Search Results (70)

In this study, we report the development of a novel magnetized coal fly ash-supported nano-silver composite (AgNPs/MCFA) for dual-functional applications in wastewater treatment: the efficient degradation of methyl orange (MO) dye and broad-spectrum antibacterial activity. The composite was synthesized via a facile impregnation–reduction–sintering route, utilizing sodium citrate as both a reducing and stabilizing agent. The AgNPs/MCFA composite was systematically characterized through multiple analytical techniques, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). The results confirmed the uniform dispersion of AgNPs (average size: 13.97 nm) on the MCFA matrix, where the formation of chemical bonds (Ag-O-Si) contributed to the enhanced stability of the material. Under optimized conditions (0.5 g·L⁻¹ AgNO₃, 250 °C sintering temperature, and 2 h sintering time), AgNPs/MCFA exhibited an exceptional catalytic performance, achieving 99.89% MO degradation within 15 min (pseudo-first-order rate constant k_a = 0.3133 min⁻¹) in the presence of NaBH₄. The composite also demonstrated potent antibacterial efficacy against Escherichia coli (MIC = 0.5 mg·mL⁻¹) and Staphylococcus aureus (MIC = 2 mg·mL⁻¹), attributed to membrane disruption, intracellular content leakage, and reactive oxygen species generation. Remarkably, AgNPs/MCFA retained >90% catalytic and antibacterial efficiency after five reuse cycles, enabled by its magnetic recoverability. By repurposing industrial waste (coal fly ash) as a low-cost carrier, this work provides a sustainable strategy to mitigate nanoparticle aggregation and environmental risks while enhancing multifunctional performance in water remediation. Full article

Background/Objectives: Trimethoprim (TMP), a sulfonamide antibacterial synergist, is widely used in antimicrobial therapy owing to its broad-spectrum activity and clinical efficacy in treating respiratory, urinary tract, and gastrointestinal infections. However, its application is limited due to poor aqueous solubility, a short elimination half-life (t_1/2), and low bioavailability. In this study, we proposed TMP loaded by PEG-PLGA polymer nanoparticles (NPs) to increase its efficacy. Methods: We synthesized and thoroughly characterized PEG-PLGA NPs loaded with TMP using an oil-in-water (O/W) emulsion solvent evaporation method, denoted as PEG-PLGA/TMP NPs. Drug loading capacity (LC) and encapsulation efficiency (EE) were quantified by ultra-performance liquid chromatography (UPLC). Comprehensive investigations were conducted on the stability of PEG-PLGA/TMP NPs, in vitro drug release profiles, and in vivo pharmacokinetics. Results: The optimized PEG-PLGA/TMP NPs displayed a high LC of 34.0 ± 1.6%, a particle size of 245 ± 40 nm, a polydispersity index (PDI) of 0.103 ± 0.019, a zeta potential of −23.8 ± 1.2 mV, and an EE of 88.2 ± 4.3%. The NPs remained stable at 4 °C for 30 days and under acidic conditions. In vitro release showed sustained biphasic kinetics and enhanced cumulative release, 86% at pH 6.8, aligning with first-order models. Pharmacokinetics in rats revealed a 2.82-fold bioavailability increase, prolonged half-life 2.47 ± 0.19 h versus 0.72 ± 0.08 h for free TMP, and extended MRT 3.10 ± 0.11 h versus 1.27 ± 0.11 h. Conclusions: PEG-PLGA NPs enhanced the solubility and oral bioavailability of TMP via high drug loading, stability, and sustained-release kinetics, validated by robust in vitro-in vivo correlation, offering a promising alternative for clinical antimicrobial therapy. Full article

This study aimed to design dual-responsive chitosan–polylactic acid nanosystems (PLA@CS NPs) for controlled and targeted ledipasvir (LED) delivery to HepG2 liver cancer cells, thereby reducing the systemic toxicity and improving the therapeutic selectivity. Two formulations were developed utilizing ionotropic gelation and w/o/w emulsion techniques: LED@CS NPs with a size of 143 nm, a zeta potential of +43.5 mV, and a loading capacity of 44.1%, and LED-PLA@CS NPs measuring 394 nm, with a zeta potential of +33.3 mV and a loading capacity of 89.3%, with the latter demonstrating significant drug payload capacity. Since most drugs work through interaction with DNA, the in vitro affinity of DNA to LED and its encapsulated forms was assessed using stopped-flow and other approaches. They bind through multi-modal electrostatic and intercalative modes via two reversible processes: a fast complexation followed by a slow isomerization. The overall binding activation parameters for LED (cordination affinity, K_a = 128.4 M⁻¹, K_d = 7.8 × 10⁻³ M, ΔG = −12.02 kJ mol⁻¹), LED@CS NPs (K_a = 2131 M⁻¹, K_d = 0.47 × 10⁻³ M, ΔG = −18.98 kJ mol⁻¹) and LED-PLA@CS NPs (K_a = 22026 M⁻¹, K_d = 0.045 × 10⁻³ M, ΔG = −24.79 kJ mol⁻¹) were obtained with a reactivity ratio of 1/16/170 (LED/LED@CS NPs/LED-PLA@CS NPs). This indicates that encapsulation enhanced the interaction between the DNA and the LED-loaded nanoparticle systems, without changing the mechanism, and formed thermodynamically stable complexes. The drug release kinetics were assessed under tumor-mimetic conditions (pH 5.5, 10 mM GSH) and physiological settings (pH 7.4, 2 μM GSH). The LED@CS NPs and LED-PLA@CS NPs exhibited drug release rates of 88.0% and 73%, respectively, under dual stimuli over 50 h, exceeding the release rates observed under physiological conditions, which were 58% and 54%, thereby indicating that the LED@CS NPs and LED-PLA@CS NPs systems specifically target malignant tissue. Release regulated by Fickian diffusion facilitates tumor-specific payload delivery. Although encapsulation did not enhance the immediate cytotoxicity compared to free LED, as demonstrated by an in vitro cytotoxicity in HepG2 cancer cell lines, it significantly enhanced the therapeutic index (2.1-fold for LED-PLA@CS NPs) by protecting non-cancerous cells. Additionally, the nanoparticles demonstrated broad-spectrum antibacterial effects, suggesting efficacy in the prevention of chemotherapy-related infections. The dual-responsive LED-PLA@CS NPs allowed controlled tumor-targeted LED delivery with better selectivity and lower off-target toxicity, making LED-PLA@CS NPs interesting candidates for repurposing HCV treatments into safer cancer nanomedicines. Furthermore, this thorough analysis offers useful reference information for comprehending the interaction between drugs and DNA. Full article

Background/Objectives: The rise of bacterial resistance and the search for alternative, biocompatible antimicrobial materials have driven interest in natural-based nanocomposites. In this context, silver nanoparticles (AgNPs) have shown broad-spectrum antibacterial activity, and bacterial cellulose (BC) is widely recognized for its high purity, hydrophilicity, and biocompatibility. This study aimed to develop a bio-based BC–AgNP nanocomposite via green synthesis using Astrocaryum aculeatum (tucumã) extract and assess its antimicrobial performance for wound dressing applications. Methods: BC was biosynthesized via green tea fermentation (20 g/L tea and 100 g/L sugar) and purified prior to use. AgNPs were obtained by reacting aqueous tucumã extract with silver nitrate (0.1 mmol/L) at pH (9) and temperature (40 °C). BC membranes were immersed in the AgNPs dispersion for 7 days to form the nanocomposite. Characterization was performed using UV–Vis, DLS, TEM, SEM–EDS, FTIR, XRD, ICP–OES, and swelling analysis. Antibacterial activity was evaluated using the disk diffusion method against Staphylococcus aureus and Escherichia coli (ATCC 6538 and 4388). Results: The UV–Vis spectra revealed a gradual decrease in the surface plasmon resonance (SPR) band over 7 days of incubation with BC, indicating progressive incorporation of AgNPs into the membrane. ICP analysis confirmed silver incorporation in the BC membrane at 0.00215 mg/mL, corresponding to 15.5% of the initial silver content. Antimicrobial assays showed inhibition zones of 6.5 ± 0.5 mm for S. aureus and 4.3 ± 0.3 mm for E. coli. Conclusions: These findings validate the successful formation and antimicrobial performance of the BC–AgNP nanocomposite, supporting its potential use in wound care applications. Full article

Silver nanoparticles (AgNPs) have emerged as a promising antimicrobial agent in dentistry due to their distinctive physicochemical characteristics and broad-spectrum biocidal activity. For example, silver nanoparticles can be incorporated into oral hygiene products in preventive dentistry, composite resins in restorative treatment, irrigation solutions in endodontic treatment, membranes for guided tissue regeneration in periodontal treatment, acrylic resins and porcelains in prosthodontic treatment, coatings in dental implant treatment, and brackets and wires in orthodontic treatment. This paper focuses on summarizing the current knowledge on the antimicrobial use of silver nanoparticles in dentistry, highlighting their antimicrobial mechanism and potential applications in clinical treatment. The literature indicates that silver nanoparticles are a promising antimicrobial agent in dentistry. However, there are still many issues including fundamental antibacterial mechanisms that need to be completely elucidated before clinical applications. Full article

Chronic wounds not only cause significant patient morbidity but also impose a substantial economic burden on the healthcare system. The primary barriers to wound healing include a deficiency of key modulatory factors needed to progress beyond the stalled inflammatory phase and an increased susceptibility to infections. While antimicrobial agents have traditionally been used to treat infections, stem cells have recently emerged as a promising therapy due to their regenerative properties, including the secretion of cytokines and immunomodulators that support wound healing. This study aims to develop an advanced dual-delivery system integrating stem cells and antibiotics. Stem cells have previously been delivered by encapsulation in gelatin methacrylate (GelMA) hydrogels. To explore a more effective delivery method, GelMA was processed into microparticles (MP). Compared to a bulk GelMA hydrogel (HG) encapsulation, GelMA MP supported greater cell growth and enhanced in vitro wound healing activity of human mesenchymal stem cells (hMSCs), likely due to a larger surface area for cell attachment and improved nutrient exchange. To incorporate antimicrobial properties, the broad-spectrum antibiotics penicillin/streptomycin (PS) were loaded into a bulk GelMA hydrogel, which was then cryo-milled into MPs to serve as carriers for hMSCs. To achieve a more sustained antibiotic release, gelatin nanoparticles (NP) were used as carriers for PS. PS was either incorporated during NP synthesis (NP+PS(S)) or absorbed into NP after synthesis (NP+PS(A)). MPs containing PS, NP+PS(S), or NP+PS(A) were tested for their cell carrier functions and antibacterial activities. The incorporation of PS did not compromise the cell-carrying function of MP configurations. The anti-S. aureus activity was detected in conditioned media from MPs for up to eight days—four days longer than from bulk HG containing PS. Notably, the presence of hMSCs prolonged the antimicrobial activity of MPs, suggesting a synergistic effect between stem cells and antibiotics. PS loaded via synthesis (NP+PS(S)) exhibited a delayed initial release, whereas PS loaded via absorption (NP+PS(A)) provided a more immediate release, with potential for sustained delivery. This study demonstrates the feasibility of a dual-delivery system integrating thera Full article

Complex wounds pose a significant healthcare challenge due to their susceptibility to infections and delayed healing. This study focuses on developing electrospun polycaprolactone (PCL) nanofiber membranes coated with Type I collagen derived from bovine skin and functionalized with silver nanoparticles (AgNPs) to address these issues. The collagen coating enhances biocompatibility, while AgNPs synthesized through chemical reduction with sodium citrate provide broad-spectrum antimicrobial properties. The physical properties of the membranes were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Results showed the formation of nanofibers without defects and the uniform distribution of AgNPs. A swelling test and contact angle measurements confirmed that the membranes provided an optimal environment for wound healing. In vitro biological assays with murine 3T3 fibroblasts revealed statistically significant (p ≤ 0.05) differences in cell viability among the membranes at 24 h (p = 0.0002) and 72 h (p = 0.022), demonstrating the biocompatibility of collagen-coated membranes and the minimal cytotoxicity of AgNPs. Antibacterial efficacy was evaluated against Staphylococcus aureus (SA), Pseudomonas aeruginosa (PA), and Vancomycin-resistant Enterococcus (VRE), with the significant inhibition of biofilm formation observed for VRE (p = 0.006). Overall, this novel combination of collagen-coated electrospun PCL nanofibers with AgNPs offers a promising strategy for advanced wound dressings, providing antimicrobial benefits. Future in vivo studies are warranted to further validate its clinical and regenerative potential. Full article

Aeromonas species are among the main pathogens causing rainbow trout infections. Silver nanoparticles (AgNPs) have a broad spectrum of antimicrobial properties and are usually produced by various green-synthesis methods. However, the application of commercialized AgNPs has not fully been clarified. Thus, the objective of this study was to evaluate the antibacterial activities of commercialized AgNPs (range of sizes 10–12 nm) on two contrasting A. salmonicida strains (I-1 and I-4), isolated from rainbow trout; the antibacterial mechanism, histopathological alterations and the expression of immune-related genes were investigated. In vitro, the minimal inhibitory concentration (MIC) was 10 µg/mL for I-1, and lowered to 9.5 µg/mL for I-4, respectively. AgNPs were shown to disrupt both the cell wall and membrane of I-1 and I-4, resulting in cell lysis and degradation. In vivo, rainbow trout challenged by immersed or intraperitoneally injected infection, the 10 µg/mL AgNP-treated groups, both showed delayed deaths and lower mortalities compared to the control groups, without any clinical signs and pathological changes. Especially for the virulent I-4, the enhanced expressions of immune-related genes TNF-α, IL-1β, IL-10 and IL-11 were significantly reduced in the AgNP-treated group, indicating a lesser inflammation due to the application of AgNPs. This study would lay theoretical foundation for the wide application of silver nanoparticles in fish diseases. Full article

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

Background: Green synthesized nanoparticles (NPs) have gained increasing popularity in recent times due to their broad spectrum of antimicrobial properties. This study aimed to develop a phytofabrication approach for producing cuprous (Cu₂O) and cupric oxide (CuO) NPs using a simple, non-hazardous process and to examine their antimicrobial properties. Methods: The synthesis employed Bidens pilosa plant extract as a natural reducing and stabilizing agent, alongside copper chloride dihydrate as the precursor. The biosynthesized NPs were characterized through various techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectroscopy, ultraviolet–visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Results: XRD analysis confirmed that the synthesized CuO and Cu₂O NPs exhibited a high degree of crystallinity, with crystal structures corresponding to monoclinic and face-centered cubic systems. SEM images revealed that the NPs displayed distinct spherical and sponge-like morphologies. EDS analysis further validated the purity of the synthesized CuO NPs. The antimicrobial activity of the CuO and Cu₂O NPs was tested against various pathogenic bacterial strains, including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Bacillus cereus, with the minimum inhibitory concentration (MIC) used to gauge their effectiveness. Conclusions: The results showed that the phytosynthesized NPs had promising antibacterial properties, particularly the Cu₂O NPs, which, with a larger crystal size of 68.19 nm, demonstrated significant inhibitory effects across all tested bacterial species. These findings suggest the potential of CuO and Cu₂O NPs as effective antimicrobial agents produced via green synthesis. Full article

N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC), a quaternized chitosan derivative, has been shown to exhibit a broad spectrum of antimicrobial activity, especially against bacteria and enveloped viruses. Despite this, molecular docking studies showing its atomic-level mechanisms against these microorganisms are scarce. Here, for the first time, we employed molecular docking analyses to investigate the potential antibacterial activity of HTCC against Staphylococcus aureus and its antiviral activity against human immunodeficiency virus 1 (HIV-1). According to the findings, HTCC exhibited promising antibacterial activity with high binding affinities; however, it had limited antiviral activity. To validate these theoretical outcomes, experimental studies were conducted. Different derivatives of HTCC were synthesized and characterized using NMR, XRD, FTIR, and DLS. The in vitro assays validated the potent antibacterial efficacy of HTCC against S. aureus, whereas the antiviral studies did not show good antiviral activity. However, our research also revealed a promising avenue for further exploration of the antimicrobial activity of HTCC nanoparticles (NPs), since, thus far, no studies have been conducted to show the antiviral activity of HTCC NPs against HIV-1. The nanosized HTCC exhibited superior antiviral performance compared to the parent polymers, with complete (100%) inhibition of HIV-1 viral activity at the highest tested concentration (0.33 mg/mL). Full article

This study investigates the development and application of electrospun wound dressings based on polylactic acid (PLA) nanofibers, chitosan, and copper nanoparticles (CuNPs) for the treatment of purulent skin wounds. The materials were evaluated for their structural, antibacterial, and wound healing properties using an animal model. PLA/Ch-CuNPs demonstrated the most significant antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, surpassing the other tested materials. The integration of CuNPs into the nanofiber matrices not only enhanced the antimicrobial efficacy but also maintained the structural integrity and biocompatibility of the dressings. In vivo experiments using a rat model showed that PLA/Ch-CuNPs facilitated faster wound healing with reduced exudative and inflammatory responses compared to PLA alone or PLA-CuNPs. Histological and immunohistochemical assessments revealed that the combination of PLA, chitosan, and CuNPs mitigated the inflammatory processes and promoted tissue regeneration more effectively. However, this study identified potential toxicity related to copper ions, emphasizing the need for careful optimization of CuNP concentrations. These findings suggest that PLA/Ch-CuNPs could serve as a potent, cost-effective wound dressing with broad-spectrum antibacterial properties, addressing the challenge of antibiotic-resistant infections and enhancing wound healing outcomes. Full article

Latex of C. gigantea was used to synthesize zinc oxide nanoparticles (ZnO NPs) by the green chemistry approach. The crystalline size, shape, and purity of as-synthesized ZnO NPs were characterized through scanning electron microscopy with energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction analysis, and Fourier-transform infrared spectroscopy techniques. Crystalline, spherical ZnO NPs with an average size of 21.8 nm were formed. In addition, the biological properties of the ZnO NPs, such as antioxidant and antibacterial activity, were evaluated by 2,2-diphenyl-1-picrylhydrazyl assay and the agar well-diffusion method. The highest free radical scavenging activities of 83.11 ± 1.89 % were observed at a concentration of 350 μg/mL of C. gigantea latex-mediated ZnO NPs. The latex in the C. gigantea latex-mediated ZnO NPs inhibited the growth of pathogenic bacteria. The maximum zone of inhibition was found in P. aeruginosa and S. aureus. C. gigantea latex-mediated ZnO NPs have significant biocompatibility and broad-spectrum antibacterial properties against wound-causing bacteria and, therefore, can be suggested for use in the formulation of novel creams or gels for healing applications. Full article

AgCu bimetallic· nanoparticles (NPs) represent a novel class of inorganic, broad-spectrum antimicrobial agents that offer enhanced antimicrobial effectiveness and reduced cytotoxicity compared to conventional Ag NP antibacterial materials. This study examines the antimicrobial performance and structural characteristics of AgCu nanoparticles (NPs) synthesized via two distinct chemical reduction processes using PVP-PVA as stabilizers. Despite identical chemical elements and sphere-like shapes in both synthesis methods, the resulting AgCu nanoparticles exhibited significant differences in size and antimicrobial properties. Notably, AgCu NPs with smaller average particle sizes demonstrated weaker antimicrobial activity, as assessed by the minimum inhibitory concentration (MIC) measurement, contrary to conventional expectations. However, larger average particle-sized AgCu NPs showed superior antimicrobial effectiveness. High-resolution transmission electron microscopy analysis revealed that nearly all larger particle-sized nanoparticles were AgCu nanoalloys. In contrast, the smaller particle-sized samples consisted of both AgCu alloys and monometallic Ag and Cu NPs. The fraction of Ag ions (relative to the total silver amount) in the larger AgCu NPs was found to be around 9%, compared to only 5% in that of the smaller AgCu NPs. This indicates that the AgCu alloy content significantly contributes to enhanced antibacterial efficacy, as a higher AgCu content results in the increased release of Ag ions. These findings suggest that the enhanced antimicrobial efficacy of AgCu NPs is primarily attributed to their chemical composition and phase structures, rather than the size of the nanoparticles. Full article

This study addresses the need for enhanced antimicrobial properties of electrospun membranes, either through surface modifications or the incorporation of antimicrobial agents, which are crucial for improved clinical outcomes. In this context, chitosan—a biopolymer lauded for its biocompatibility and extracellular matrix-mimicking properties—emerges as an excellent candidate for tissue regeneration. However, fabricating chitosan nanofibers via electrospinning often challenges the preservation of their structural integrity. This research innovatively develops a chitosan/polycaprolactone (CH/PCL) composite nanofibrous membrane by employing a layer-by-layer electrospinning technique, enhanced with silver nanoparticles (AgNPs) synthesized through a wet chemical process. The antibacterial efficacy, adhesive properties, and cytotoxicity of electrospun chitosan membranes were evaluated, while also analyzing their hydrophilicity and nanofibrous structure using SEM. The resulting CH/PCL-AgNPs composite membranes retain a porous framework, achieve balanced hydrophilicity, display commendable biocompatibility, and exert broad-spectrum antibacterial activity against both Gram-negative and Gram-positive bacteria, with their efficacy correlating to the AgNP concentration. Furthermore, our data suggest that the antimicrobial efficiency of these membranes is influenced by the timed release of silver ions during the incubation period. Membranes incorporated starting with AgNPs at a concentration of 50 µg/mL effectively suppressed the growth of both microorganisms during the early stages up to 8 h of incubation. These insights underscore the potential of the developed electrospun composite membranes, with their superior antibacterial qualities, to serve as innovative solutions in the field of tissue engineering. Full article