Search Results (3,295)

Polyaniline-cadmium sulfide-gold (PANI-CdS-Au) nanocomposites were synthesized with varying Au loadings (0.023, 0.046, 0.092 wt%) to enhance antibacterial performance. Structural (FTIR, XRD) and morphological (FESEM) analyses confirmed successful formation, with nearly homogeneous nanoparticle distribution (27–53 nm) and slight XRD peak shifts indicating interfacial interactions between PANI, CdS, and Au. UV–Vis spectra revealed gold surface plasmon resonance and polaronic transitions consistent with PANI emeraldine base. XRD results showed the expected wurtzite CdS and fcc Au phases. Agar well diffusion tests against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) demonstrated that the 0.092 wt% of Au composite produced the largest inhibition zones at 100 µg mL⁻¹ (E. coli: 36 mm; S. aureus: 24 mm), with the same trend at 25 µg mL⁻¹. The results indicate that PANI–CdS/Au nanocomposites are promising antibacterial materials; however, the presence of CdS necessitates additional cytotoxicity assays to confirm their suitability for medical applications. Full article

Zirconia is known as a strong and bioinert load-bearing material for dental implants. It typically exhibits no antibacterial activity. Inflammation is a crucial problem for dental implant surgery: about 3–5% of all dental implants experience inflammation. This study demonstrates that either fullerene C₆₀ films or a tribomechanical loading of zirconia without the fullerene C₆₀ coating can cause an improvement in antibacterial activity against Gram-positive Staphylococcus aureus. This moderate antibacterial activity is especially important, because a strong antibacterial effect could disturb the sensitive and beneficial oral bacterial biota. In the present study, different fullerene C₆₀ films were examined. In addition to fullerene C₆₀ film in an “as deposited” condition, treatment with nitrogen plasma as well as tribomechanical produced surface patterns with and without plasma post-treatment were tested. An 85.8% (log reduction 0.85) reduction in Gram-positive Staphylococcus aureus bacterial formation was observed on the zirconia with fullerene C₆₀ film. Plasma treatment of the C₆₀ film increases the antibacterial impact to 72.2% (log reduction 0.56) in comparison to zirconia without fullerene C₆₀ film. Also, tribomechanical loaded fullerene C₆₀ films suppress the growth of Gram-positive Staphylococcus aureus. The tribomechanical loading seems to compensate for the effect of the plasma treatment. ZrO₂ samples with fullerene C₆₀ film and tribomechanical loading achieve an increase in antibacterial impact of 83.36% (log reduction 0.78). Furthermore, surprisingly yttria-stabilized zirconia bioceramic without fullerene C₆₀ film also shows an improved antibacterial efficacy after a tribomechanical patterning procedure. The addition of surface patterning on the ZrO₂ by scratching microgroove arrangements with a diamond tip, increased the antibacterial effect against Gram-positive Staphylococcus aureus by 70.46% (log reduction 0.53). Full article

Modification of PLA with functional nanoparticles is a promising approach for imparting new properties to the material. In this work, titanium nanoparticles (Ti NPs) and titanium dioxide nanoparticles (TiO₂ NPs) were synthesized by laser ablation and characterized by dynamic light scattering, spectrophotometry, and transmission electron microscopy. The average hydrodynamic diameter of Ti NPs was 12 nm, while that of TiO₂ NPs was 24 nm; both dispersions possessed a positive zeta potential (23–27 mV) and spherical morphology. L-PLA composite films containing 0.1 wt.% Ti NPs or TiO₂ NPs were obtained by solution casting. Atomic force and modulation-interference microscopy confirmed the uniform distribution of nanoparticles within the polymer matrix, although partial aggregation was observed. The introduction of TiO₂ NPs increased the water contact angle. Mechanical testing revealed a significant reinforcing effect: the addition of 0.1 wt.% NPs increased the Young’s modulus by 62–68% and the ultimate tensile strength by 16–18% while maintaining a ductile fracture pattern with elongation at break up to ~8%. Both types of composites generated reactive oxygen species (ROS) in aqueous solutions: Ti NPs increased H₂O₂ production by 5.5 times and TiO₂ NPs by 4.9 times, and they also induced the formation of hydroxyl radicals. The accumulation of 8-oxoguanine in DNA and long-lived oxidized protein species confirmed the materials’ ability to cause oxidative damage to biomacromolecules. For E. coli, growth inhibition reached 40.5% (for composites with Ti NPs) and 71% (for composites with TiO₂ NPs). The effect was even more pronounced for S. aureus, where inhibition levels were approximately 70% and 80%, respectively; flow cytometry confirmed the strong bactericidal effect, showing that materials containing TiO₂ NPs increased the proportion of dead cells to 25% for E. coli and ~68% for S. aureus. Cytotoxicity assessment on human fibroblasts (HSF) demonstrated the high biocompatibility of neat L-PLA and composites with Ti NPs (viability > 95%) and with TiO₂ NPs (viability ~93%). The obtained results indicate that L-PLA-based composites with Ti NPs and TiO₂ NPs exhibit pronounced ROS-mediated antibacterial activity without additional UV irradiation. These findings position these materials as highly promising candidates for active biodegradable food packaging to extend shelf-life and for biomedical devices, such as wound dressings and implants, where reducing the risk of bacterial colonization is critical. Full article

In this research, PLA biocomposites reinforced with 20 wt% flax fibers modified with 1, 5, 10, and 20% concentrations of trans-cinnamic acid (TC) were prepared. The materials were systematically characterized to evaluate their structural, thermal, viscoelastic, surface, and functional properties. Thermal stability and phase transitions were analyzed using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC), while viscoelastic behavior and molecular relaxation processes were investigated by dynamic mechanical analysis (DMA). To elucidate failure mechanisms and interfacial quality, fracture surface morphology after tensile testing was observed using scanning electron microscopy (SEM). Surface wettability was determined through water contact angle measurements, and antibacterial activity against Escherichia coli and Staphylococcus aureus was evaluated to assess the functional potential of the developed biocomposites. The results demonstrated that moderate fiber modification improved interfacial adhesion and enhanced thermo-mechanical performance. The highest contact angles were observed for 5% and 10% TC concentrations, indicating increased surface hydrophobicity, while strong antibacterial activity (R ≥ 6) was achieved for 10% and 20% TC. The research confirms that trans-cinnamic acid concentration governs multiple structure–property relationships, enabling controlled tuning of mechanical reinforcement and antibacterial functionality. Full article

Antimicrobial resistance is a serious global public health concern, with Acinetobacter baumannii recognized as one of the most problematic multidrug-resistant (MDR) pathogens. This Gram-negative bacterium is highly persistent in the environment, possesses a remarkably adaptable cell envelope, and forms biofilms. As the effectiveness of conventional antibiotics declines, alternative strategies are being actively explored, particularly membrane-targeting approaches based on synthetic copolymers. These compounds mimic antimicrobial peptides, offer enhanced stability and structural tunability, and have a lower propensity to develop resistance. Recent advances in polymer chemistry have led to the design of antibacterial polymers with activity against MDR A. baumannii. Some of these act synergistically with existing antibiotics, restoring bacterial susceptibility or disrupting biofilms. However, their non-degradability remains a concern due to its potential implications for body/environment accumulation and related toxicity and/or selection of resistant strains. This review examines the biology of the A. baumannii cell envelope, its resistance mechanisms, and treatment limitations, while emphasizing the promise of membrane-active copolymers. By bridging materials science and microbiology, these approaches offer promising strategies for combating World Health Organization priority pathogens. Full article

Phellodendri amurensis Cortex is the dried bark of the cork tree (Phellodendron amurense Rupr.) from the Rutaceae family, and possesses traditional efficacy in clearing heat, drying dampness, purging fire, relieving steaming sensations, detoxifying, and healing sores. Clinically, it is commonly used for treating symptoms such as damp-heat diarrhea and dysentery, jaundice with reddish urine, leukorrhea with vaginal itching, painful and difficult urination due to heat strangury, flaccidity and weakness of the lower limbs, bone-steaming and consumptive fever, night sweats and seminal emission, sores, ulcers, swellings, and toxins, eczema, damp sores, and urinary tract infections. Modern pharmacological studies have further revealed its diverse bioactivities, including antioxidant, antibacterial, anti-inflammatory, immunosuppressive, and anticancer effects. To provide an updated and comprehensive review of the research into Phellodendri amurensis Cortex, this study conducted a thorough literature search and analysis based on databases such as SciFinder, Web of Science, and China National Knowledge Infrastructure. The review integrates information on the plant’s botanical characteristics, geographical distribution, traditional applications, chemical components, quality control methods, and pharmacological effects to present a current and holistic overview of its research status. To date, approximately 170 compounds have been isolated and identified from Phellodendri amurensis Cortex, primarily including alkaloids, phenolics, terpenoids, sterols, lignans, flavonoids, and others. Among these, alkaloids exhibit significant antioxidant and anti-inflammatory activities and demonstrate potential pharmacological value in antibacterial, anticancer, hypoglycemic, and multi-organ protective effects. Although substantial foundational research exists, the mechanisms of action and quality control of Phellodendri amurensis Cortex require further in-depth exploration. Future efforts should focus on clarifying its pharmacodynamic material basis, uncovering new targets and pathways, and improving analytical methods for component analysis and quality control to advance the scientific development and rational utilization of this medicinal material. Full article

The development of biodegradable, biocompatible materials with inherent antibacterial properties, suitable for 3D printing, is a key challenge in modern materials science. Composites based on PLA and copper nanoparticles (NPs) are promising candidates for such a material. A protocol of the low-temperature incorporation of 0.1% Cu NPs or 0.1% CuO NPs into a PLA was developed. The dependence of the materials’ physicochemical properties on nanoparticle composition was evaluated. Cu and CuO NPs were synthesized via liquid-phase laser ablation and had sizes of 25 and 80 nm, with modal zeta potential values of +31 and +42 mV, respectively. The incorporation of Cu NPs enhances the tensile strength and Young’s modulus of PLA, and improves antibacterial properties. The PLA + 0.1% CuO or PLA + 0.1% Cu nanoparticles inhibited the growth of E. coli by ~60% and >80%, respectively. PLA + 0.1% Cu NPs destructed of bacterial cell walls. The antibacterial action mechanisms are an 8-oxoguanine and LRPS generations. The obtained materials did not exhibit cytotoxic effects against normal human fibroblasts, did not alter the pH or redox potential of water, and did not release of Cu²⁺ in concentrations toxic to humans. The material PLA + 0.1% Cu NPs is the most optimal. This material may find applications in food production and biomedical applications. Full article

The rapid emergence of antibiotic-resistant bacteria represents one of the most critical challenges in modern healthcare and has stimulated intense research into alternative antimicrobial strategies. Antibacterial hydrogels have emerged as versatile biomaterials due to their high water content, tunable physicochemical properties, and ability to function as multifunctional platforms for drug delivery and tissue regeneration. This review analyzes recent advances in antibacterial hydrogel systems through a conceptual framework based on three complementary pillars: biological antibacterial agents, inorganic functional components, and structural material engineering. Biological strategies, particularly bacteriophage-based approaches, provide highly specific antibacterial activity capable of targeting multidrug-resistant pathogens and disrupting bacterial biofilms. Inorganic components such as hydroxyapatite nanoparticles contribute additional functionalities including drug adsorption, modulation of the ionic microenvironment, and osteoconductive behavior relevant for bone-related infections. Structural design strategies based on electrospinning enable the fabrication of fibrous architectures that enhance mechanical stability, regulate therapeutic release, and mimic extracellular matrix organization. The integration of these three pillars within multifunctional hydrogel platforms offers promising opportunities for developing advanced antibacterial biomaterials capable of addressing infection control while supporting tissue regeneration. Full article

Background and Objectives: Premature loss of primary teeth can disrupt occlusal development and oral function. Although iodoform-based materials such as Vitapex^® are widely used, concerns remain regarding their cytotoxicity and potential to accelerate root resorption. Sodium iodide (NaI) has emerged as a biocompatible, antibacterial alternative. This study evaluated the feasibility of a NaI-based root canal filling material in a canine model of Enterococcus faecalis-induced periapical inflammation. Methods: Periapical lesions were induced in a healthy male mongrel dog using E. faecalis (10⁶ CFU/mL). After six weeks, the root canals were obturated with NaI paste, Vitapex^®, or Calcipex. Untreated teeth and an E. faecalis-only group served as controls. Radiographic lesion sizes were monitored at 4, 8, 12, and 16 weeks post-obturation. Histological analysis at 16 weeks assessed inflammatory area and perimeter, stromal fibrosis, inflammatory cell infiltration, and myeloperoxidase (MPO) expression. Results: Radiographically, all treatment groups showed reduced lesion size relative to the positive control. No significant differences were observed among the NaI, Vitapex^®, and Calcipex groups at 4 and 8 weeks; however, significant differences emerged at 12 and 16 weeks (p < 0.05). The NaI group showed lesion reduction until week 8, followed by subsequent expansion thereafter, whereas the Vitapex^® and Calcipex groups showed continuous lesion reduction over time. Histologically, the periapical inflammatory area increased in the order of Vitapex^® < Calcipex < NaI < positive control (p < 0.05). MPO staining identified neutrophils as the primary inflammatory cells. Conclusions: NaI paste showed favorable early radiographic healing but limited long-term stability compared with conventional materials. With further optimization, it may have potential as an alternative root canal filling material. However, given the single-animal exploratory design, these findings should be interpreted as preliminary rather than definitive evidence. Full article

Modified chitosan (Cs) derivatives were synthesized and evaluated as potential antibacterial and antiviral coatings of medical protective equipment (facial masks, gloves, …). Quaternized chitosan (HTCC) and chitosan–silver nanocomposites (Ag/Cs) were successfully prepared, with structural characterization confirming efficient quaternization and uniform incorporation of silver nanoparticles. Antibacterial testing revealed that HTCC exhibited concentration-dependent activity, while Ag/Cs showed strong broad-spectrum antibacterial effects and enhanced thermal stability. Antiviral assays against SARS-CoV-2 demonstrated significant viral inhibition for HTCC6 and Ag/Cs at non-cytotoxic concentrations (6 mg/mL), highlighting the role of cationic charge and nanoparticle inclusion in antiviral efficacy. These findings indicate that the developed chitosan derivatives are promising candidates for sustainable functional coatings on medical devices, offering potential applications in infection prevention. Full article

Background/Objectives: Carbon dots (CDs) are promising antimicrobial nanomaterials owing to their biocompatibility, environmental friendliness, and tunable surface chemistry. This study aimed to synthesize nitrogen-doped CDs (AS-CDs) and develop a light-responsive antibacterial system through conjugation with chlorin e6 (Ce6). Methods: AS-CDs were synthesized by a microwave-assisted method using L-ascorbic acid and spermidine, followed by conjugation with Ce6. The materials were characterized by transmission electron microscopy, zeta potential analysis, and spectroscopic methods, and their antibacterial activity was evaluated against Escherichia coli, Staphylococcus aureus, and methicillin-resistant S. aureus (MRSA) under both dark and visible-light conditions. Cytotoxicity was assessed using HaCaT cells. Results: The AS-CDs exhibited a uniform nanoscale morphology with an average diameter of 6.3 nm and a positive surface charge of +15.6 mV, together with intrinsic broad-spectrum antibacterial activity. Ce6 conjugation further enhanced antibacterial efficacy under light irradiation, with the CDs-Ce6 conjugate achieving complete eradication of S. aureus and MRSA and marked inhibition of E. coli at 2.5 μg/mL. Cytotoxicity studies demonstrated low toxicity in HaCaT cells within the effective antibacterial concentration range. Conclusions: These findings highlight the potential of microwave-synthesized, photosensitizer-conjugated CDs as next-generation antimicrobial agents. This platform offers a cost-effective, sustainable, eco-friendly, and efficient platform for combating bacterial infections, with broader potential in pharmaceutical and biomedical applications. Full article

In this study, a hydrogel was developed based on a chondroitin sulfate–iron complex (CSFe) incorporated into a sodium alginate matrix. The CSFe complex was first prepared through the interaction of chondroitin sulfate (CS) with Fe³⁺ ions, achieving an iron content of 2.06%. Structural characterization confirmed that Fe³⁺ coordinated with the carboxyl, sulfate, and N-acetyl groups of CS, resulting in increased molecular weight and altered physicochemical properties. The CSFe complex exhibited significant antibacterial activity against Escherichia coli and Staphylococcus aureus (S. aureus), and was further incorporated into a sodium alginate matrix to form an injectable hydrogel with favorable physicochemical properties such as spreadability, shear-thinning behavior, and a compact porous microstructure. In a mouse model of S. aureus-infected wounds, the CSFe hydrogel significantly accelerated wound closure, reduced the levels of pro-inflammatory cytokines (TNF-α and IL-6), and increased the anti-inflammatory cytokine IL-10, indicating potent anti-infective and immunomodulatory functions. Overall, this work presents a multifunctional CSFe-incorporated hydrogel system that integrates antibacterial, anti-inflammatory, and tissue-regenerative properties, offering a promising strategy for infected wound healing and highlighting the potential of trivalent iron–polysaccharide coordination complexes in the development of advanced biomedical materials. Full article

Photothermal therapy (PTT) has emerged as a promising medical strategy for controlled and targeted drug delivery, due to its ability to trigger rapid release while minimizing damage to surrounding environments. Among different near-infrared (NIR)-responsive nanomaterials, carbon materials are of particular interest due to their multifunctional properties, with graphene oxide (GO) being a powerful photothermal therapy agent that can accelerate stimuli-responsive drug release. Herein, novel stimuli-responsive hydrogels based on polyvinyl alcohol (PVA), gelatin (Gel) and GO, loaded with natural quercetin (Q) were developed and evaluated for their physico-chemical properties, antibacterial and antifungal activities, photothermal Q release, and cellular metabolic activity. Upon NIR laser irradiation, after 10 min, Q was released twice as fast compared to conventional drug release without stimulation. The rapid release of Q by applying light radiation highlights the suitability of these hydrogels for controlled drug delivery applications. The PVA:Gel:GO/Q-hydrogels exhibited strong antimicrobial and antifungal performance (≥90% microbial reduction at higher GO concentrations). Furthermore, a significant reduction in S. aureus adhesion and invasion indicates the sample’s potential to mitigate bacterial infections. The PVA:Gel:GO/Q formulations exhibited high biocompatibility in Human Dermal Fibroblasts (HDF), demonstrating that Q improves the safety of PVA:Gel:GO-loaded hydrogels. These results offer promising potential for PVA:Gel:GO/Q hydrogels as advanced materials for photothermal-triggered drug delivery and antimicrobial applications. Full article

Green synthesis is an eco-friendly, simple, and cost-effective process for the synthesis of metal nanoparticles from plant extracts that are rich in bioactive compounds. In the current study, the antioxidant potential and total soluble polyphenol content (TPC) of different parts of Ligusticum mutellina (L.) Crantz were evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) assays, and the results indicated that the seed extract was the most active plant part. HPLC analysis indicated the presence of phenolic compounds such as gallic acid, protocatechuic acid, and catechin, which may contribute to the reduction and stabilization of AgNPs. Silver nanoparticles (AgNPs) were synthesized from the aqueous seed extract of L. mutellina. The formation of nanoparticles was confirmed by UV–Vis spectroscopy, FT-IR analysis, powder X-ray diffraction (PXRD), and transmission electron microscopy (TEM). The UV–Vis spectrum indicated a surface plasmon resonance peak at around 411 nm, and PXRD analysis indicated an average crystallite size of around 13 nm. TEM analysis revealed predominantly spherical nanoparticles with an average size of 25.36 ± 10.76 nm. The synthesized AgNPs exhibited strong antibacterial activity against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Overall, the results demonstrate that L. mutellina seed extract represents an effective natural source of reducing and stabilizing agents for green nanoparticle synthesis and highlight the potential of the obtained AgNPs as environmentally friendly antimicrobial materials. Full article

Secondary caries and biofilm accumulation remain major causes of failure in provisional crowns and restorations, highlighting the need for multifunctional resin coatings with antibacterial and remineralizing capabilities. This study aimed to develop a novel bioactive and antibacterial resin-based surface coating incorporating 10% dimethylaminododecyl methacrylate (DMADDM), 20% nanoparticles of amorphous calcium phosphate (NACP), and/or 20% calcium fluoride nanoparticles (nCaF₂) within a urethane dimethacrylate/triethylene glycol divinylbenzyl ether (UDMA/TEG-DVBE) matrix. Coatings were evaluated for degree of conversion (DC), flow, shear bond strength, brushing wear resistance (10,000 cycles), and calcium (Ca), phosphate (PO₄), and fluoride (F) ion release up to 70 days. All groups achieved clinically acceptable polymerization, with the lowest DC at 50%. NACP-containing coatings significantly increased shear bond strength to 18.3 ± 2.8 MPa, representing a ~170% increase compared with the experimental control (6.8 ± 2.1 MPa) and exceeding the ISO 10477 minimum threshold of 5 MPa. After brushing simulation, experimental coatings demonstrated low wear depth (0.93–1.19 µm), which was ~40% lower than the commercial control (1.85 ± 0.40 µm). Sustained ion release was achieved for 70 days, with 20% NACP-formula releasing 1.22 mmol/L Ca and 0.90 mmol/L PO₄, while the dual NACP–nCaF₂ formulation provided simultaneous Ca (0.62 mmol/L) and F (0.33 mmol/L) release. The developed coatings demonstrated promising physicochemical properties, bonding performance, wear resistance, and sustained remineralizing ion release, supporting their potential application as therapeutic surface coatings for provisional restorations. Full article