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Search Results (281)

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Keywords = silver colloids

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16 pages, 2045 KiB  
Article
The Antimicrobial Activity of Silver Nanoparticles Biosynthesized Using Cymbopogon citratus Against Multidrug-Resistant Bacteria Isolated from an Intensive Care Unit
by Bianca Picinin Gusso, Aline Rosa Almeida, Michael Ramos Nunes, Daniela Becker, Dachamir Hotza, Cleonice Gonçalves da Rosa, Vanessa Valgas dos Santos and Bruna Fernanda da Silva
Pharmaceuticals 2025, 18(8), 1120; https://doi.org/10.3390/ph18081120 - 27 Jul 2025
Viewed by 277
Abstract
Objective: This study aimed to evaluate the in vitro efficacy of silver nanoparticles (AgNPs) synthesized by bioreduction using lemongrass (Cymbopogon citratus) essential oil against multidrug-resistant (MDR) bacteria isolated from an Intensive Care Unit (ICU). Methods: The essential oil was extracted and [...] Read more.
Objective: This study aimed to evaluate the in vitro efficacy of silver nanoparticles (AgNPs) synthesized by bioreduction using lemongrass (Cymbopogon citratus) essential oil against multidrug-resistant (MDR) bacteria isolated from an Intensive Care Unit (ICU). Methods: The essential oil was extracted and characterized by gas chromatography–mass spectrometry (GC-MS). Antioxidant activity was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, the 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, and total phenolic content. AgNPs (3 mM and 6 mM silver nitrate) were characterized by UV-Vis spectroscopy, dynamic light scattering (DLS), zeta potential, transmission electron microscopy (TEM), and Fourier-transform infrared (FTIR) spectroscopy. Bacterial isolates were obtained from ICU surfaces and personal protective equipment (PPE). Results: The essential oil presented citral A, citral B, and β-myrcene as major components (97.5% of identified compounds). AgNPs at 3 mM showed smaller size (87 nm), lower Polydispersity Index (0.14), and higher colloidal stability (−23 mV). The 6 mM formulation (147 nm; PDI 0.91; −10 mV) was more effective against a strain of Enterococcus spp. resistant to all antibiotics tested. FTIR analysis indicated the presence of O–H, C=O, and C–O groups involved in nanoparticle stabilization. Discussion: The higher antimicrobial efficacy of the 6 mM formulation was attributed to the greater availability of active AgNPs. Conclusions: The green synthesis of AgNPs using C. citratus essential oil proved effective against MDR bacteria and represents a sustainable and promising alternative for microbiological control in healthcare environments. Full article
(This article belongs to the Special Issue Therapeutic Potential of Silver Nanoparticles (AgNPs), 2nd Edition)
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18 pages, 4008 KiB  
Article
Carboxymethyl Chitosan Cinnamaldehyde Coated SilverNanocomposites for Antifungal Seed Priming in Wheat: A Dual-Action Approach Toward Sustainable Crop Protection
by María Mondéjar-López, María Paz García-Simarro, Lourdes Gómez-Gómez, Oussama Ahrazem and Enrique Niza
Polymers 2025, 17(15), 2031; https://doi.org/10.3390/polym17152031 - 25 Jul 2025
Viewed by 201
Abstract
Biogenic silver nanoparticles (AgNPs) were synthesized via a green chemistry strategy using wheat extract and subsequently functionalized with a carboxymethyl chitosan–cinnamaldehyde (CMC=CIN) conjugate through covalent imine bonding. The resulting nanohybrid (AgNP–CMC=CIN) was extensively characterized to confirm successful biofunctionalization: UV–Vis spectroscopy revealed characteristic cinnamaldehyde [...] Read more.
Biogenic silver nanoparticles (AgNPs) were synthesized via a green chemistry strategy using wheat extract and subsequently functionalized with a carboxymethyl chitosan–cinnamaldehyde (CMC=CIN) conjugate through covalent imine bonding. The resulting nanohybrid (AgNP–CMC=CIN) was extensively characterized to confirm successful biofunctionalization: UV–Vis spectroscopy revealed characteristic cinnamaldehyde absorption peaks; ATR-FTIR spectra confirmed polymer–terpene bonding; and TEM analysis evidenced uniform nanoparticle morphology. Dynamic light scattering (DLS) measurements indicated an increase in hydrodynamic size upon coating (from 59.46 ± 12.63 nm to 110.17 ± 4.74 nm), while maintaining low polydispersity (PDI: 0.29 to 0.27) and stable surface charge (zeta potential ~ −30 mV), suggesting colloidal stability and homogeneous polymer encapsulation. Antifungal activity was evaluated against Fusarium oxysporum, Penicillium citrinum, Aspergillus niger, and Aspergillus brasiliensis. The minimum inhibitory concentration (MIC) against F. oxysporum was significantly reduced to 83 μg/mL with AgNP–CMC=CIN, compared to 708 μg/mL for uncoated AgNPs, and was comparable to the reference fungicide tebuconazole (52 μg/mL). Seed priming with AgNP–CMC=CIN led to improved germination (85%) and markedly reduced fungal colonization, while maintaining a favorable phytotoxicity profile. These findings highlight the potential of polysaccharide-terpene-functionalized biogenic AgNPs as a sustainable alternative to conventional fungicides, supporting their application in precision agriculture and integrated crop protection strategies. Full article
(This article belongs to the Special Issue Polymer Materials for Environmental Applications)
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13 pages, 2748 KiB  
Article
Experimental Study of the Combined Use of Silver Nanoparticles and Graphene Oxide to Predict the Operational Properties of New Bactericidal Composite Materials
by Svetlana E. Dimitrieva, Andrey N. Timonin, Sergey A. Baskakov, Oksana A. Kuznetsova and Alexey V. Shkirin
J. Compos. Sci. 2025, 9(7), 315; https://doi.org/10.3390/jcs9070315 - 20 Jun 2025
Viewed by 341
Abstract
The aim of combining agents with different antibacterial mechanisms of action is to achieve a combined effect, which could be either the sum of their individual effects or a synergistic effect greater than the sum of these individual contributions. Mathematically, it seems reasonable [...] Read more.
The aim of combining agents with different antibacterial mechanisms of action is to achieve a combined effect, which could be either the sum of their individual effects or a synergistic effect greater than the sum of these individual contributions. Mathematically, it seems reasonable to use the simple addition of agent efficacy coefficients to simplify calculations. However, this article examines the validity of this simplification in mathematical models by calculating individual and synergistic bactericidal effects using the “black box” model. All agents were characterized according to current laboratory practice. The relative antibacterial efficacy coefficients of silver nanoparticles in a colloid with chitosan succinate (nAg SCC HTZ) and graphene oxide nanoparticles (GO) were determined. In particular, the activity of silver colloid was found to be 0.29 times the bactericidal activity of erythromycin, while the activity of GO was 0.107 times the bactericidal activity of the same antibiotic against Pseudomonas aeruginosa. At the same time, all the agents demonstrated stable bacteriostatic activity and were well described by linear regression. Testing the combined effects of agents did not reveal any drug synergy. Thus, the effect of silver at a given dose, followed by the addition of GO at a bacteriostatic dose, yielded an unreliable response, different from that of the “silver–GO” system at the same simultaneous inhibition doses (p > 0.1). The data obtained can be used to develop novel combined composite materials with bactericidal properties and to predict their characteristics. Full article
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28 pages, 14082 KiB  
Article
Eco-Friendly Synthesis of Silver Nanoparticles with Significant Antimicrobial Activity for Sustainable Applications
by Ramona Plesnicute, Cristina Rimbu, Lăcrămioara Oprica, Daniel Herea, Iuliana Motrescu, Delia Luca, Dorina Creanga and Marius-Nicusor Grigore
Sustainability 2025, 17(12), 5321; https://doi.org/10.3390/su17125321 - 9 Jun 2025
Viewed by 780
Abstract
Silver nanoparticles, with various uses in pharmacy, cosmetics, sanitation, textiles, optoelectronics, photovoltaics, etc., that are provided by worldwide industrial production, estimated to hundreds of tons annually, are finally released in the environment impacting randomly the biosphere. An alternative synthesis approach could be implemented [...] Read more.
Silver nanoparticles, with various uses in pharmacy, cosmetics, sanitation, textiles, optoelectronics, photovoltaics, etc., that are provided by worldwide industrial production, estimated to hundreds of tons annually, are finally released in the environment impacting randomly the biosphere. An alternative synthesis approach could be implemented by replacing chemical reductants of silver with natural antioxidants ensuring production and utilization sustainability with focus on environmental pollution diminishing. We synthesized silver nanoparticles by using plant extracts, aiming to offer antimicrobial products with reduced impact on the environment through sustainable green-chemistry. Fresh extracts of lemon pulp, blueberry and blackberry fruits as well as of green tea dry leaves were the sources of the natural antioxidants able to ensure ionic silver reduction and silver nanoparticle formation in the form of colloidal suspensions. The four samples were characterized by UV–Vis spectrophotometry, scanning electron microscopy, dark field optical microscopy, X-ray diffractometry, dynamic light scattering, which evidenced specific fine granularity, plasmonic features, standard crystallinity, and good stability in water suspension. Antimicrobial activity was assayed using the agar diffusion method and the bacteria kill-time technique against Staphylococcus aureus and Escherichia coli. In both cases, all silver nanoparticles revealed their adequacy for the aimed purposes, the sample synthesized with green tea showing the best efficiency, which is in concordance with its highest contents of polyphenols, flavones and best total antioxidant activity. Various applications could be safely designed based on such silver nanoparticles for sustainable chemistry development. Full article
(This article belongs to the Special Issue Recycling Materials for the Circular Economy—2nd Edition)
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23 pages, 2553 KiB  
Article
A Green Integrated Approach to Multifunctional Silver Nanoparticles Derived from Aronia melanocarpa
by Andreia Corciova, Cornelia Mircea, Adrian Fifere, Ioana-Andreea Turin Moleavin, Ana Flavia Burlec, Bianca Ivanescu, Ana-Maria Vlase, Monica Hancianu and Irina Macovei
Pharmaceutics 2025, 17(5), 669; https://doi.org/10.3390/pharmaceutics17050669 - 20 May 2025
Viewed by 614
Abstract
Background/Objectives: This study reports the green synthesis, optimization, characterization, and multifunctional evaluation of silver nanoparticles (AgNPs) using an ethanolic Aronia melanocarpa berry extract. The objective was to establish optimal synthesis conditions; assess the in vitro stability; and evaluate the antioxidant, photocatalytic, and photoprotective [...] Read more.
Background/Objectives: This study reports the green synthesis, optimization, characterization, and multifunctional evaluation of silver nanoparticles (AgNPs) using an ethanolic Aronia melanocarpa berry extract. The objective was to establish optimal synthesis conditions; assess the in vitro stability; and evaluate the antioxidant, photocatalytic, and photoprotective activities. Methods: The cytogenotoxic effects of the AgNPs were evaluated on Triticum aestivum roots. The AgNPs were synthesized via bioreduction using an ethanolic extract of A. melanocarpa under varied pH, AgNO3 concentration, extract/AgNO3 ratio, temperature, and stirring time, with optimization guided by UV–Vis spectral analysis. The AgNPs were further characterized by FTIR, DLS, TEM, and EDX. In vitro stability was evaluated over six months in different dispersion media (ultrapure water; 5% NaCl; and PBS at pH 6, 7, and 8). Biological assessments included antioxidant assays (lipoxygenase inhibition, DPPH radical scavenging, metal chelation, and hydroxyl radical scavenging), photocatalytic dye degradation, and SPF determination. Results: Optimal synthesis was achieved at pH 8, 3 mM AgNO3, extract/AgNO3 ratio of 1:9, 40 °C, and 240 min stirring. The AgNPs were spherical (TEM), well dispersed (PDI = 0.32), and highly stable (zeta potential = −40.71 mV). PBS pH 6 and 7 ensured the best long-term colloidal stability. The AgNPs displayed strong dose-dependent antioxidant activity, with superior lipoxygenase inhibition (EC50 = 18.29 µg/mL) and the effective photocatalytic degradation of dyes under sunlight. Photoprotective properties were confirmed through UV absorption analysis. The AgNPs showed a strong antimitotic effect on wheat root cells. Conclusions: The study demonstrates that A. melanocarpa-mediated AgNPs are stable, biologically active, and suitable for potential biomedical, cosmetic, and environmental applications, reinforcing the relevance of plant-based nanotechnology. Full article
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14 pages, 6056 KiB  
Article
Preparation of Colloidal Silver Triangular Nanoplates and Their Application in SERS Detection of Trace Levels of Antibiotic Enrofloxacin
by Cao Tuan Anh, Dao Tran Cao and Luong Truc-Quynh Ngan
Colloids Interfaces 2025, 9(3), 31; https://doi.org/10.3390/colloids9030031 - 16 May 2025
Viewed by 565
Abstract
Surface-enhanced Raman scattering (SERS) is a powerful technique for detecting trace amounts of chemicals due to its capacity to significantly amplify the Raman signal of the molecules of these substances. This is particularly relevant in food systems where monitoring antibiotic residues is critical [...] Read more.
Surface-enhanced Raman scattering (SERS) is a powerful technique for detecting trace amounts of chemicals due to its capacity to significantly amplify the Raman signal of the molecules of these substances. This is particularly relevant in food systems where monitoring antibiotic residues is critical for food safety. Traditional SERS substrates typically utilize colloidal silver nanospheres (AgNSs), but anisotropic silver nanoparticles with numerous sharp tips can further enhance SERS sensitivity, enabling lower detection limits suitable for food safety regulations. In this study, we describe a straightforward synthesis of colloidal silver triangular nanoplates (AgTNPls), featuring multiple sharp tips, using only four common reagents: silver nitrate, trisodium citrate, sodium borohydride (NaBH4) and hydrogen peroxide (H2O2), all at room temperature. By carefully controlling the sequence of reagent addition, specifically introducing H2O2 after NaBH4, we achieved a two-step synthesis. In the first step, AgNSs seeds form, and in the second, these seeds convert into AgTNPls, resulting in a colloid of relatively uniform AgTNPls with an edge length of approximately 52 nm. The resulting AgTNPls colloid, combined with an aluminum foil, produced an SERS substrate with high enhancement factor of 3.2 × 109 (using rhodamine 6G as a test molecule). Applied to enrofloxacin (an antibiotic widely used in livestock and aquaculture) detection, this substrate achieved a detection limit as low as 0.39 µg/L (0.39 ppb), with enrofloxacin detectable at concentrations down to 5 µg/L. This highly sensitive SERS substrate holds great promise for rapid, accurate detection of antibiotic residues in food products, aiding regulatory compliance and food safety assurance. Full article
(This article belongs to the Special Issue Food Colloids: 3rd Edition)
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16 pages, 4866 KiB  
Article
Centrifugation-Induced Stable Colloidal Silver Nanoparticle Aggregates for Reproducible Surface-Enhanced Raman Scattering Detection
by Tianyu Zhou and Zhiyang Zhang
Biosensors 2025, 15(5), 298; https://doi.org/10.3390/bios15050298 - 8 May 2025
Cited by 1 | Viewed by 721
Abstract
Colloidal noble metal nanoparticle aggregates have demonstrated significant advantages in surface-enhanced Raman scattering (SERS) analysis, particularly for online detection, due to their excellent optical properties, spatial homogeneity, and fluidic compatibility. However, conventional chemically induced aggregation methods (such as salt-induced nanoparticle aggregation) suffer from [...] Read more.
Colloidal noble metal nanoparticle aggregates have demonstrated significant advantages in surface-enhanced Raman scattering (SERS) analysis, particularly for online detection, due to their excellent optical properties, spatial homogeneity, and fluidic compatibility. However, conventional chemically induced aggregation methods (such as salt-induced nanoparticle aggregation) suffer from uncontrolled aggregation, limited stability, and narrow detection windows, which restrict their quantitative and long-term applications. In this study, we developed a non-chemical method for fabricating stable colloidal aggregates from uniform β-cyclodextrin-stabilized silver nanoparticles (β-CD@AgNPs) via centrifugation. By precisely controlling the addition rate of silver nitrate, we synthesized β-cyclodextrin-stabilized silver nanoparticles with a uniform size. Surprisingly, these nanoparticles can form highly dispersed and homogeneous colloidal aggregates simply via centrifugation, which is completely different from the behavior of traditional ligand-modified nanoparticles. Notably, the resulting aggregates exhibit excellent SERS enhancement, enabling the sensitive detection of various dyes at nanomolar levels. Furthermore, they maintain a stable SERS signal (RSD = 6.99%) over a detection window exceeding 1 h, markedly improving signal stability and reproducibility compared with salt-induced aggregates. Additionally, using pyocyanin as a model analyte, we evaluated the quantitative performance of these aggregates (LOD = 0.2 nM), achieving satisfactory recovery (82–117%) in spiked samples of drinking water, lake water, and tap water. This study provides a facile strategy for fabricating stable colloidal SERS substrates and paves the way for the advancement of SERS applications in analytical sciences. Full article
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18 pages, 1673 KiB  
Review
Silver Nanoparticles and Antibiotics: A Promising Synergistic Approach to Multidrug-Resistant Infections
by Eudald Casals, Muriel F. Gusta, Neus Bastus, Jordi Rello and Victor Puntes
Microorganisms 2025, 13(4), 952; https://doi.org/10.3390/microorganisms13040952 - 21 Apr 2025
Cited by 2 | Viewed by 2041
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Section Antimicrobial Agents and Resistance)
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9 pages, 1118 KiB  
Proceeding Paper
Color Stability of PET-G in Clear Aligners: Impact of Prolonged Exposure to Everyday Substances and Its Psychological and Social Implications
by Fabiana Nicita, Joseph Lipari, Frank Lipari and Arianna Nicita
Eng. Proc. 2025, 87(1), 50; https://doi.org/10.3390/engproc2025087050 - 21 Apr 2025
Viewed by 447
Abstract
The aesthetics of clear aligners is a critical factor that can influence patient satisfaction and psychological and social well-being. However, their transparency can be compromised by exposure to staining agents. This study aimed to evaluate the color stability of PET-G aligners following prolonged [...] Read more.
The aesthetics of clear aligners is a critical factor that can influence patient satisfaction and psychological and social well-being. However, their transparency can be compromised by exposure to staining agents. This study aimed to evaluate the color stability of PET-G aligners following prolonged exposure to common daily substances, including food, tobacco products, and cleaning agents. Flat samples of PET-G (n = 220) were immersed in various solutions, including coffee, tea, Coca-Cola, red wine, a colloidal silver-based disinfectant, nicotine, artificial saliva, cigarette smoke, and mixtures of saliva with smooth, coffee, and nicotine. Immersion times of 10 (n = 110) and 15 days (n = 110) were randomly assigned. Colorimetric assessments were conducted by measuring L*a*b* parameters before and after immersion, and total color change (ΔE) was calculated. Non-parametric statistical tests revealed significant color changes in PET-G samples after both immersion durations, with pairwise comparisons indicating notable differences in ΔE values among groups exposed to different substances, particularly coffee, tea, and Coca-Cola. The findings highlight the psychological and social impact of aligner staining on patient confidence and compliance. Understanding these effects highlights the need for enhanced patient education to improve aligner aesthetics and satisfaction. Full article
(This article belongs to the Proceedings of The 5th International Electronic Conference on Applied Sciences)
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13 pages, 4270 KiB  
Article
Fabricating a Three-Dimensional Surface-Enhanced Raman Scattering Substrate Using Hydrogel-Loaded Freeze-Induced Silver Nanoparticle Aggregates for the Highly Sensitive Detection of Organic Pollutants in Seawater
by Hai Liu, Yufeng Hu and Zhiyang Zhang
Sensors 2025, 25(8), 2575; https://doi.org/10.3390/s25082575 - 18 Apr 2025
Cited by 2 | Viewed by 550
Abstract
Surface-enhanced Raman scattering (SERS) spectroscopy faces challenges in achieving both high sensitivity and reproducibility for the detection of real samples, particularly in high-salinity matrices. In this study, we developed a high-performance, salt-resistant three-dimensional (3D) SERS substrate by integrating physically induced colloidal silver nanoparticle [...] Read more.
Surface-enhanced Raman scattering (SERS) spectroscopy faces challenges in achieving both high sensitivity and reproducibility for the detection of real samples, particularly in high-salinity matrices. In this study, we developed a high-performance, salt-resistant three-dimensional (3D) SERS substrate by integrating physically induced colloidal silver nanoparticle aggregates (AgNAs) with an agarose hydrogel. AgNAs were prepared using a freeze–thaw–ultrasonication method to minimize interference in SERS signals while significantly enhancing the detection efficiency of trace pollutants. The incorporation of the agarose hydrogel not only improved the substrate’s pollutant enrichment capability, but also effectively prevented the aggregation and sedimentation of AgNAs in salt solutions. The developed SERS substrate exhibited an ultralow detection limit of 10−12 M for Nile Blue (NB), with a 100-fold increase in sensitivity compared to colloidal AgNAs and drop-cast AgNAs solid substrates. The analytical enhancement factor (AEF) for malachite green (MG) achieved a value of 1.4 × 107. Furthermore, the substrate demonstrated excellent signal uniformity, with a relative standard deviation (RSD) of 6.74% within a 200 μm × 200 μm detection area and also show a satisfactory RSD of only 9.38% within a larger area of 1 mm × 1 mm. Notably, the 3D SERS substrate exhibited excellent stability under high-salinity conditions (0.5 M NaCl) and successfully detected a model pollutant (MG) in real seawater samples using the standard addition method. This study provides a novel strategy for highly sensitive SERS detection of trace pollutants in saline environments, offering promising applications in environmental monitoring and marine pollution analysis. Full article
(This article belongs to the Special Issue Optical Nanosensors for Environmental and Biomedical Monitoring)
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16 pages, 4473 KiB  
Article
Topical Administration of Vitamin D2 Combined with Colloidal Silver Nanoparticles Promotes Wound Repair and Protection Against Skin Irritation and UVB Irradiation in 3D Reconstructed Human Skin Models
by Francesca Truzzi, Camilla Tibaldi, Silvia Dilloo, Annalisa Saltari, Mitchell P. Levesque, Fabio Arcangeli, Alfredo Garzi, Giuseppe Ruggiero and Giovanni Dinelli
Pharmaceutics 2025, 17(4), 472; https://doi.org/10.3390/pharmaceutics17040472 - 4 Apr 2025
Viewed by 668
Abstract
Background/Objectives: There is a great demand for novel, multipurpose, natural skin-care products in the global skin repair and sun protection markets. Within this framework, the potential benefits of topical Vitamin D2 (VD2) administration in combination with silver nanoparticles (AgNPs) were examined. Methods [...] Read more.
Background/Objectives: There is a great demand for novel, multipurpose, natural skin-care products in the global skin repair and sun protection markets. Within this framework, the potential benefits of topical Vitamin D2 (VD2) administration in combination with silver nanoparticles (AgNPs) were examined. Methods: Evaluating the efficacy of the VD2+AgNP cream in wound healing, skin irritation and UVB irradiation protection necessitated preclinical testing using reconstructed human skin equivalent models (prepared from human foreskins) containing both a fully stratified epidermal layer and underlying dermis. Results: Application of the cream significantly improved wound healing by stimulating keratinocyte re-epithelialization and dermal fibroblast migration in models subjected to full-thickness (scratch and biopsy punch) wounds, compared to untreated models. The VD2+AgNP cream, administered prior to the induction of skin irritation by 5% sodium dodecyl sulfate (SDS) afforded protection by ameliorating cell viability epidermal thickness and interleukin-1alpha levels. UVB exposure (50 mJ/cm2) significantly reduced cell viability and epidermal thickness (associated with increased epidermal breakage), as well as basal layer Ki67 and supra-basal layer involucrin expression, compared to the CTRL sham-irradiated models. The cream administered prior to UVB irradiation (protective capacity) showed greater efficacy in minimizing epidermal damage. This was reflected by significantly higher Ki67 and involucrin expression, as well as lower epidermal breakage, compared to models where the cream was applied following UVB irradiation (curative capacity). Conclusions: The VD2+AgNP cream shows multipurpose potential in skin protection. The underlying molecular mechanisms remain to be investigated. Full article
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25 pages, 10006 KiB  
Article
Nasal Spray Disinfectant for Respiratory Infections Based on Functionalized Silver Nanoparticles: A Physicochemical and Docking Approach
by Benjamín Valdez-Salas, Jorge Salvador-Carlos, Ernesto Valdez-Salas, Ernesto Beltrán-Partida, Jhonathan Castillo-Saenz, Mario Curiel-Álvarez, Daniel Gonzalez-Mendoza and Nelson Cheng
Nanomaterials 2025, 15(7), 533; https://doi.org/10.3390/nano15070533 - 31 Mar 2025
Viewed by 663
Abstract
Respiratory diseases have presented a remarkable challenge during modern history, contributing to important pandemics. The scientific community has focused its efforts on developing vaccines and blocking the transmission of viruses through the respiratory tract. In this study, we propose the use of stable [...] Read more.
Respiratory diseases have presented a remarkable challenge during modern history, contributing to important pandemics. The scientific community has focused its efforts on developing vaccines and blocking the transmission of viruses through the respiratory tract. In this study, we propose the use of stable silver nanoparticles (AgNPs) functionalized with tannic acid (TA) and sodium citrate (SC) as a nasal spray disinfectant (NSD). The non-ionic ethoxylated surfactant Tween 80 (T80) was added to enhance the wetting effect on nasal and oral tissues following spray application. We analyzed the physicochemical properties of the AgNPs and the NSD, including zeta potential, polarity, morphology, composition, particle size, and distribution. The results indicated spherical AgNPs ranging from 3 to 5 nm, stabilized by TA-SC. The addition of T80 resulted in particles with negative polarity, high stability, and improved coverage area. Furthermore, the colloidal stability was monitored over one year, showing no signs of degradation or precipitation. Interestingly, the interaction between the capped AgNP complex, the spike protein, and ACE2 was studied by molecular docking, indicating a strong and thermodynamically favorable complex interaction. These findings hold promise for the development of potential inhibitors, antagonist receptors, Ag-complex agonists (as observed here), and drug development for viral protection. Full article
(This article belongs to the Section Nanocomposite Materials)
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24 pages, 5754 KiB  
Article
Green Synthesis of Silver Nanoparticles from Chlorella vulgaris Aqueous Extract and Their Effect on Salmonella enterica and Chicken Embryo Growth
by Sebastian Michalec, Wiktoria Nieckarz, Wiktoria Klimek, Agata Lange, Arkadiusz Matuszewski, Klara Piotrowska, Anna Hotowy, Małgorzata Kunowska-Slósarz and Malwina Sosnowska
Molecules 2025, 30(7), 1521; https://doi.org/10.3390/molecules30071521 - 29 Mar 2025
Cited by 3 | Viewed by 1335
Abstract
Silver nanoparticles (AgNPs), synthesised using Chlorella vulgaris algal extract and silver nitrate, are studied in medicine for their antibacterial properties in poultry. This study assessed the effect of AgNPs on bacterial inhibition and early development and blood parameters in Ross 308 chicken embryos. [...] Read more.
Silver nanoparticles (AgNPs), synthesised using Chlorella vulgaris algal extract and silver nitrate, are studied in medicine for their antibacterial properties in poultry. This study assessed the effect of AgNPs on bacterial inhibition and early development and blood parameters in Ross 308 chicken embryos. AgNPs were characterised using transmission electron microscopy, scanning electron microscopy with a focused ion beam, UV–Vis spectroscopy, and a zetasizer. The antibacterial properties of the AgNP colloid against S. enterica were assessed using minimal inhibitory concentration, minimal bacterial concentration, and PrestoBlue assays. AgNP colloid (2 mg/L) was injected into egg albumen on day 0. Chicken embryos were incubated for 3 and 16 d. The effect of AgNPs on 3 d old embryos was evaluated based on mortality and somite count using the Hamburger–Hamilton classification. For older embryos, mortality, dimensions, anatomical changes, organ mass, plasma liver enzymes and antioxidants, and red blood cell morphology were determined. Blood samples from the control group embryos were assessed for the impact of AgNPs on hemolysis. AgNPs inhibited S. enterica growth at concentrations >6.75 mg/L. A 3 d exposure to AgNPs caused an insignificant decrease in the number of somites without affecting embryo mortality. However, a 16 d exposure to AgNPs reduced live embryos and plasma antioxidants, changed the levels of ALT, AST, and GGT, altered red blood cell morphology, and caused hemolysis. Toxicity of AgNPs was model-dependent, whereby the chicken embryo was more sensitive to AgNPs than the bacterium. Full article
(This article belongs to the Special Issue Synthesis of Nanomaterials and Their Applications in Biomedicine)
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19 pages, 8471 KiB  
Article
Green Nanoparticle Synthesis in the Application of Non-Bacterial Mastitis in Cattle
by Michał Motrenko, Agata Lange, Aleksandra Kalińska, Marcin Gołębiewski, Małgorzata Kunowska-Slósarz, Barbara Nasiłowska, Joanna Czwartos, Wojciech Skrzeczanowski, Aleksandra Orzeszko-Rywka, Tomasz Jagielski, Anna Hotowy, Mateusz Wierzbicki and Sławomir Jaworski
Molecules 2025, 30(6), 1369; https://doi.org/10.3390/molecules30061369 - 18 Mar 2025
Viewed by 885
Abstract
This study explores the potential of silver nanoparticles (AgNPs) synthesized through an eco-friendly method using coffee extract to combat non-bacterial mastitis in dairy cattle. Mastitis, often caused by pathogens such as yeasts and algae like Prototheca spp., poses a challenge due to the [...] Read more.
This study explores the potential of silver nanoparticles (AgNPs) synthesized through an eco-friendly method using coffee extract to combat non-bacterial mastitis in dairy cattle. Mastitis, often caused by pathogens such as yeasts and algae like Prototheca spp., poses a challenge due to the limited efficacy of traditional antibiotics. This research utilized strains isolated from mastitis milk and assessed the nanoparticles’ physicochemical properties, antimicrobial efficacy, and impact on biofilm formation and microorganism invasion. AgNPs demonstrated a spherical shape with a mean hydrodynamic diameter of ~87 nm and moderate colloidal stability. Antimicrobial tests revealed significant growth inhibition of yeast and Prototheca spp., with minimal inhibitory concentrations (MICs) as low as 10 mg/L for certain strains. Biofilm formation was notably disrupted, and microorganism invasion in bioprinted gels was significantly reduced, indicating the broad-spectrum potential of AgNPs. The study highlights the nanoparticles’ ability to damage cell membranes and inhibit metabolic activities, presenting a promising alternative for managing infections resistant to conventional treatments. These findings suggest that green-synthesized AgNPs could play a pivotal role in developing sustainable solutions for mastitis treatment, particularly for pathogens with limited treatment options. Full article
(This article belongs to the Special Issue Advanced Functional Nanomaterials in Medicine and Health Care)
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13 pages, 3220 KiB  
Article
Utilizing Freeze-Thaw-Ultrasonication to Prepare Mesoporous Silica-Encapsulated Colloidal Silver Nanoaggregates with Long-Term Surface-Enhanced Raman Spectroscopy Activity
by Shuoyang Yan, Ling Chen and Zhiyang Zhang
Sensors 2025, 25(6), 1840; https://doi.org/10.3390/s25061840 - 15 Mar 2025
Viewed by 624
Abstract
Surface-enhanced Raman spectroscopy (SERS) is widely employed due to its high sensitivity and distinctive fingerprinting capabilities. Colloidal nanoaggregates are commonly used as SERS substrates because of their mobility and the abundance of “hotspots”. Although the reagent-free “freeze-thaw-ultrasonication” method for preparing Ag nanoaggregates (AgNAs) [...] Read more.
Surface-enhanced Raman spectroscopy (SERS) is widely employed due to its high sensitivity and distinctive fingerprinting capabilities. Colloidal nanoaggregates are commonly used as SERS substrates because of their mobility and the abundance of “hotspots”. Although the reagent-free “freeze-thaw-ultrasonication” method for preparing Ag nanoaggregates (AgNAs) does not introduce additional background interference and maintains the original interfacial properties of AgNAs, their unstable physical nanostructure limits SERS detection to just 7 days. Herein, we demonstrate mesoporous silica-encapsulated colloidal Ag nanoaggregates (AgNAs@m-SiO2) by combining a freeze-thaw-ultrasonication method and a cetyltrimethylammonium bromide (CTAB)-assisted silanization reaction, achieving long-term SERS stability of more than two months. The prepared AgNAs@m-SiO2 serve a dual capability: (1) preserving electromagnetic “hotspots” for ultra-sensitive detection (e.g., malachite green detection limit: 3.60 × 108 M), and (2) maintaining structural stability under harsh conditions. The AgNAs@m-SiO2 substrate exhibited superior structural stability after 50 min of ultrasonic treatment, with an initial SERS signal retention of 91.8%, which is twice that of the bare AgNAs (retention of 45%). The long-term performance further highlighted its superiority: after 70 days of storage, the composite maintained 84.3% of its original signal strength, outperforming the uncoated controls by over ten times (which retained only 8%). Crucially, the substrate’s robust design enables the direct detection of contaminants in real environmental matrices (river and seawater) for qualitative analyses and water quality assessments, thus validating its suitability for environmental sensing applications in the field. Full article
(This article belongs to the Special Issue Nanotechnology Applications in Sensors Development)
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