Search Results (3,905)

In the medical field, magnesium (Mg) alloys have been widely used due to their excellent antibacterial properties and biodegradability. However, in the marine environment, the antibacterial effect may be greatly attenuated, and consequently, microorganisms in the ocean are likely to adhere to the surface of Mg alloys, resulting in biocorrosion damage, which is really troublesome in the maritime industry and can even be disastrous to the navy. Currently, there is a lack of research on the biocorrosion of Mg alloys that may find important applications in marine engineering. In this paper, the biocorrosion mechanism of the Mg alloy Mg-3Nd-2Gd-Zn-Zr caused by Chlorella vulgaris (C. vulgaris), a typical marine microalga, was studied. The results showed that the biomineralization process in the artificial seawater containing a low concentration of C. vulgaris cells was accelerated compared with that in the abiotic artificial seawater, leading to the deposition of CaCO₃ on the surface to inhibit the localized corrosion of the Mg alloy, whereas a high concentration of C. vulgaris cells produced a high content of organic acids at some sites through photosynthesis to significantly accelerate the surface film rupture at some sites and severe localized corrosion there, but meanwhile, it resulted in the formation of a more protective biomineralized film in the other areas to greatly alleviate the corrosion. The contradictory biocorrosion behaviors on the Mg-3Nd-2Gd-Zn-Zr alloy induced by C. vulgaris were finally explained by a mechanism proposed in the paper. Full article

The increasing prevalence of antibiotic resistance and the limited availability of antiviral therapeutics for pathogens such as human respiratory syncytial virus (hRSV) underscore the need for novel, plant-derived antimicrobial substances. In this study, we evaluated the antiproliferative, antibacterial, and antiviral activities of aqueous leaf extracts from two plants commonly found in North America, Osage orange (M. pomifera) and spearmint (M. spicata). Both extracts exhibited no significant cytotoxic or morphologic impact on HEp-2 human cancer cells up to 25 mg/mL. However, both extracts demonstrated strong dose-dependent antibacterial activity, significantly inhibiting replication of E. coli and S. aureus at concentrations ≥ 1 mg/mL. Antiviral assays revealed that both extracts inhibited hRSV infectivity, with spearmint extract showing higher potency (EC₅₀ = 1.01 mg/mL) compared to Osage orange (EC₅₀ = 3.85 mg/mL). Gas chromatography–mass spectrometry (GC-MS) identified three major extract constituents: 3-hydroxybenzyl alcohol, 4-hydroxybenzyl alcohol (Osage orange), and R-(-)-carvone (spearmint). Among these, only carvone significantly inhibited hRSV in vitro, suggesting its key role in spearmint’s antiviral activity. These findings highlight the therapeutic potential of Osage orange and spearmint leaf extracts, particularly as sources of water-soluble compounds with antimicrobial properties, and support further investigation into their mechanisms of action and broader clinical relevance. Full article

This study aimed to develop an innovative resin composite with anti-biofouling properties, tailored to prosthesis fabrication in dentistry using a digital light processing (DLP) 3D-printing technique. The resin composite was formulated using a blend of dental monomers, with the integration of 2-methacryloyloxylethyl phosphorylcholine (MPC) with anti-biofouling behavior and γ-MPS-treated silica-zirconia powder for simultaneous mechanical reinforcement. The overall characterization of the resin composite was carried out using various contents of MPC incorporated into the resin (0–7 wt%) for examining the rheological behavior, photopolymerization, flexural strength/modulus, microstructure and anti-biofouling efficiency. The resin composite demonstrated a significant reduction in bacterial adhesion (97.4% for E. coli and 86.5% for S. aureus) and protein adsorption (reduced OD value from 1.3 ± 0.4 to 0.8 ± 0.2) with 7 wt% of MPC incorporation, without interfering with photopolymerization to demonstrate potential suitability for 3D printing without issues (p < 0.01, and p < 0.05, respectively). The incorporation and optimization of γ-MPS-treated silica-zirconia powder (10–40 vol%) enhanced mechanical properties, leading to a reasonable flexural strength (103.4 ± 6.1 MPa) and a flexural modulus (4.3 ± 0.4 GPa) at 30 vol% (n = 6). However, a further increase to 40 vol% resulted in a reduction in flexural strength and modulus; nevertheless, the results were above ISO 10477 standards for dental materials. Full article

Background/Objectives: The functionalization of various forms of graphene, such as graphene nanoplatelets, graphene oxide, and reduced graphene oxide, in biomaterials is a promising strategy in dentistry, particularly regarding their antimicrobial potential. However, conclusive studies on the toxicity and biocompatibility of graphene-based materials remain limited, and standardized guidelines for their production, handling, and dental applications are still lacking. This scoping review aims to map the available studies on various types of graphene, synthesize evidence on their antimicrobial effectiveness, and describe the main biological responses when functionalized in dental biomaterials. Methods: An electronic search was conducted in the Clarivate, PubMed, and Scopus databases using the descriptors as follows: ‘graphene’ AND ‘antimicrobial effect’ AND ‘bactericidal effect’ AND (‘graphene oxide’ OR ‘dental biofilm’ OR ‘antibacterial properties’ OR ‘dental materials’). Article screening and eligibility assessment were performed based on predefined inclusion and exclusion criteria, following the PRISMA-ScR guidelines. Results: The search identified 793 articles. After removing duplicates, applying the eligibility criteria, and performing a full-text analysis of 64 articles, 21 studies were included in the review. Graphene oxide, particularly at low concentrations, was the most commonly studied graphene variant, demonstrating significant antimicrobial efficacy against S. mutans, S. faecalis, E. coli, P. aeruginosa, and C. albicans. Both mechanical and chemical mechanisms have been linked to the biological responses of graphene-doped biomaterials. The biocompatibility and cytotoxicity of these compounds remain controversial, with some studies reporting favorable outcomes, while others raise significant concerns. Conclusions: Graphene shows great promise as an antimicrobial agent in dental biomaterials. Despite encouraging results, more in vitro and in vivo studies are needed to better understand its biocompatibility and cytotoxicity in dental applications. Additionally, standardized production protocols, clearly defined clinical applications in dentistry, and regulatory guidelines from the World Health Organization concerning handling procedures and occupational risks remain necessary. Full article

Background: The aim of this review is to summarize and evaluate the properties of antibacterial polysaccharides for application in dental implantology to identify knowledge gaps and provide new research ideas. Methods: The electronic databases PubMed, Medline, ProQuest, and Google Scholar were used to search for peer-reviewed scientific publications published between 2018 and 2025 that provide insights to answer research questions on the role of antibacterial polysaccharides in combating pathogens in dental implantology without triggering immune reactions and inflammation. Further research questions relate to the efficacy against various dental pathogens and the understanding of the antibacterial mechanism, which may enable the development of functionalized polysaccharides with long-term antibacterial activity. Results: Biomedical implants have revolutionized medicine but also increased the risk of infections. Implant infections are a major problem in implantology and lead to implant failure and replacement. An antibacterial coating could be an excellent strategy to extend the lifespan of implants and improve the quality of the patient’s life. Bacterial resistance to antibiotics poses significant challenges for researchers, forcing them to search for new ways to prevent bacterial infections in implantology. Antibacterial natural polymers have recently received considerable research attention due to their long-term antibacterial activity. Polysaccharides from marine sources, such as chitosan and alginate, or pectin, xanthan, etc., from various plants, appear to be promising biopolymers for such applications in implantology due to their antibacterial activity, biocompatibility, and osteogenic properties. The antibacterial activity of these natural biopolymers depends on their chemical and physical properties. Nanopolysaccharides exhibit higher antibacterial activity than conventional polysaccharides, but their toxicity to human cells must be considered. Their antibacterial activity is based on the disruption of bacterial DNA or RNA synthesis, increased cell wall permeability, membrane disruption, and cytoplasmic leakage. Conclusions: Polysaccharides are a class of natural polymers with a broad spectrum of biological activities. They exhibit antioxidant, immunomodulatory, anticoagulant, anticancer, anti-inflammatory, antibacterial, and antiviral activity. Furthermore, polysaccharides are non-cytotoxic and exhibit good biocompatibility with osteogenic cells. Bactericidal polysaccharides are attractive new antibacterial materials against implant infections and open up new perspectives in implantology. Full article

Palindromic antimicrobial peptides (PAMs) constitute versatile scaffolds for the design and optimization of anticancer agents with applications in therapy, diagnosis, and/or monitoring. In the present study, fluorolabeled peptides derived from the palindromic sequence RWQWRWQWR containing fluorescent probes, such as 2-Aminobenzoyl, 5(6)-Carboxyfluorescein, and Rhodamine B, were obtained. RP-HPLC analysis revealed that the palindromic peptide conjugated to Rhodamine B (RhB-RWQWRWQWR) exhibited the presence of isomers, likely corresponding to the open-ring and spiro-lactam forms of the fluorescent probe. This equilibrium is dependent on the peptide sequence, as the RP-HPLC analysis of dimeric peptide (RhB-RRWQWR-hF-KKLG)₂K-Ahx did not reveal the presence of isomers. The antibacterial activity of the fluorescent peptides depends on the probe attached to the sequence and the bacterial strain tested. Notably, some fluorescent peptides showed activity against reference strains as well as sensitive, resistant, and multidrug-resistant clinical isolates of E. coli, S. aureus, and E. faecalis. Fluorolabeled peptides 1-Abz (MIC = 62 µM), RhB-1 (MIC = 62 µM), and Abz-1 (MIC = 31 µM) exhibited significant activity against clinical isolates of E. coli, S. aureus, and E. faecalis, respectively. The RhB-1 (IC₅₀ = 61 µM), Abz-1 (IC₅₀ = 87 µM), and RhB-2 (IC₅₀ = 35 µM) peptides exhibited a rapid, significant, and concentration-dependent cytotoxic effect on HeLa cells, accompanied by morphological changes characteristic of apoptosis. RhB-1 (IC₅₀ = 18 µM) peptide also exhibited significant cytotoxic activity against breast cancer cells MCF-7. These conjugates remain valuable for elucidating the possible mechanisms of action of these novel anticancer peptides. Rhodamine-labeled peptides displayed cytotoxicity comparable to that of their unlabeled analogues, suggesting that cellular internalization constitutes a critical early step in their mechanism of action. These findings suggest that cell death induced by both unlabeled and fluorolabeled peptides proceeds predominantly via apoptosis and is likely contingent upon peptide internalization. Functionalization at the N-terminal end of the palindromic sequence can be evaluated to develop systems for transporting non-protein molecules into cancer cells. Full article

Nosocomial infections caused by ESKAPE pathogens represent a significant burden to global health. These pathogens may exhibit multidrug resistance (MDR) mechanisms, of which mechanisms such as efflux pumps and biofilm formation are gaining significant importance. Multidrug resistance mechanisms in ESKAPE pathogens have led to an increase in the effective costs in health care and a higher risk of mortality in hospitalized patients. These pathogens utilize antimicrobial efflux pump mechanisms and bacterial biofilm-forming capabilities to escape the bactericidal action of antimicrobials. ESKAPE bacteria forming colonies demonstrate increased expression of efflux pump-encoding genes. Efflux pumps not only expel antimicrobial agents but also contribute to biofilm formation by bacteria through (1) transport of molecules and transcription factors involved in biofilm quorum sensing, (2) bacterial fimbriae structure transport for biofilm adhesion to surfaces, and (3) regulation of a transmembrane gradient to survive the difficult conditions of biofilm microenvironments. The synergistic role of these mechanisms complicates treatment outcomes. Given the mechanistic link between biofilms and efflux pumps, therapeutic strategies should focus on targeting anti-biofilm mechanisms alongside efflux pump inactivation with efflux pump inhibitors. This review explores the molecular interplay between efflux pumps and biofilm formation, emphasizing potential therapeutic strategies such as efflux pump inhibitors (EPIs) and biofilm-targeting agents. Full article

Background: Antibacterial resistance (ABR) poses a major challenge to global health, with methicillin-resistant Staphylococcus aureus (MRSA) being one of the prominent multidrug-resistant strains. MRSA has developed resistance through the expression of Penicillin-Binding Protein 2a (PBP2a), a key transpeptidase enzyme involved in bacterial cell wall biosynthesis. Objectives: The objective was to design and characterize a novel small-molecule inhibitor targeting PBP2a as a strategy to combat MRSA. Methods: We synthesized a new indole triazole conjugate (ITC) using eco-friendly and click chemistry approaches. In vitro antibacterial tests were performed against a panel of strains to evaluate the ITC antibacterial potential. Further, a series of in silico evaluations like molecular docking, MD simulations, free energy landscape (FEL), and principal component analysis (PCA) using the crystal structure of PBP2a (PDB ID: 4CJN), in order to predict the mechanism of action, binding mode, structural stability, and energetic profile of the 4CJN-ITC complex. Results: The compound ITC exhibited noteworthy antibacterial activity, which effectively inhibited the selected strains. Binding score and energy calculations demonstrated high affinity of ITC for the allosteric site of PBP2a and significant interactions responsible for complex stability during MD simulations. Further, FEL and PCA provided insights into the conformational behavior of ITC. These results gave the structural clues for the inhibitory action of ITC on the PBP2a. Conclusions: The integrated in vitro and in silico studies corroborate the potential of ITC as a promising developmental lead targeting PBP2a in MRSA. This study demonstrates the potential usage of rational drug design approaches in addressing therapeutic needs related to ABR. Full article

Titanium alloys such as Ti-6Al-4V are widely used in biomedical implants due to their excellent mechanical properties and biocompatibility, but their bioinert nature limits osseointegration and antibacterial performance. This study proposes a multifunctional surface coating system integrating a thermally oxidized TiO₂ interlayer with a hydroxyapatite (HAp) top layer synthesized via a green route using Hylocereus undatus extract. The HAp was deposited by electrophoretic deposition (EPD), enabling continuous coverage and strong adhesion to the pre-treated Ti-6Al-4V substrate. Structural, morphological, chemical, and electrical characterizations were performed using XRD, SEM, EDS, Raman spectroscopy, and impedance spectroscopy. Bioactivity was assessed through apatite formation in simulated body fluid (SBF), while antibacterial properties were evaluated against Staphylococcus aureus. The results demonstrated successful formation of crystalline TiO₂ (rutile phase) and calcium-rich HAp with good surface coverage. The HAp-coated surfaces exhibited significantly enhanced bioactivity and strong antibacterial performance, likely due to the combined effects of surface roughness and the bioactive compounds present in the plant extract. This study highlights the potential of eco-friendly, bio-inspired surface engineering to improve the biological performance of titanium-based implants. Full article

This study investigated the influence of curing temperature and time on both the mechanical properties and cytotoxicity of stereolithographic polymethyl methacrylate (PMMA) resin. After printing using stereolithographic equipment, the resin was cured at 45 °C, 60 °C, and 75 °C for up to 120 min. Our results reveal that the mechanical properties achieved a peak after approximately 30 min of curing at the two highest temperatures, followed by a subsequent decrease, while curing at 45 °C resulted in a constant increase in mechanical properties up to 120 min. Testing with S. epidermidis and E. coli exhibited a bland antibacterial effect, with the number of living bacteria increasing with both the time and temperature of curing. To assess potential cytotoxicity, the materials were also tested with human fibroblasts, and the trends observed were similar to what was previously seen for both bacteria strains. Interestingly, an association was observed between the intensity ratio of two Raman bands (around 2920 and 2945 cm⁻¹), indicative of long-PMMA-chain formation and cytotoxicity. This finding suggests that Raman spectroscopy has the potential to serve as a viable method for estimating the cytotoxicity of 3D printed PMMA objects. Full article

Allyl isothiocyanate (AITC) is a naturally occurring, pungent compound abundant in cruciferous vegetables and functions as a repellent for various organisms. The antibacterial effect of AITC against various bacteria has been reported, but there are no reports on the effect on Streptococcus mutans, a major bacterium contributing to dental caries. In this study, we investigated the inhibitory effect and mechanism of AITC on the survival and growth of S. mutans. AITC showed an antibacterial effect in a time- and concentration-dependent manner. In addition, bacterial growth was delayed in the presence of AITC, and there were almost no bacteria in the presence of 0.1% AITC. In a biofilm assay, the amount of biofilm formation with 0.1% AITC was significantly decreased compared to the control. RNA sequencing analysis showed that the expression of 39 genes (27 up-regulation and 12 down-regulation) and 38 genes (24 up-regulation and 14 down-regulation) of S. mutans was changed during the survival and the growth, respectively, in the presence of AITC compared with the absence of AITC. Protein–protein interaction analysis revealed that AITC mainly interacted with genes of unknown function in S. mutans. These results suggest that AITC may inhibit cariogenicity of S. mutans through a novel mechanism. Full article

Developing multifunctional wound dressings with excellent mechanical properties, strong tissue adhesion, and efficient antibacterial activity is crucial for promoting wound healing. This study prepared a novel nanocomposite hydrogel dressing based on sodium alginate-polyacrylic acid dual crosslinking networks, incorporating tannic acid-coated cellulose nanocrystals (TA@CNC) and in-situ reduced silver nanoparticles for multifunctional enhancement. The rigid CNC framework significantly improved mechanical properties (elastic modulus of 146 kPa at 1 wt%), while TA catechol groups provided excellent adhesion (36.4 kPa to pigskin, 122% improvement over pure system) through dynamic hydrogen bonding and coordination interactions. TA served as a green reducing agent for uniform AgNPs loading, with CNC negative charges preventing particle aggregation. Antibacterial studies revealed synergistic effects between TA-induced membrane disruption and Ag⁺-triggered reactive oxygen species generation, achieving >99.5% inhibition against Staphylococcus aureus and Escherichia coli. The TA@CNC-regulated porous structure balanced swelling performance and water vapor transmission, facilitating wound exudate management and moist healing. This composite hydrogel successfully integrates mechanical toughness, tissue adhesion, antibacterial activity, and biocompatibility, providing a novel strategy for advanced wound dressing development. Full article

In recent years, active packaging has become a focal point of research and development in the food industry, driven by increasing consumer demand for safe, high-quality, and sustainable food products. In this work, solvent casting processed an active antibacterial multicomponent film based on hydroxypropyl methylcellulose incorporated with ferulic acid and chitin nanofibers. The influences of ferulic acid and different content of chitin nanofibers on the structure, thermal, mechanical, and water vapor stability and antioxidant and antibacterial efficiency of films were studied. It was shown that the inclusion of only ferulic acid did not significantly influence the mechanical, water vapor, and thermal stability of films. In addition, films containing only ferulic acid did not display antibacterial activity. The optimal concentration of chitin nanofibers in hydroxypropyl methylcellulose–ferulic acid films was 5 wt%, providing a tensile strength of 15 MPa, plasticity of 52%, and water vapor permeability of 0.94 × 10⁻⁹ g/m s Pa. With further increase of chitin nanofibers content, films with layered and discontinuous phases are obtained, which negatively influence tensile strength and water vapor permeability. Moreover, only films containing both ferulic acid and chitin nanofibers demonstrated antibacterial activity toward E. coli and S. aureus, suggesting that the presence of fibers allows easier release of ferulic acid from the matrix. These results imply that the investigated three-component systems have potential applicability as sustainable active food packaging materials. Full article

Cinnamic acid, an organic acid naturally occurring in plants of the Cinnamomum genus, has been highly valued for its medicinal properties in numerous ancient Chinese texts. This article reviews the chemical composition, pharmacological effects, and various applications of cinnamic acid and its derivatives reported in publications from 2016 to 2025, and anticipates their potential in medical and industrial fields. This review evaluates studies in major scientific databases, including Web of Science, PubMed, and ScienceDirect, to ensure a comprehensive analysis of the therapeutic potential of cinnamic acid. Through systematic integration of existing knowledge, it has been revealed that cinnamic acid has a wide range of pharmacological activities, including anti-tumor, antibacterial, anti-inflammatory, antidepressant and hypoglycemic effects. Additionally, it has been shown to be effective against a variety of pathogens such as Staphylococcus aureus, Pseudomonas aeruginosa, and foodborne Pseudomonas. Cinnamic acid acts by disrupting cell membranes, inhibiting ATPase activity, and preventing biofilm formation, thereby demonstrating its ability to act as a natural antimicrobial agent. Its anti-inflammatory properties are demonstrated by improving oxidative stress and reducing inflammatory cell infiltration. Furthermore, cinnamic acid enhances metabolic health by improving glucose uptake and insulin sensitivity, showing promising results in improving metabolic health in patients with diabetes and its complications. This systematic approach highlights the need for further investigation of the mechanisms and safety of cinnamic acid to substantiate its use as a basis for new drug development. Particularly in the context of increasing antibiotic resistance and the search for sustainable, effective medical treatments, the study of cinnamic acid is notably significant and innovative. Full article

Methicillin-resistant Staphylococcus aureus (MRSA), a multidrug-resistant pathogen, poses a significant threat to global healthcare. This review evaluates the potential of marine algal metabolites as novel antibacterial agents against MRSA. We explore the clinical importance of S. aureus, the emergence of MRSA as a “superbug”, and its resistance mechanisms, including target modification, drug inactivation, efflux pumps, biofilm formation, and quorum sensing. The limitations of conventional antibiotics (e.g., β-lactams, vancomycin, macrolides) are discussed, alongside the promise of algal-derived compounds such as fatty acids, pigments, polysaccharides, terpenoids, and phenolic compounds. These metabolites exhibit potent anti-MRSA activity by disrupting cell division (via FtsZ inhibition), destabilizing membranes, and inhibiting protein synthesis and metabolic pathways, effectively countering multiple resistance mechanisms. Leveraging advances in algal biotechnology, this review highlights the untapped potential of marine algae to drive innovative, sustainable therapeutic strategies against antibiotic resistance. Full article