synthesis of AgNPs for methanol and aqueous extracts. The antimicrobial activity of the AgNPs was evaluated against Escherichia coli ATCC 25922, Salmonella choleraesuius ATCC 10708, and Staphylococcus aureus ATCC 25923 The best inhibition zone for the methanol and aqueous-mediated AgNPs, ranging from 12 ± 1 to 16 ± 1mm. Additionally, the methanol and aqueous extract silver nanoparticles had the same Minimum Inhibitory Concentration (6.25 ± 0.00 mg/ml), whereas the Minimum Bactericidal Concentrations were 12.5 ± 0.00 and 25 ± 0.00 mg/ml, respectively. The highest inhibition zone of 16 ± 1 mm was observed against Salmonella choleraesuius with 50 ± 0.00 mg/ml aqueous silver nanoparticles. The results show that the silver nanoparticles made with Ocimum kilimandscharicum have antibacterial action against those microorganisms. [ABSTRACT FROM AUTHOR]

Metal and metal oxide nanostructured materials have been chemically and physically characterized and tested concerning methylene blue (MB) photoremoval and UV antibacterial activity against Escherichia coli and Staphylococcus aureus. In detail, silver nanoparticles and commercial BaTiO3 nanoparticles were modified to obtain nanocomposites through sonicated sol–gel TiO2 synthesis and the photodeposition of Ag nanoparticles, respectively. The characterization results of pristine nanomaterials and synthetized photocatalysts revealed significant differences in specific surface area (SSA), the presence of impurities in commercial Ag nanoparticles, an anatase phase with brookite traces for TiO2-based nanomaterials, and a mixed cubic–tetragonal phase for BaTiO3. Silver nanoparticles exhibited superior antibacterial activity at different dosages; however, they were inactive in the photoremoval of the dye. The silver–TiOx nanocomposite demonstrated an activity in the UV photodegradation of MB and UV inhibition of bacterial growth. Specifically, TiO2/AgNP (30–50 nm) reduced growth by 487.5 and 1.1 × 103 times for Escherichia coli and Staphylococcus aureus, respectively, at a dose of 500 μg/mL under UV irradiation. [ABSTRACT FROM AUTHOR]

Infections related to biomedical devices and materials remain a critical healthcare concern, leading to considerable morbidity and disease burden. To combat this issue, the development of fibers with inherent antibacterial properties has garnered significant interest. These fibers offer a large surface area, making them ideal candidates for effective treatment with antibacterial agents. In this study, we present a straightforward procedure for applying silver nanoparticles (AgNPs) to hydrophobic polylactic acid (PLA) fibers that have been surface-modified using sodium hydroxide (NaOH). The method involved electrospinning to create a high-thickness web of PLA fibers, followed by gradual surface modification with NaOH at two different concentrations (0.5 M and 1 M). To confer antibacterial properties to the modified surface samples, we applied silver nanoparticles (AgNPs) at a concentration of 25 mM. In contrast to regular PLA fibers, the surfaces of hydrolyzed PLA (PLA-H) fibers, AgNPs-treated PLA (PLA-A), and hydrolyzed-AgNPs coated PLA (PLA-H-A) fibers exhibited a non-uniform and highly porous structure. EDX analysis provided crucial information about the presence and integration of Ag nanoparticles into the PLA fibers. The PLA-H-A sample exhibited the highest hydrophilicity, with a contact angle of 65.7°. Additionally, the results from differential scanning calorimetry indicated an increase in PLA-H-A's glass transition temperature. Notably, in the Gram-positive Escherichia coli (E. coli) and Gram-negative Staphylococcus aureus (S. aureus) tests, the PLA-H-A samples demonstrated highly effective antibacterial properties, effectively preventing bacterial growth. [ABSTRACT FROM AUTHOR]

Bacterial infection is a thorny problem, and it is of great significance to developing green and efficient biological antibacterial agents that can replace antibiotics. This study aimed to rapidly prepare a new type of green antibacterial nanoemulsion containing silver nanoparticles in one step by using Blumea balsamifera oil (BBO) as an oil phase and tea saponin (TS) as a natural emulsifier and reducing agent. The optimum preparation conditions of the AgNPs@BBO-TS NE were determined, as well as its physicochemical properties and antibacterial activity in vitro being investigated. The results showed that the average particle size of the AgNPs@BBO-TS NE was 249.47 ± 6.23 nm, the PDI was 0.239 ± 0.003, and the zeta potential was −35.82 ± 4.26 mV. The produced AgNPs@BBO-TS NE showed good stability after centrifugation and 30-day storage. Moreover, the AgNPs@BBO-TS NE had an excellent antimicrobial effect on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. These results demonstrated that the AgNPs@BBO-TS NE produced in this study can be used as an efficient and green antibacterial agent in the biomedical field. [ABSTRACT FROM AUTHOR]

Polymer-based sponges loaded with antibacterial agents are potential wound dressings ideal for treating bacteria-infected wounds. Gelatin/poly (ethylene glycol) (PEG) sponge-based wound dressings loaded with metronidazole and Ag nanoparticles with different degrees of cross-linking were prepared, and their capability to treat infected wounds in vitro was evaluated. The degree of cross-linking of the sponges varied, and the porosity of the sponges was in the range of 15.64–91.10%. The amount of gelatin used to prepare the sponges influenced the porosity of the sponges. The sponges displayed an initial burst drug release of metronidazole followed by a sustained release profile. The sponges exhibited considerable antibacterial activity against Gram-positive and Gram-negative bacteria. The % cell viability of the sponges was in the range of 71.17–86.10%, indicating distinguished biocompatibility. The in vitro experiment showed that the sponge loaded with metronidazole, SAM2%, displayed a significant reduction of 66.68% in the scratch area compared to the sponge loaded with a combination of silver nanoparticles and metronidazole with a closure rate of 46.61% at 96 h. The promising features of the sponges indicate that they are potential wound dressings for treating infected wounds. [ABSTRACT FROM AUTHOR]

This study defined a facile, inexpensive, and benign method to fabricate silver nanoparticles (AgNPs) using Tradescantia pallidum var. purpurea aqueous leaves extract for the first time. A UV–vis spectrum showed that the evaluated extract was promising for green synthesis of the SNP, with the highest peak of absorption between 450 and 550 nm. The phytochemicals present in the plant extract acts as capping and stabilization agent were confirmed by FTIR analysis. EDX proved the presence of Ag while SEM confirmed the AgNPs with the spherical shape. TEM revealed the average particle size was 23 nm. Additionally, AgNPs exhibited significant antibacterial activity and turbidimetry analysis showed MIC and MBC was in range of 25–100 µg/mL against both Gram positive and Gram-negative bacteria in Luria Bertani broth cultures. The AgNPs exhibited potent antibacterial activity against gram-positive bacteria, with a ZOI of 12 ± 0.25 mm produced against BacillusB subtilis showed the largest zones of inhibition, which were greater than the positive control (cefotaxime). The MIC values were 50 µg/mL for Pseudomonas aeruginosa, 25 µg/mL for Staphylococcus aureus and Escherichia coli, and 100 µg/mL for B. subtilis, confirming their significant antibacterial action. AgNPs inhibited the DDPH free radical scavenging activity with an IC50 = 91.87 µg/mL. It is believed that these AgNPs play a crucial role in determining the therapeutic potential of T. pallida due to their biological efficacy. [ABSTRACT FROM AUTHOR]

Silver-based antibacterial coatings limit the spread of hospital-acquired infections. Indeed, the use of silver and silver oxide nanoparticles (Ag and AgO NPs) incorporated in amorphous hydrogenated carbon (a-C:H) as a matrix demonstrates a promising approach to reduce microbial contamination on environmental surfaces. However, its success as an antibacterial coating hinges on the control of Ag+ release. In this sense, if a continuous release is required, an additional barrier is needed to extend the release time of Ag+. Thus, this research investigated the use of a plasma fluoropolymer (CFx) as an additional top layer to elongate Ag+ release and increase the antibacterial activity due to its high hydrophobic nature. Herein, a porous CFx film was deposited on a-C:H containing Ag and AgO NPs using pulsed afterglow low pressure plasma polymerization. The chemical composition, surface wettability and morphology, release profile, and antibacterial activity were analyzed. Overall, the combination of a-C:H:Ag (12.1 at. % of Ag) and CFx film (120.0°, F/C = 0.8) successfully inactivated 88% of E. coli and delayed biofilm formation after 12 h. Thus, using a hybrid approach composed of Ag NPs and a hydrophobic polymeric layer, it was possible to increase the overall antibacterial activity of the coating. [ABSTRACT FROM AUTHOR]

Aims To evaluate the effect of silver nanoparticles alone and in combination with Triclosan, and trans -cinnamaldehyde against Staphylococcus aureus and Escherichia coli biofilms on sutures to improve patients' outcomes. Methods and results Silver nanoparticles were prepared by chemical method and characterized by UV–visible spectrophotometer and dynamic light scattering. The minimum inhibitory concentration was assessed by the Microdilution assay. The antibiofilm activity was determined using crystal violet assay. A checkerboard assay using the fractional inhibitory concentration index and time-kill curve was used to investigate the synergistic effect of silver nanoparticle combinations. The hemolytic activity was determined using an erythrocyte hemolytic assay. Our results revealed that silver nanoparticles, Triclosan, and trans- cinnamaldehyde (TCA) inhibited S.aureus and E.coli biofilms. Silver nanoparticles with TCA showed a synergistic effect (FICI values 0.35 and 0.45 against S. aureus and E. coli biofilms, respectively), and silver nanoparticles with Triclosan showed complete inhibition of S. aureus biofilm. The hemolytic activity was <2.50% for the combinations. [ABSTRACT FROM AUTHOR]

This research explores the eco-friendly synthesis of silver nanoparticles (AgNPs) using Cassia occidentalis L. seed extract. Various analytical techniques, including UV–visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDX), were employed for comprehensive characterization. The UV–visible spectra revealed a distinct peak at 425 nm, while the seed extract exhibited peaks at 220 and 248 nm, indicating the presence of polyphenols and phytochemicals. High-resolution TEM unveiled spherical and oval-shaped AgNPs with diameters ranging from 6.44 to 28.50 nm. The SEM exhibiting a spherical shape and a polydisperse nature, thus providing insights into the morphology of the AgNPs. EDX analysis confirmed the presence of silver atoms at 10.01% in the sample. XRD results unequivocally confirm the crystalline nature of the AgNPs suspension, thereby providing valuable insights into their structural characteristics and purity. The antioxidant properties of AgNPs, C. occidentalis seed extract, and butylated hydroxytoluene (BHT) were assessed, revealing IC50 values of 345, 500, and 434 μg/mL, respectively. Antibacterial evaluation against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli demonstrated heightened sensitivity of bacteria to AgNPs compared to AgNO3. Standard antibiotics, tetracycline, and ciprofloxacin, acting as positive controls, exhibited substantial antibacterial efficacy. The green-synthesized AgNPs displayed potent antibacterial activity, suggesting their potential as a viable alternative to conventional antibiotics for combating pathogenic bacterial infections. Furthermore, potential biomedical applications of AgNPs were thoroughly discussed. [ABSTRACT FROM AUTHOR]

Silver nanoparticles have shown inhibitory capabilities and its use in battling viral infections are strengthened by its potent antibacterial activity. Notably, since it directly affects antiviral efficacy, the proper choice of synthesis process for making silver nanoparticles is a vital element to be taken into consideration. The synthesis of silver nanoparticles for the treatment of viral and bacterial infections involves creating silver particles at the nanoscale with unique antimicrobial properties. Various methods exist for synthesizing silver nanoparticles, including chemical reduction, green synthesis, and physical methods. Chemical reduction involves using reducing agents to convert silver ions into silver nanoparticles. Green synthesis employs reducing agents in an environmentally friendly manner. Physical methods rely on techniques such as laser ablation or thermal evaporation to produce silver nanoparticles. In order to provide technological guidance for choosing antiviral silver nanoparticle manufacturing methods, this paper introduces and explores alternative synthesis methods for creating silver nanoparticles. [ABSTRACT FROM AUTHOR]

The synthesis of Cyanobacteria‐mediated nanoparticles has attracted great attention due to its ecofriendly, cost‐effective and biocompatible properties. Silver nanoparticles (AgNPs) are used in different areas such as medicine, household products, disinfectants or food storage. The present study aimed the biosynthesis of AgNPs from Cyanobacterial Chroococcus sp. and their antimicrobial activities on some important pathogen bacterial species. According to the obtained data, optimal conditions for synthesis of AgNPs were extract rate 3 : 1 v/v (cell extract/AgNO3), silver salt concentration 10 mM, pH 7, temperature 60 °C and time 30 minutes. The surface plasmon resonance peak of AgNPs was observed at 420–430 nm, and AgNPs were well‐dispersed spherical with an average size of 11–13 nm in diameter by TEM. SEM‐EDX analysis revealed a strong signal of silver. With FTIR analyzes, shift in the absorption bands after the AgNPs formation was confirmed. X‐ray diffraction analysis exhibited that the AgNPs were cubic crystalline shape. Zeta potential of AgNPs showed ‐ 20 mV. The AgNPs strong showed antibacterial activity on an opportunistic bacterial pathogens of Micococcus luteus, Bacillus subtilis and Pseudomonas aeroginosa. The effective and rapid synthesis of Chroococcus‐mediated AgNPs and their strong antimicrobial effects can create an important potential for their use in biomedical and environmental applications. [ABSTRACT FROM AUTHOR]

Indeed, considerable efforts have been made in the domain of silver nanoparticles, including the construction and wide‐ranging applications. This work involves the synthesis and characterization of salophen anchored silver nanoparticles (AgNPs), and its utilization for selective detection of Fe2+ and Cu2+ ions in DMSO. These AgNPs were synthesized by the reduction of Ag+ ions with salophen ligand, and were characterized by different techniques which include UV‐visible, fluorescence, FTIR, SEM, EDX, TEM, PXRD, DLS, and zeta potential. The negative zeta potential value of −19.6 mV evidenced the stability of the AgNPs. These AgNPs were found to sense Fe2+ and Cu2+ ions selectively in DMSO solution at various concentrations. Instant color change from olive to brown as well as olive to light olive was observed while detecting Fe2+ and Cu2+ ions by the nanoprobe, respectively. UV‐visible and fluorescence spectroscopic investigations were carried out to establish the sensing ability of the nanoprobe. Additionally, AgNPs revealed promising antibacterial activity selectively against gram‐negative bacteria over gram‐positive bacteria. Thus, our approach opens up a new track to design novel and operative functionalized nanomaterials for real‐life sensing and biomedical applications. [ABSTRACT FROM AUTHOR]

OBJECTIVE To establish the lowest effective dose of commercially available nanoparticulate silver (AgNP) for antibacterial activity against Escherichia coli (E coli) and methicillin-resistant Staphylococcus pseudintermedius (MRSP), in vitro, and to establish the effect of incorporating AgNP into carriers for sustained release on this antibacterial activity. SAMPLES Silver nanoparticle dispersion (0.02 mg/mL) composed of citrate-stabilized, spherical, 10 nm diameter nanoparticles in aqueous buffer. PROCEDURES E coli and MRSP were treated with 0.01 mg/mL AgNP. The highest concentration of bacteria where growth was inhibited by AgNP was selected for treatment with 0.01 mg/mL AgNP incorporated 3 carriers for sustained release: calcium sulfate hemihydrate (CSH) beads, poloxamer 407 gel, and gelatin sponge, respectively. The antibacterial activity of AgNP and AgNP incorporated into carriers for sustained release was compared with a mixed linear effects model. RESULTS AgNP inhibited bacterial growth at a concentration of 101 for MRSP and 103 for E coli. For MRSP, the treatment group was associated with bacterial growth (P < .001) while the concentration of bacteria and time were not (P = .292 and P = .289, respectively). For E coli, the treatment group and concentration of bacteria were associated with bacterial growth (P < .001 and = .029, respectively) while time was not (P = .095). Poloxamer 407 gel exerted standalone antibacterial activity against both species of bacteria; sponge and CSH beads did not. CLINICAL RELEVANCE AgNP has antibacterial activity against E coli and MRSP, which can be reduced when incorporated into carriers for sustained release. Poloxamer 407 gel alone and combined with AgNP exerts antibacterial activity against E coli and MRSP. [ABSTRACT FROM AUTHOR]

The global increase in multidrug-resistant bacteria poses a challenge to public health and requires the development of new antibacterial materials. In this study, we examined the bactericidal properties of mesoporous silica-coated silver nanoparticles, varying the core sizes (ca. 28 nm and 51 nm). We also investigated gold nanoparticles (ca. 26 nm) coated with mesoporous silica as possible inert metal cores. To investigate the modification of antimicrobial activity after the surface charge change, we used silver nanoparticles with a silver core of 28 nm coated with a mesoporous shell (ca. 16 nm) and functionalized with a terminal amine group. Furthermore, we developed a facile method to create mesoporous silica-coated silver nanoparticles (Ag@mSiO2) doped films using polyurethane (IROGRAN®) as a polymer matrix via solution casting. The antibacterial effects of silver nanoparticles with different core sizes were analyzed against Gram-negative and Gram-positive bacteria relevant to the healthcare and food industry. The results demonstrated that gold nanoparticles were inert, while silver nanoparticles exhibited antibacterial effects against Gram-negative (Escherichia coli and Salmonella enterica subsp. enterica serovar Choleraesuis) and Gram-positive (Bacillus cereus) strains. In particular, the larger Ag@mSiO2 nanoparticles showed a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) of 18 µg/mL in the Salmonella strain. Furthermore, upon terminal amine functionalization, reversing the surface charge to positive values, there was a significant increase in the antibacterial activity of the NPs compared to their negative counterparts. Finally, the antimicrobial properties of the nanoparticle-doped polyurethane films revealed a substantial improvement in antibacterial efficacy. This study provides valuable information on the potential of mesoporous silica-coated silver nanoparticles and their applications in fighting multidrug-resistant bacteria, especially in the healthcare and food industries. [ABSTRACT FROM AUTHOR]

Electrospun polymeric nanofibers incorporated with some medicines or biologically active nanoparticles have a huge range of various applications in biomedical fields such as wound dressing, drug delivery, and tissue engineering. Blending several polymers with different properties allows one to obtain a new material with improved physicochemical and mechanical characteristics, as well as to control the incorporation and release of medical agents, including antimicrobial, antifungal, and other substances. In this work, a novel approach to prepare a blend of two polymers [polyvinylpyrrolidone (PVP) and polymethyl methacrylate (PMMA)] to produce biocompatible nanofibers with incorporated antibacterial agents — phenylalanine or silver nanoparticles is proposed. The diameter of the obtained nanofibers is in the range of 2–4 μm. Antimicrobial agents are incorporated in PVP in an aqueous solution, then the prepared adduct is dried and mixed with PMMA in an organic solvent. In this nanofiber mat, PMMA provides the mechanical strength of the mat and assists in the gradual release of the antimicrobial agents. The formation of the PVP:PMMA nanofibers with incorporated antimicrobial agents at different stages was monitored by spectroscopy. The release of antimicrobial agents from the nanofibers mat during wetting was studied and confirmed by spectroscopy and mass spectrometry investigations. [ABSTRACT FROM AUTHOR]

Antibacterial resistance among uro-pathogens has become a global issue for bacterial infection treatment. The antibacterial activity of various plant extracts and silver nanoparticles (AgNPs) derived from medicinal plant extract was evaluated against different drug-resistant uro-pathogens isolated from clinical patients by Agar Well Diffusion and Minimum Inhibitory Concentration (MIC) assays. A total of 100 urine samples were collected from patients admitted to the hospital followed by the identification of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Proteus mirabilis, Enterobacter aerogenes, and Klebsiella pneumonia through colony morphology, gram staining, and biochemical characterization. All isolates were highly resistant to all the tested drugs except Amikacin, Gentamicin, and Imipenem. Organic extracts of clove have potent antibacterial activity against all drug-resistant isolates. Interestingly P. aeruginosa was sensitive to all inorganic extracts. These results revealed that the organic extracts of medicinal plants showed more consistent antimicrobial activity compared to their aqueous fraction. Furthermore, the green synthesis of AgNPs derived from clove extract showed strong activity against all tested pathogens followed by green synthesis of AgNPs derived from garlic, ginger, kalwonji, turmeric, and thymus extract respectively compared to medicinal plant extract. Moreover, MIC results showed that AgNPs derived from medicinal plant extract indicate higher efficiency in inhibiting bacterial growth than the medicinal plant extract. The current finding shows that AgNPs derived from plant extract can be recommended as a good alternative for treating the resistant uro-pathogens strains as compared to synthetic drugs and will be considered an attractive candidate for future biological applications. [ABSTRACT FROM AUTHOR]

Our aims in this work are the preparation of an ionic liquid based on heterocyclic compounds with Ag nanoparticles and the investigation of its application as an antibacterial and anticandidal agent. These goals were achieved through the fabrication of an ionic liquid based on Ag nanoparticles with 5-Amino-3-(4-fluorophenyl)-N-hexadecyl-7-(4-methylphenyl)-2-H spiro[cyclohexane1,2'-[1,3]thiazolo [4,5-b]pyridine]-6-carbonitrile (P16). The nanostructure of the prepared ionic liquid was characterized using techniques such as FTIR, 1HNMR, 13CNMR, UV, SEM, and TEM. The biological activity of the prepared compound (P16) and its nanocomposites with Ag nanoparticles was tested using five clinical bacteria (Pseudomonas aeruginosa 249; Escherichia coli 141; Enterobacter cloacae 235; Staphylococcus epidermidis BC 161, and methicillin-resistant S. aureus 217), and three Candida species (Candida utilis ATCC 9255; C. tropicalis ATCC 1362, and C. albicans ATCC 20402). The FTIR, 1HNMR, and 13CNMR results confirmed the chemical structure of the synthesized P16 compound. The nanostructure of the prepared ionic liquid was determined based on data obtained from the UV, SEM, and TEM tests. The antibacterial and anticandidal results showed that the biological activity of the compound (P16) was enhanced after the formation of nanocomposite structures with Ag nanoparticles. Moreover, the biological activity of the compound itself (P16) and that of its nanocomposite structure with Ag nanoparticles was higher than that of ampicillin and amphotericin B, which were used as control drugs in this work. [ABSTRACT FROM AUTHOR]

The current study explored the use of the ethanolic extract of Enteromorpha intestinalis to determine its capability to synthesize silver nanoparticles. The GC-mass technique was utilized to identify the active compounds in the algal ethanolic extract. The extract's potential in fabricating silver nanoparticles was tested, and their formation was inferred through the color change of the mixture from light green to dark brown. The synthesized nanoparticles were characterized using various techniques, (FTIR) spectroscopy, a scanning electron microscope (SEM), and an energy-dispersive X-ray spectroscopy (EDX). In addition, they were analyzed using X-ray diffraction (XRD). The antibacterial effectiveness was tested through the agar well diffusion method. The GC-mass results showed that the ethanolic extract contained several active compounds, including nhexadecanoic acid (37.40%), neophytadiene (11.08%), 9,12,15-octadecatrienoic acid, (Z, Z, Z)-(17.32%), and oleic acid (10.28%). A peak at 435nm in the UV-vis absorption spectrum confirmed the formation of silver nanoparticles. The XRD technique determined the crystalline nature of the silver nanoparticles, and SEM results showed that they had spherical shapes with sizes ranging between 47-78nm. EDX analysis revealed that the synthesized silver nanoparticles comprised silver, carbon, oxygen, and chlorine. The efficacy of the synthesized silver nanoparticles was tested against four types of pathogenic bacteria, namely E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. The results demonstrated that the silver nanoparticles had a significant inhibitory capability against these pathogens. [ABSTRACT FROM AUTHOR]

The introduction of nanotechnology in the food industry has created several opportunities for this sector. Several recent advancements in food packaging use nanotechnology to enhance the function and quality of the packaging materials. This review focuses on how various nanomaterials used in different packaging materials help in maintaining the quality and shelf life of the food product. Several applications of nanomaterials in food packaging such as the use of silver nanoparticles as powerful antibacterial agents, polymer/clay nanocomposites as high barrier packaging materials, and nanosensors were mentioned here. The advances in food nanopackaging, including improved, active, smart, and bio-based packaging, were also discussed. The bio-based packaging offers a substitute for the most widely used non-degradable polymer substances. This review paper aims to highlight some of the most recent technological developments with the use of nanotechnology in the food industry and to indicate some of the many potential future research directions. [ABSTRACT FROM AUTHOR]

The synthesis of metal nanoparticles through the use of plant extract is a process that is not only simple but also inexpensive, quick, and favorable to the environment. As a result, it is utilized in a wide variety of fields. When synthesizing silver nanoparticles (AgNPs), several different kinds of plant extracts were utilized. The manufacture of silver nanoparticles was carried out in this study using an environmentally friendly technique. The aqueous extract of the Aloe fleurentinorum plant was utilized as a stabilizing and reducing agent. To determine the optimal conditions for the synthesis of silver nanoparticles, it was necessary to investigate the impact of several parameters on the process. These parameters included the reactant volume ratio, pH values, temperature, and reaction time. To get crystallite and stable silver nanoparticles, an aqueous solution of AgNO3 (0.01M) was added to an aqueous extract of Aloe fleurentinorum plant at a temperature of 60 degrees Celsius and a pH of 8. The mixture was then stirred with a magnetic stirrer for ninety minutes (90 minutes). Using a variety of methods (UV-vis spectrophotometer, FTIR, XRD, SEM, EDX, and XPS), several approaches were utilized to investigate and describe the green-produced AgNPs. Through the use of the SEM method, it was demonstrated that the morphology of AgNPs is tetrahedral. It was determined using X-ray diffraction that the size of crystalline AgNPs was 26.7 nm. AgNPs that have been optimally synthesized have antibacterial properties that are both significant and effective against various bacterial species that have been tested at varying doses. [ABSTRACT FROM AUTHOR]

In this study, we report the synthesis of silver nanoparticles (AgNPs) from Tecoma capensis flower aqueous extract (TcAqFE). The impact of AgNPs on microstructural, optical, antibacterial and antiproliferative properties have been investigated through UV‐visible spectroscopy, X‐ray diffraction, transmission electron microscopy (TEM), fourier infra‐red spectroscopy (FTIR), agar well diffusion technique assay and MTT. The particles size estimated from TEM and XRD is in the range of 1–10 nm. The XRD pattern reveals that the Tecoma capensis silver nanoparticles (TcAgNPs) have a cubic crystal structure. FTIR spectra showed band positions at 1071, 1358, 1620, 1962, 2150, 2920 and 3361 cm−1. Surface plasmon resonance (SPR) in AgNPs became evident with an absorption peak at 407 nm. GC‐MS analysis of ethanolic flower extract revealed the presence of major phytochemical constituents, including Butanal (57.14 %), Propanol (20.23 %), Ethanone (4.88 %), Mesitylene (3.70 %), Hexanal (3.33 %), 4‐Cyclopentene‐1,3‐diol, trans (3.16 %), Furan (2.94 %), 5‐Hepten‐2‐one (2.58 %), and Acetic acid (1.68 %). The antibacterial assay results clearly indicate that the TcAgNPs exhibited the maximum activity against Salmonella typhi, with inhibition zone (IZ) values of (40±1.4 mm), followed by Bacillus subtilis (35.66±2.0 mm), Staphylococcus aureus (32.6±0.64 mm), Escherichia. coli (29.66±2.05 mm), Listeria monocytogenes (27±1.63 mm), and Klebsiella pneumoniae exhibiting the least IZ values (23±1.6 mm). Minimum inhibitory concentration (MIC) values ranged from 0.20 to 2.81 mg/mL. The highest MIC value 2.81 mg/mL was observed in case of Salmonella typhi, while Staphylococcus aureus (0.20 mg/mL), displayed the lowest MIC values. The MIC of Gentamycin also ranged from 0.012 to 0.024 mg/mL. MTT assay demonstrated that the aqueous extract was potent against the cancer cell line A549, with a GI50 of 71.79 μg/mL. These results suggest that TcAgNPs have therapeutic potential and can serve as antibacterial and antiproliferative agents to protect against several ailments. [ABSTRACT FROM AUTHOR]

Green silver nanoparticles (AgNPs) possess tremendous promise for diverse applications due to their versatile characteristics. Coriander and other plant extracts have become popular for greenly synthesizing AgNPs as an economical, biocompatible, cost-effective, and environmentally beneficial alternative to chemical processes. In this study, we synthesized AgNPs from coriander leaves and evaluated their antibacterial, anti-inflammatory, antioxidant, and wound-healing acceleration properties in comparison to chemically synthesized AgNPs. The zeta potentials of AgNPs extracted from green and chemical processes were −32.4 mV and −23.4 mV, respectively. TEM images showed a cuboidal shape of green and chemical AgNPs with a diameter of approximately 100 nm. The FTIR spectra of green AgNPs showed an extreme absorption peak at 3401 cm−1, which signifies O-H stretching vibrations, typically linked to hydroxyl groups. In vitro results elaborated that AgNPs from coriander exerted a stronger effect on anti-Klebsiella pneumoniae (KP) through interrupting cell integrity, generating ROS, depleting ATP, and exhibiting significant antioxidant activity, compared with AgNPs synthesized chemically. In vivo experiments showed that AgNPs from coriander, as opposed to chemically manufactured AgNPs, greatly accelerated the healing of wounds contaminated with Klebsiella pneumoniae bacteria by effectively eliminating the bacteria on the wounds and stimulating skin regeneration and the deposition of dense collagen. In vivo assays further demonstrated that green AgNPs effectively enhanced Klebsiella pneumoniae-infected wound healing by extenuating local inflammatory responses and up-regulating VEGF and CD31 expression. In conclusion, green AgNPs significantly alleviated the inflammation without significantly harming the organism. [ABSTRACT FROM AUTHOR]

Natural products derived from medicinal plants offer convenience and therapeutic potential and have inspired the development of antimicrobial agents. Thus, it is worth exploring the combination of nanotechnology and natural products. In this study, silver nanoparticles (AgNPs) were synthesized from the leaf extract of Ginkgo biloba (Gb), having abundant flavonoid compounds. The reaction conditions and the colloidal stability were assessed using ultraviolet–visible spectroscopy. X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy (FTIR) were used to characterize the AgNPs. AgNPs exhibited a spherical morphology, uniform dispersion, and diameter ranging from ~8 to 9 nm. The FTIR data indicated that phytoconstituents, such as polyphenols, flavonoids, and terpenoids, could potentially serve as reducing and capping agents. The antibacterial activity of the synthesized AgNPs was assessed using broth dilution and agar well diffusion assays. The results demonstrate antibacterial effects against both Gram-positive and Gram-negative strains at low AgNP concentrations. The cytotoxicity of AgNPs was examined in vitro using the CCK-8 method, which showed that low concentrations of AgNPs are noncytotoxic to normal cells and promote cell growth. In conclusion, an environmentally friendly approach for synthesizing AgNPs from Gb leaves yielded antibacterial AgNPs with minimal toxicity, holding promise for future applications in the field of biomedicine. [ABSTRACT FROM AUTHOR]

Nanoparticles are unique and show different physical and chemical properties from their bulk material. Silver nanoparticles have a variety of antimicrobial applications. In the present study Silver nanoparticles (Ag-NPs) were synthesized by green methodology using the plant Moringa oliefera Lam. leaf extract. The main objective of this study was to synthesize silver nanoparticles without using any hazardous chemicals for future biomedical uses. M. oleifera Lam. is a well-known medicinal plant and is used in the preparation of different ayurvedic medicines. This plant is a rich source of polyphenols, folic acid, and beta-carotene. The effect of temperature on the synthesis of nanoparticles was also determined. The synthesized silver nanoparticles showed an absorbance peak at 430 nm with a UV-Vis spectrophotometer. X-ray diffraction study and TEM analysis exhibited the crystalline nature of silver nanoparticles and revealed that their size is 20-30 nm. An antimicrobial activity study was also performed against the most common nosocomial pathogens and the results revealed that the synthesized Ag-NPs have significant antimicrobial properties against MRSA, Escherichia coli, Klebsiella (ESBL), and Salmonella enterica. The antibacterial efficacy of silver nanoparticles was also determined using MIC and MBC. This study concluded that M. oliefera Lam. exhibited strong potential for the synthesis of silver nanoparticles. These synthesized silver nanoparticles are stable and eco-friendly and could be used to control bacterial growth of common pathogenic microorganisms including some multi-drug resistant (MDR) bacterial strains such as MRSA and Klebsiella (ESBL). [ABSTRACT FROM AUTHOR]

Bacterial infections pose a significant threat to human health and safety, necessitating the urgent resolution of the problem through the development and implementation of highly effective antibacterial agents. However, the emergence of multidrug-resistant bacteria has diminished the satisfactory effectiveness of antibacterial treatments. To overcome this obstacle, we developed effective antibacterial agents by chemical reduction for inhibiting bacterial proliferation and inducing membrane damage. Specifically, four different types of chitosan/Ag nanoparticle (CS-AgNPs-i) (i-1, 2, 3, 4) complexes were synthesized by varying the quantity of chitosan added during the synthesis process. We found that the amount of CS does not affect the morphology and size of CS-AgNPs-i, which remained at approximately 20 nm and all CS-AgNPs were mostly spherical. The zeta potential measurements indicated that the surface of CS-AgNPs carries a positive charge. Notably, elevating the chitosan concentration led to a more pronounced antibacterial impact, particularly evident in its interaction with the peptidoglycan layer on the bacterial surface. Our experimental results undeniably establish the potent antibacterial efficacy of CS-AgNPs against both Escherichia coli and Staphylococcus aureus. Employing live/dead bacterial staining, we reveal the marked capability of CS-AgNPs to effectively hinder bacterial proliferation. Furthermore, our experimental investigations revealed that CS-AgNPs possess broad-spectrum antimicrobial activity. The results of in vitro cytotoxicity experiments substantiated the high biocompatibility of CS-AgNPs with elevated chitosan loading. The study provides valuable insights into the development of nano-antibacterial agents that exhibit significant potential as a substitute to replace traditional antibiotics for medical applications. [ABSTRACT FROM AUTHOR]

The green synthesis of silver nanoparticles (AgNPs) using the cell-free supernatant of a Haematococcus pluvialis culture (CFS) was implemented in the current study, under illumination conditions. The reduction of Ag+ to AgNPs by the CFS could be described by a pseudo-first-order kinetic equation at the temperature range tested. A high reaction rate during synthesis and stable AgNPs were obtained at 45 °C, while an alkaline pH (pH = 11.0) and a AgNO3 aqueous solution to CFS ratio of 90:10 (v/v) proved to be the most effective conditions in AgNPs synthesis. A metal precursor (AgNO3) at the concentration range tested (1–5 mM) was the limited reactant in the synthesis process. The synthesis of AgNPs was accomplished under static and agitated conditions. Continuous stirring enhanced the rate of reaction but induced aggregation at prolonged incubation times. Zeta potential and polydispersity index measurements indicated stable AgNPs and the majority of AgNPs formation occurred in the monodisperse phase. The X-ray diffraction (XRD) pattern revealed the face-centered cubic structure of the formed AgNPs, while TEM analysis revealed that the AgNPs were of a quasi-spherical shape with a size from 30 to 50 nm. The long-term stability of the AgNPs could be achieved in darkness and at 4 °C. In addition, the synthesized nanoparticles showed antibacterial activity against Escherichia coli. [ABSTRACT FROM AUTHOR]

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

Ag NPs were generated by reducing silver ions with sodium borohydride and then loaded into a zirconium-based MOF, PCN-222, resulting in a deep purple powder, PCN-222@AgNPs, which exhibited photocatalytic activity. The material was characterized and found to have Ag NPs uniformly dispersed in the pores of PCN-222, with a content of 6.0306%. PCN-222@AgNPs had rod-shaped structures of micrometer sizes with irregular spherical Ag NPs on their surfaces, as revealed by scanning electron microscopy and transmission electron microscopy. In experiments on Ag NPs release and reactive oxygen species (ROS) detection, PCN-222@AgNPs effectively released Ag NPs into an aqueous solution and promote ROS generation. Finally, the antibacterial activities of PCN-222@AgNPs against Escherichia coli and Staphylococcus aureus were assessed by in vitro experiments. Results indicated that PCN-222@AgNPs had lower minimum bactericidal concentration (MBC) compared to PCN-222 in both light and dark environments. The MBC further decreased under light conditions due to the enhanced photocatalytic performance of the composite material and the promotion of Ag NPs release by ROS. These findings demonstrate that PCN-222@AgNPs have synergistic antibacterial effects under visible light irradiation. [ABSTRACT FROM AUTHOR]

The paper presents the results of the study of the application of plasma technologies for creating materials with antimicrobial properties, namely, the application of radio-frequency (RF) plasma treatment to modify polypropylene (PP) nonwoven materials with antibacterial agents based on silver nanoparticles, modification of leather materials by cathode-ion bombardment with the formation of nitride nanostructures, the antibacterial properties of the obtained materials were studied. It has been shown that the use of RF plasma modification makes possible to obtain disposable medical materials characterized by pronounced antibacterial activity across their surface area, and leather material with condensed nitride layers has a barrier effect on ion migration and antimicrobial activity in the absence of cytotoxicity, which makes this material promising for making prosthetic elements. [ABSTRACT FROM AUTHOR]

Samples of reduced graphene oxide aerogels decorated with silver nanoparticles (from 1 to 15 wt %) have been obtained. The reduction of silver ions was performed in the course of the reduction of graphene oxide (GO) and self-assembly of the aerogel with the use of glucose as a green reducing agent. It has been found that all composite graphene aerogel samples GO–Ag have antibacterial properties. The minimum inhibitory concentrations (MICs) of the gram-negative bacteria E. coli and the gram-positive bacteria M. luteus were determined. It was found that the samples GO–Ag10 and GO–Ag15 for E. coli and the samples GO–Ag15 for M. luteus can exhibit both bacteriostatic and bactericidal effects. It was shown that all samples other than GO–Ag15 at MICs effectively inhibited the formation of biofilms of M. luteus bacteria. At the same time, the sample GO–Ag15 at a minimum bactericidal concentration, which is higher than the MIC by a factor of 9.5, effectively destroyed already formed biofilms of M. luteus bacteria. [ABSTRACT FROM AUTHOR]

This study aims to characterize and determine the antibacterial activities of synthesized Strobilanthes crispus-mediated AgNPs (SC-AgNPs) against Streptococcus mutans, Escherichia coli and Pseudomonas aeruginosa. S. crispus water extract acts as a reducing and capping agent in the synthesis of AgNPs. The synthesized AgNPs were characterized by using UV-Vis spectrophotometer, dynamic light scattering (DLS), field emission scanning electron microscope (FESEM), X-ray diffractometer (XRD) and Fourier transform infra-red (FTIR). FESEM images showed a rough surface with a spherical shape. The average size distribution of 75.25 nm with a polydispersity index (PDI) of 0.373. XRD analysis matched the facecentred cubic structure of silver. FTIR analysis revealed a shifted peak from 1404.99 to 1345.00 cm-1. MIC and MBC values of SC-AgNPs were 1.25 mg/mL and 2.5 mg/mL against E. coli, P. aeruginosa and S. mutans, respectively. Time-kill assay showed that SC-AgNPs significantly reduced bacterial growth as compared to non-treated bacteria. Morphologies of bacteria treated with SC-AgNPs were shrunk, lysed, irregular and smaller as compared to control. SC-AgNPs significantly disrupted the gene expression of eae A, gtf B and Pel A (p<0.05). This study indicated that the synthesized SC-AgNPs were stable with enhanced antibacterial activities. [ABSTRACT FROM AUTHOR]

The use of silver nanoparticles (Ag-NPs) in different fields such as agriculture, medicine, and environment has recently increased. As a result, studies on their synthesis and applications have gained attention. In the present study, the synthesis of Ag-NPs using cheap, renewable, and environmentally friendly phytochemicals extracted from Vachellia xanthophloea leaves is reported. Additionally, potential uses of the nanoparticles against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria and for sensing of mercury ions from aqueous solutions were investigated. The findings showed that the formation of nanoparticles was associated with a color change from green to brown with a UV–Vis maximal absorbance peak at 420 nm due to surface plasmon resonance on Ag-NPs. The synthesized Ag-NPs showed effective antibacterial effects against both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. The antibacterial effectiveness as indicated by the minimum inhibitory concentration (MIC) was higher for Staphylococcus aureus (0.04 mg/mL) compared to E. coli (0.33 mg/mL). Similarly, the minimum bactericidal concentration (MBC) values were 0.04 and 0.66 mg/mL for S. aureus and E. coli, respectively. The nanoparticles were also sensitive to metal ions (Hg2+, Ba2+, Mg2+, Zn2+, Cu2+, Ni2+, Co2+, and Fe2+) and showed a remarkable selectivity to mercury. The potential use of the nanoparticles for sensing of mercury ions from real water samples of ground and tap waters produced satisfactory results. The limit of detection (LOD) and limit of quantification (LQD) for sensing of Hg2+ were determined to be 22.2 µM and 73.9 µM, respectively. The findings from the current study indicate that Ag-NPs prepared using Vachellia xanthophloea leaves aqueous extract could serve as effective an antibacterial agent and a sensor of mercury ions for aqueous samples. [ABSTRACT FROM AUTHOR]

Green synthesis of silver nanoparticles (AgNPs) has attracted substantial interest and achievement due to their environmental friendliness, ease of manipulation, and potential for large-scale production. By using aqueous Camellia sinensis leaf extract, suspensions of AgNPs, which possess photocatalytic and biological activity, were successfully synthesized in this study. The reduction of silver ions to AgNPs was visually inspected via the colour of the reaction mixture, which was altered from pale yellow to reddish brown. The methods of characterization of the as-synthesized AgNPs were performed using Ultraviolet-Visible spectroscopy (UV-Vis), dynamic light scattering technique (DLS), and X-ray diffraction analysis (XRD). The surface plasmon resonance bands of AgNPs at 420-430 nm in UV-Vis spectra indicated the presence of silver particles at the nanoscale. The size of AgNPs was determined by DLS, ranging from 25 nm to 40 nm. XRD analysis showed that AgNPs were highly pure and crystalline. The antibacterial activity of AgNPs against Gram-positive and Gram-negative bacterial strains, including Staphylococcus aureus and Escherichia coli, respectively, was demonstrated by the disc diffusion method. The examination of the photocatalytic activity of AgNPs was conducted through methylene blue (MB) degrading experiments, and the MB degrading performance was approximately 95% within 72 h under sunlight. [ABSTRACT FROM AUTHOR]

The need for prehospital hemostatic dressings that exert an antibacterial effect is of interest for prolonged field care. Here, we consider a series of antibacterial and zeolite formulary treatment approaches applied to a cotton-based dressing. The design of the fabric formulations was based on the hemostatic dressing TACGauze with zeolite Y incorporated as a procoagulant with calcium and pectin to facilitate fiber adherence utilizing silver nanoparticles, and cellulose-crosslinked ascorbic acid to confer antibacterial activity. Infra-red spectra were employed to characterize the chemical modifications on the dressings. Contact angle measurements were employed to document the surface hydrophobicity of the cotton fabric which plays a role in the contact activation of the coagulation cascade. Ammonium Y zeolite-treated dressings initiated fibrin equal to the accepted standard hemorrhage control dressing and showed similar improvement with antibacterial finishes. The antibacterial activity of cotton-based technology utilizing both citrate-linked ascorbate-cellulose conjugate analogs and silver nanoparticle-embedded cotton fibers was observed against Staphylococcus aureus and Klebsiella pneumoniae at a level of 99.99 percent in the AATCC 100 assay. The hydrogen peroxide levels of the ascorbic acid-based fabrics, measured over a time period from zero up to forty-eight hours, were in line with the antibacterial activities. [ABSTRACT FROM AUTHOR]

Greenly synthesized silver nanoparticles (AgNPs) are gaining attention as potential antimicrobials. We report on the green method for the synthesis of poly (vinyl alcohol) (PVA) – silver nanoparticles (PVA‐AgNPs) composite 1 using Kendu (Diospyros melanoxylon Roxb) fruit peel (KFP) aqueous extract. The use of KFP extract for the synthesis of AgNPs in the composite has been investigated for the first time. UV−visible spectroscopy and transmission electron microscopy (TEM) are employed to characterize the prepared AgNPs. The FTIR and 1H NMR spectral analyses reveal the involvement of phytochemicals of the KFP extract in the composite synthesis. The composite exhibits strong antibacterial activity against both Gram‐ negative Escherichia coli and Gram‐positive Staphylococcus aureus bacterial pathogens and action increases with AgNPs content. [ABSTRACT FROM AUTHOR]

Much attention has been gained on green silver nanoparticles (green-AgNPs) in the medical field due to their remarkable effects against multi-drug resistant (MDR) microorganisms and targeted cancer treatment. In the current study, we demonstrated a simple and environment-friendly (i.e., green) AgNP synthesis utilizing Jacobaea maritima aqueous leaf extract. This leaf is well-known for its medicinal properties and acts as a reducing and stabilizing agent. Nanoparticle preparation with the desired size and shape was controlled by distinct parameters; for instance, temperature, extract concentration of salt, and pH. The characterization of biosynthesized AgNPs was performed by the UV-spectroscopy technique, dynamic light scattering, scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared. The successful formation of AgNPs was confirmed by a surface plasmon resonance at 422 nm using UV-visible spectroscopy and color change observation with a particle size of 37± 10 nm and a zeta potential of −10.9 ± 2.3 mV. SEM further confirmed the spherical size and shape of AgNPs with a size varying from 28 to 52 nm. Antibacterial activity of the AgNPs was confirmed against all Gram-negative and Gram-positive bacterial reference and MDR strains that were used in different inhibitory rates, and the highest effect was on the E-coli reference strain (MIC = 25 μg/mL). The anticancer study of AgNPs exhibited an IC50 of 1.37 μg/mL and 1.98 μg/mL against MCF-7 (breast cancer cells) and A549 (lung cancer cells), respectively. Therefore, this green synthesis of AgNPs could have a potential clinical application, and further in vivo study is required to assess their safety and efficacy. [ABSTRACT FROM AUTHOR]

The era of increasing bacterial antibiotic resistance requires new approaches to fight infections. With this purpose, silver-based nanomaterials are a reality in some fields and promise new developments. We report the green synthesis of silver nanoparticles (AgNPs) using culture broths from a microalga. Broths from two media, with different compositions and pHs and sampled at two growth phases, produced eight AgNP types. Nanoparticles harvested after several synthesis periods showed differences in antibacterial activity and stability. Moreover, an evaluation of the broths for several consecutive syntheses did not find relevant kinetics or activity differences until the third round. Physicochemical characteristics of the AgNPs (core and hydrodynamic sizes, Z-potential, crystallinity, and corona composition) were determined, observing differences depending on the broths used. AgNPs showed good antibacterial activity at concentrations producing no or low cytotoxicity on cultured eukaryotic cells. All the AgNPs had high levels of synergy against Escherichia coli and Staphylococcus aureus with the classic antibiotics streptomycin and kanamycin, but with ampicillin only against S. aureus and tetracycline against E. coli. Differences in the synergy levels were also dependent on the types of AgNPs. We also found that, for some AgNPs, the killing of bacteria started before the massive accumulation of ROS. [ABSTRACT FROM AUTHOR]

Application of nanotechnology for the synthesis of silver nanoparticles using plant extract can be a promising alternative to traditional chemical methods. Products of biological origin have less side effects, thus are safe for human health besides being cost-effective and pollution-free. Keeping in view this, the current work was designed for the environment-friendly production of silver nanoparticles (AgNPs) utilising Isodon coetsa acetone leaf extract. The effect of some important variables including incubation time, pH, AgNO3 concentration, temperature and volume of plant extract were examined for the optimum production of AgNPs. Synthesized nanoparticles were further characterized using atomic force microscopy (AFM), X-ray diffraction spectroscopy (XRD), and UV-visible absorption spectroscopy. In addition, the antibacterial potential of nanoparticles was also determined by agar-well diffusion method. The optimal conditions for synthesis of AgNPs achieved after 24 h of incubation at pH 9.0, 2mM AgNO3, 60°C temperature, and using 10% I. coetsa leaf extract. X-ray diffraction spectroscopy revealed that the size of the strongest peak for AgNPs was 9.5 nm, while atomic force microscopy confirmed their spherical shape with smooth surface without any pinholes or cracks. AgNPs showed excellent antibacterial action against Gram-positive and Gram-negative bacteria. The current study has contributed to the development of a simple and fast bioprocess for the synthesis of AgNPs of the appropriate size and form which also have increased antibacterial activity in comparison to crude extract. Therefore, the process of biogenically synthesised AgNPs from plants is a straightforward, commercially feasible, and environmentally benign approach that can be used in disease control while utilizing their important role as therapeutic agent for treating various ailments caused by pathogenic bacteria. [ABSTRACT FROM AUTHOR]

Antibiotic-resistant bacterial strains and the consequent surge in infections caused by them have become major public health concerns. Silver nanoparticles (AgNPs) exhibit antibacterial properties and have wide applications in biomedical sciences. In this study, AgNPs were synthesized in the presence of antibiotics: Ceftazidime (Cft), Cefotaxime (Cef), Ceftriaxone (Cfx), and Cefepime (Cpm), along with the extract of Mentha longifolia. Mentha longifolia-based AgNPs were kept as the control for all experiments. The associated metabolites, structural properties, surface charges, and antibacterial activity of the AgNPs were also evaluated. Overall, a blue-shift of SPR peaks was observed for control AgNPs (λmax = 421 nm, 422 nm, 426 nm, and 406 nm for Cft-AgNPs, Cef-AgNPs, Cfx-AgNPs, and Cpm-AgNPs, respectively), compared to the control (λmax = 438 nm). Fourier-transform infrared spectroscopy showed that antibiotic-based AgNPs had distinct peaks that corresponded to the respective antibiotics, which were not observed in the control. XRD analysis showed that there were observed changes in crystallinity in antibiotic-based AgNPs compared to the control. TEM images revealed that all samples had spherical nanoparticles with different sizes and distributions compared to the control. The Zeta potential for extract-based AgNPs was − 33.6 mV, compared to -19.6 mV for Cft-AgNPs, -2 mV for Cef-AgNPs, -21.1 mV for Cfx-AgNPs, and − 24.2 mV for Cpm-AgNPs. The increase in the PDI value for antibiotic-based AgNPs also showed a highly polydisperse distribution. However, the antibiotic-AgNPs conjugates showed significantly higher activity against pathogenic bacteria. The addition of antibiotics to AgNPs brought significant changes in structural properties and antibacterial activities. [ABSTRACT FROM AUTHOR]

The scientific society is exploiting the use of nanoparticles in nano-medicine and biomedical applications. In the field of biomaterial and bio-nanotechnology, silver nanoparticles (AgNPs) are playing an important role due to their potential physical, chemical, and biological properties ranging in activities from antibacterial, antiviral, antifungal, and anticancer treatment. Green synthesis technology is one of the most cost-effective, eco-friendly, and biologically safe methods. Green tea leaf extract can reduce silver to AgNPs and enhance antibacterial activity. In this work, we demonstrate the antibacterial activity effect employing green synthesis of AgNPs with green tea leaf extract. The UV–Vis and FTIR results showed, confirming the formation of AgNPs and the presence of chemical groups enhancing the antibacterial activity of AgNPs. The synthesized AgNPs with green tea leaf extract were crystalline with a quasi-spherical shape with a diameter from 30 to 150 nm. The antibacterial activity of the AgNPs in three different concentrations showed that the 120 mg/ml sample possesses higher antibacterial activity (significantly high killing ability) against E. coli than chemically produced AgNPs. These results confirm a more significant antibacterial effect of the biogenic AgNPs with low cytotoxicity than the AgNPs produced chemically. These findings can be used to treat chronic infections, diseases, and other biomedical applications. [ABSTRACT FROM AUTHOR]

The green production of silver nanoparticles (AgNPs) produces AgNPs with minimum influence on the environment by using plant components such as alkaloids, carbohydrates, lipids, enzymes, flavonoids, terpenoids, and polyphenols as reducing agents. In the present investigation, Azadirachta indica leaf extract was used to form AgNPs from a 1 mM silver nitrate solution. The plan proved to be incredibly straightforward, cost‐effective, and effective. The production of the nanoparticles was observed visually, where the colorless fluid turns into a brown‐colored solution. Further research was carried out using x‐ray diffraction, Fourier‐transform infrared analysis, scanning electron microscopy, and transmission electron microscopy (TEM) in addition to UV–visible spectroscopy. The size range of AgNPs determined by TEM was 10–30 nm. When the diffusion technique was employed to demonstrate the antibacterial effect of AgNPs on various pathogens, the zones of inhibition for Staphylococcus aureus, Bacillus cereus, and Escherichia coli, when 50 g of AgNPs were used were 16, 12, and 17 mm, respectively. By examining the leakage of reducing sugars and proteins, the mechanism by which nanoparticle antibacterial properties were explored, showed that AgNPs were capable of lowering membrane permeability. [ABSTRACT FROM AUTHOR]

Nanotechnology has emerged as a promising field for the development of novel antibacterial agents with reduced environmental impact. In this study, we present a novel green synthesis approach for the production of silver nanoparticles (AgNPs) using a plant-based extract. These AgNPs were subsequently characterized using various analytical techniques, including UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FTIR). UV-Vis spectroscopy confirmed the formation of AgNPs by exhibiting a characteristic surface plasmon resonance peak at around 401 and 420 nm. XRD analysis revealed the crystalline nature of the AgNPs, with distinct diffraction peaks corresponding to the face-centered cubic structure of silver. TEM analysis demonstrated that the synthesized AgNPs were predominantly spherical in shape and exhibited an average size within the nanoscale range. FTIR analysis was employed to elucidate the potential bioactive compounds present in the plant extract responsible for the reduction and stabilization of AgNPs. Furthermore, we evaluated the antibacterial activity of these synthesized AgNPs against a panel of bacterial isolates. All the bacterial isolates were sensitive to the silver nanoparticles. Staphylococcus aureus as found to be most resistant, while E. coli as found to be the most sensitive. [ABSTRACT FROM AUTHOR]

The use of plant extracts to produce metal particles at the nanoscale has attracted intensive research interest due to their cost-effectiveness and eco-friendliness. This study aimed to investigate the synthesis of silver nanoparticles (AgNPs(using aqueous extracts of Silybum marianum L. and Portulaca oleracea L. and to assess their effectiveness as antibacterial and antifungal agents using the agar-well diffusion method. The production of AgNPs was confirmed through spectrophotometry, and their size and shape were measured using Transmission Electron Microscopy (TEM). The role of organic compounds in nanoparticle synthesis was also explored through Fourier Transform Infrared Spectroscopy (FTIR). The FTIR analysis identified the functional groups of organic compounds in S. marianum and P. oleracea extracts that were responsible for reducing Ag ions and capping the resulting AgNPs. The nanoparticles demonstrated potent antimicrobial properties against Escherichia coli, Staphylococcus aureus, Fusarium graminearum, and Alternaria alternata. It was concluded that, in addition to their unique medicinal properties, S. marianum and P. oleracea can be utilized in the production of AgNP for medical and pharmaceutical purposes against Gram-positive and Gram-negative bacteria, as well as fungal infections. In summary, the seed extracts of S. marianum and P. oleracea, which are among the available plant sources, can be used for the highly stable production of AgNPs as a reducing and capping agent. [ABSTRACT FROM AUTHOR]

Silver nanoparticles have special plasmonic and antibacterial characteristics that make them efficient in a variety of commercial medical applications. According to recent research, chemically synthesized silver nanoparticles are harmful even in low concentrations. It was crucial to identify appropriate synthesis methods that may have low costs and be nontoxic to the environment. Zingiber officinale (ginger) extracts used to prepare silver nanoparticles were inexpensive and environmentally friendly, and the best physicochemical characteristics were analyzed. Silver nanoparticles were characterized by using UV-visible spectroscopy, Scanning electron microscopy (SEM), and X-ray diffraction (XRD). The surface Plasmon resonance peak at 425 nm was observed using UV-Visible spectroscopy. Scanning electron microscopy observed that the nanoparticles were spherical and ranged in size from 5 to 35 nm. The XRD pattern values of 2θ: 38.2o, 46.3o, and 64.58o are used to determine the planes (111), (200), and (220). The silver nanoparticle's existence was verified by the face-centered cubic (FCC). Silver nanoparticles were found to have antibacterial efficacy against gram-positive Staphylococcus and gram-negative bacteria such as Pseudomonas aeruginosa, Klebsiella Aerogenes, Salmonella, Staphylococcus and Escherichia coli. The antibacterial activity of silver nanoparticles was observed using the agar well diffusion (AWD) method at three different concentrations (100 μg/ml, 75 μg/ml, and 50 μg/ml). The zone of inhibition measured against the bacterial strains pseudomonas Aeruginosa, Klebsiella aerogenes, Escherichia coli, Salmonella and Staphylococcus which were (18.4±1.25 mm, 16.9±0.74 mm, 14.8±1.25 mm), (16.8±0.96 mm, 14.6±0.76 mm, 14.0±1.15 mm), (19.7±0.76 mm, 18.2±0.66 mm, 15.4±1.15 mm), (16.6±0.67 mm, 14.2±0.23 mm, 12.8±0.78 mm) and (12±0.68 mm, 10±0.20 mm, 08±0.15 mm). These nanoparticles' potent antibacterial properties may enable them to be employed as nanomedicines for a variety of gram-negative bacterial illness treatments. [ABSTRACT FROM AUTHOR]

Antibiotic nanocomposite polymers show great promise in treating a variety of pathogens that cause widespread disease. Sodium alginate-grafted diphenylamine (NaAlg-g-DPA) embedded with different ratios of silver nanoparticles (AgNPs) was fabricated and characterized through different techniques including FTIR, XRD, and SEM techniques for investigating the antimicrobial activity. XRD confirmed the crystallinity of these compounds, and the average crystal size of Na Alg-g-DPA/Ag was estimated to be 48.6 nm. Then it was applied as an antimicrobial agent and evaluated through two ways (inhibition zone and MIC techniques) against Staphylococcus aureus as gram-positive bacteria with an inhibition zone of 19.31.6 mm and 18.60.63 mm against Escherichia coli as gram-negative bacteria while with increasing the Ag ratio 2:1 there was an enhancement in their biological activity to be 21.90.69 mm against Staphylococcus aureus and with an inhibition zone of 21.32.1 mm against Escherichia coli. The outcomes of this investigation are important for the development of new composite materials with antibacterial properties for industrial applications. [ABSTRACT FROM AUTHOR]

Bacterial pathogens cause pain and death, add significantly to the expense of healthcare globally, and pose a serious concern in many aspects of daily life. Additionally, they raise significant issues in other industries, including pharmaceuticals, clothing, and food packaging. Due to their unique properties, a great deal of attention has been given to biogenic metal nanoparticles, nanocomposites, and their applications against pathogenic bacteria. This study is focused on biogenic silver and copper nanoparticles and their composites (UL/Ag2 O-NPS, Ul/CuO-NPs, and Ul/Ag/Cu-NCMs) produced by the marine green alga Ulva lactuca. The characterization of biogenic nanoparticles UL/Ag2 O-NPS and Ul/CuO-NPs and their composites Ul/Ag/Cu-NCMs has been accomplished by FT-IR, SEM, TEM, EDS, XRD, and the zeta potential. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) experiments were conducted to prove antibacterial activity against both Gram-positive and Gram-negative bacteria and anti-biofilm. The FTIR spectroscopy results indicate the exiting band at 1633 cm−1, which represents N–H stretching in nanocomposites, with a small shift in both copper and silver nanoparticles, which is responsible for the bio-reduction of nanoparticles. The TEM image reveals that the Ul/Ag/Cu-NCMs were hexagonal, and the size distribution ranged from 10 to 35 nm. Meanwhile, Ul/CuO-NPs are rod-shaped, whereas UL/Ag2 O-NPS are spherical. The EDX analysis shows that Cu metal was present in a high weight percentage over Ag in the case of bio-Ag/Cu-NCMs. The X-ray diffraction denotes that Ul/Ag/Cu-NCMs, UL/CuO-NPs, and UL/Ag2 O-NPS were crystalline. The results predicted by the zeta potential demonstrate that Ul/Ag/Cu-NCMs were more stable than Ul/CuO-NPs. The antibacterial activity of UL/Ag2 O-NPS, Ul/Ag/Cu-NCMs, and UL/CuO-NPs was studied against eleven Gram-negative and Gram-positive multidrug-resistant bacterial species. The maximum inhibition zones were obtained with UL/Ag2 O-NPS, followed by Ul/Ag/Cu-NCMs and Ul/CuO-NPs in all the tested bacteria. The maximum anti-biofilm percentage formed by E. coli KY856933 was obtained with UL/Ag2 O-NPS. These findings suggest that the synthesized nanoparticles might be a great alternative for use as an antibacterial agent against different multidrug-resistant bacterial strains. [ABSTRACT FROM AUTHOR]

In this study, we developed highly efficient nonwoven membranes by modifying the surface of polypropylene (PP) and poly(butylene terephthalate) (PBT) through photo-grafting polymerization. The nonwoven membrane surfaces of PP and PBT were grafted with poly(ethylene glycol) diacrylate (PEGDA) in the presence of benzophenone (BP) and metal salt. We immobilized tertiary amine groups as BP synergists on commercial nonwoven membranes to improve PP and PBT surfaces. In situ Ag, Au, and Au/Ag nanoparticle formation enhances the nonwoven membrane surface. SEM, FTIR, and EDX were used to analyze the surface. We evaluated modified nonwoven membranes for photocatalytic activity by degrading methylene blue (MB) under LED and sunlight. Additionally, we also tested modified membranes for antibacterial activity against E. coli. The results indicated that the modified membranes exhibited superior efficiency in removing MB from water. The PBT showed the highest efficiency in dye removal, and bimetallic nanoparticles were more effective than monometallic. Modified membranes exposed to sunlight had higher efficiency than those exposed to LED light, with the PBT/Au/Ag membrane showing the highest dye removal at 97% within 90 min. The modified membranes showed reuse potential, with dye removal efficiency decreasing from 97% in the first cycle to 85% in the fifth cycle. [ABSTRACT FROM AUTHOR]

In this work, we report a two-step methodology for the synthesis of small silver nanoparticles embedded into hydrogels based on chitosan (CS) and hydroxypropyl methylcellulose (HPMC) biopolymers. This method uses d-glucose as an external green reducing agent and purified water as a solvent, leading to an eco-friendly, cost-effective, and biocompatible process for the synthesis of silver nanocomposite hydrogels. Their characterization comprises ultraviolet-visible spectroscopy, Fourier-transform infrared spectra, differential scanning calorimetry, scanning electron microscopy with energy-dispersive spectroscopy, and transmission electron microscopy assays. Moreover, the structural stability of the hydrogels was investigated through sequential swelling–deswelling cycles. The nanomaterials showed good mechanical properties in terms of their structural stability and revealed prominent antibacterial properties due to the reduced-size particles that promote their use as new advanced antimicrobial agents, an advantage compared to conventional particles in aqueous suspension that lose stability and effectiveness. Finally, theoretical analyses provided insights into the possible interactions, charge transfer, and stabilization process of nanoclusters mediated by the high-electron-density groups belonging to CS and HPMC, revealing their unique structural properties in the preparation of nano-scaled materials. [ABSTRACT FROM AUTHOR]

Alternative antibacterial options and nanotechnology have gained attention as a solution to the current antibiotic resistance crisis. The use of microorganisms to synthesize nanoparticles is applauded as a sustainable alternative for the production of metal-based nanoparticles. This research screened Bacillus thuringiensis (Bt) isolated from soils collected from different sites (farmland, cattle rangeland and metal recycling dumpsite) for their silver nanoparticles (AgNPs) synthesis potential, characterised the AgNPs and assessed their antibacterial activity against selected drug-resistant bacteria. The Bt index of the sampled sites ranged from 0.1 (farmland) to 0.5 (cattle rangeland). Out of six confirmed Bt isolates; MRS21 and CR23 were selected for their AgNP synthesis potential based on their absorbance of AgNPs at 420 nm. Both isolates produced AgNPs which were anistropic and irregular in shape. The surface plasmon resonance of silver occurred at 434.5 and 440 nm with distinct FT-IR peaks at 3379 and 1643 cm− 1. Apart from the multidrug-resistant E. coli (strain 1), the AgNPs from the two selected isolates exhibited antibacterial activity against E. coli (strain 2), S. aureus and K. pneumoniae. Antibacterial activity of the AgNPs was achieved at 25 µg/mL with MIC of 25–50 µg/mL and MBC of 75–100 µg/mL. Further studies are required to assess the effect of environmental factors on the properties of AgNPs synthesized, their mechanism of antibacterial activity and, synergistic effect of AgNP and antibiotics. [ABSTRACT FROM AUTHOR]