Search Results (1,621)

Background/Objective: Staphylococcus aureus (S. aureus) is a clinically significant pathogenic bacterium. Daptomycin (DAP) is a cyclic lipopeptide antibiotic used to treat infections caused by multidrug-resistant Gram-positive bacteria, including S. aureus. However, DAP currently faces clinical limitations due to its short half-life, toxic side effects, and increasingly severe drug resistance issues. This study aimed to develop a biomimetic nano-drug delivery system to enhance targeting ability, prolong blood circulation, and mitigate resistance of DAP. Methods: DAP-loaded chitosan nanocomposite particles (DAP-CS) were prepared by electrostatic self-assembly. Macrophage membrane vesicles (MM) were prepared by fusion of M1-type macrophage membranes with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). A biomimetic nano-drug delivery system (DAP-CS@MM) was constructed by the coextrusion process of DAP-CS and MM. Key physicochemical parameters, including particle diameter, zeta potential, encapsulation efficiency, and membrane protein retention, were systematically characterized. In vitro immune escape studies and in vivo zebrafish infection models were employed to assess the ability of immune escape and antibacterial performance, respectively. Results: The particle size of DAP-CS@MM was 110.9 ± 13.72 nm, with zeta potential +11.90 ± 1.90 mV, and encapsulation efficiency 70.43 ± 1.29%. DAP-CS@MM retained macrophage membrane proteins, including functional TLR2 receptors. In vitro immune escape assays, DAP-CS@MM demonstrated significantly enhanced immune escape compared with DAP-CS (p < 0.05). In the zebrafish infection model, DAP-CS@MM showed superior antibacterial efficacy over both DAP and DAP-CS (p < 0.05). Conclusions: The DAP-CS@MM biomimetic nano-drug delivery system exhibits excellent immune evasion and antibacterial performance, offering a novel strategy to overcome the clinical limitations of DAP. 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

The rise in multidrug-resistant bacterial strains and persistent infections such as Lyme disease caused by Borrelia burgdorferi highlights the need for novel antimicrobial agents. The present study explores the antioxidant, antibacterial, and cytotoxic properties of extracts from submerged mycelial biomass of Fomitopsis pinicola, cultivated in synthetic and lignocellulosic media. Four extracts were obtained using hot water and 80% ethanol. The provided analysis of extracts confirmed the presence of various bioactive compounds, including flavonoids, alkaloids, and polyphenols. All extracts showed dose-dependent antioxidant activity (IC₅₀: 1.9–6.7 mg/mL). Antibacterial tests revealed that Klebsiella pneumoniae was most sensitive, with the L2 extract producing the largest inhibition zone (15.33 ± 0.47 mm), while the strongest bactericidal effect was observed against Acinetobacter baumannii (MBC as low as 0.5 mg/mL for L1). Notably, all extracts significantly reduced the viability of stationary-phase B. burgdorferi cells, with L2 reducing viability to 42 ± 2% at 5 mg/mL, and decreased biofilm mass, especially with S2. Cytotoxicity assays showed minimal effects on NIH 3T3 cells, with slight toxicity in HEK 293 cells for S2 and L1. These results suggest that F. pinicola extracts, particularly ethanolic L2 and S2, may offer promising natural antimicrobial and antioxidant agents for managing resistant infections. Full article

Over the last few decades, the growing demand for sustainable resources has made biopolymers increasingly popular, as they offer an eco-friendly alternative to conventional synthetic polymers, which are often associated with environmental issues such as the formation of microplastics and toxic substances. Functionalization of biomaterials involves modifying their physical, chemical, or biological properties to improve their performance for specific applications. Cellulose and bacterial cellulose are biopolymers of interest, due to the plethora of hydroxyl groups, their high surface area, and high porosity, which makes them ideal candidates for several applications. However, there are applications, which require precise control of their wetting properties. In this review, we present the most effective fabrication methods for modifying both the morphology and the chemical properties of cellulose and bacterial cellulose, towards the realization of superhydrophobic bacterial cellulose films and surfaces. Such materials can find a wide variety of applications, yet in this review we target and discuss applications deriving from the wettability control, such as antibacterial surfaces, wound healing films, and separation media. Full article

The integration of nanotechnology and green synthesis strategies provides innovative solutions in biomedicine. This study focuses on the biofabrication of silver nanoparticles (AgNPs) using Corynespora smithii, an endophytic fungus isolated from Bergenia ciliata. The eco-friendly synthesis process employed fungal extracts as reducing and stabilizing agents thereby minimizing the need for hazardous chemicals. The AgNPs demonstrated strong potent biological activities, showcasing significant antioxidant, antibacterial, and anticancer properties. The antibacterial efficacy was demonstrated against various Gram-positive and Gram-negative bacteria, while cytotoxicity on the A549 lung cancer cell line revealed an IC₅₀ value of 10.46 µg/mL. A molecular docking analysis revealed interactions between the major bioactive compound, dimethylsulfoxonium formylmethylide, and the pathogenic proteins, Staphylococcus aureus and Salmonella typhi, displaying moderate binding affinities. Furthermore, the ADME analysis of dimethylsulfoxonium formylmethylide indicated favourable pharmacokinetic properties, including high gastrointestinal absorption, minimal lipophilicity, and low potential for drug–drug interactions, making it a promising candidate for oral drug formulations. These findings further support the compound’s suitability for biomedical applications. This research emphasizes the potential of C. smithii as a sustainable source for synthesizing bioactive nanoparticles, paving the way for their application in developing novel therapeutic agents. This study highlights the significance of harnessing endophytic fungi from medicinal plants for sustainable nanotechnology advancements. Full article

In the present study, for the first time, a biodegradable and non-toxic polyphosphoramidate glycohydrogel (PPAGHGel) was prepared by crosslinking a polyphosphoramidate glycoconjugate (PPAG) with hexamethylene diisocyanate (HMDI) under mild conditions. Poly(oxyethylene H-phosphonate) (POEHP) was used as a precursor and was converted into PPAG via the Staudinger reaction with glucose-containing azide (2-p-azidobenzamide-2-deoxy-1,3,4,6-tetra-O-trimethylsilyl-α-D-glucopyranose). Then, crosslinking of PPAG was performed to yield PPAGHGel, which was thoroughly characterized. The gel showed a gel fraction of 83%, a swelling degree of 1426 ± 98%, and G″ = 1560 ± 65 Pa. The gel was fully degraded by alkaline phosphatase (400 U/L, pH 9) in 19 days, while hydrolytically, up to 52% degradation was observed under similar conditions. Multivalent studies of the obtained hydrogel with lectin–Concanavalin A were performed. PPAGHGel binds 92% of Concanavalin A within 24 h and the complex remains stable until the amount of glucose reaches 0.3 mM. PPAGHGel acts as a stabilizer for silver nanoparticles (12 nm). SEM shows pores measuring 10 µm (surface) and 0.1 mm (interior) with capillary channels, confirming the gel’s suitability for biosensors, drug delivery, or wound dressings. The cytotoxic (IC50) and cell-adhesive properties of the obtained hydrogel were investigated on human cell lines (HeLa). Antibacterial activity tests were also performed with gel containing silver nanoparticles against skin-associated pathogenic bacteria. The results show that PPAGHGel possesses excellent biocompatibility, non-adhesive properties and antibacterial activity. Full article

The marine seaweed Undaria pinnatifida belongs to the large group of brown macroalgae (Ochrophyta) and is valued both as a nutritious food and a source of pharmaceutical compounds. It has been widely consumed in East Asia as part of the traditional diet and is generally regarded as a “healthy longevity food.” Consequently, it represents one of the most promising natural sources of biomedicinal and bioactive products. This review aims to synthesize current scientific evidence on the pharmacologically active compounds of U. pinnatifida, emphasizing their mechanisms of action and therapeutic potential in neurodegenerative and chronic diseases. This narrative review is based on a comprehensive literature search of peer-reviewed articles from scientific databases, focusing on studies addressing the pharmacological properties of U. pinnatifida and its major bioactive constituents. Recent research highlights that compounds such as fucoxanthin (a carotenoid), fucosterol (a sterol), fucoidan (a polysaccharide), alginate, and dietary fiber found in U. pinnatifida possess significant potential for developing treatments for conditions including goitre, urinary diseases, scrofula, dropsy, stomach ailments, and hemorrhoids. Moreover, these compounds exhibit remarkable pharmacological properties, including immunomodulation, antitumor, antiviral, antioxidant, antidiabetic, anti-inflammatory, anticoagulant, antithrombotic, and antibacterial activities, all with low toxicity and minimal side effects. Additionally, U. pinnatifida shows promise in the treatment or prevention of neurodegenerative diseases such as Alzheimer’s and Parkinson’s, as well as neuropsychiatric conditions like depression, supported by its antioxidant effects against oxidative stress and neuroprotective activities. Numerous in vitro and in vivo studies have confirmed that U. pinnatifida polysaccharides (UPPs), particularly fucoidans, exhibit significant biological activities. Thus, accumulating evidence positions UPPs as promising therapeutic agents for a variety of diseases. Full article

Background/Objectives: The liver, the body’s primary detoxifying organ, is often affected by various inflammatory diseases, including hepatitis, cirrhosis, and non-alcoholic fatty liver disease (NAFLD), many of which can be exacerbated by secondary infections such as spontaneous bacterial peritonitis, bacteremia, and sepsis—particularly in patients with advanced liver dysfunction. The global rise in these conditions underscores the need for effective interventions. Natural products have attracted attention for their potential to support liver health, particularly through synergistic combinations of plant extracts. Epavin, a dietary supplement from Erbenobili S.r.l., formulated with plant extracts like Taraxacum officinale (L.), Silybum marianum (L.) Gaertn., and Cynara scolymus (L.), known for their liver-supporting properties, has been proposed as adjuvant for liver functions. The aim of this work was to evaluate of Epavin’s antioxidant, anti-inflammatory, and protective effects against heavy metal-induced toxicity. In addition, the antibacterial effect of Epavin against a panel of bacterial strains responsible for infections associated with liver injuries has been evaluated. Methods: The protection against oxidative stress induced by H₂O₂ was evaluated in HepG2 and BALB/3T3 cells using the dichlorofluorescein diacetate (DCFH-DA) assay. Its anti-inflammatory activity was investigated by measuring the reduction in nitric oxide (NO) production in LPS-stimulated RAW 264.7 macrophages using the Griess assay. Additionally, the cytoprotecting of Epavin against heavy metal-induced toxicity and oxidative stress were evaluated in HepG2 cells using the [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide] (MTT) and DCFH-DA assays. The antibacterial activity of Epavin was assessed by determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) against Gram-positive (Enterococcus faecalis ATCC 29212, and BS, Staphylococcus aureus 25923, 29213, 43300, and BS) and Gram-negative (Escherichia coli 25922, and BS, Klebsiella pneumoniae 13883, 70063, and BS) bacterial strains using the microdilution method in broth, following the Clinical and Laboratory Standards Institute’s (CLSI) guidelines. Results: Epavin effectively reduced oxidative stress in HepG2 and BALB/3T3 cells and decreased NO production in LPS-stimulated RAW 264.7 macrophages. Moreover, Epavin demonstrated a protective effect against heavy metal-induced toxicity and oxidative damage in HepG2 cells. Finally, it exhibited significant antibacterial activity against both Gram-positive and Gram-negative bacterial strains, with MIC values ranging from 1.5 to 6.0 mg/mL. Conclusions: The interesting results obtained suggest that Epavin may serve as a valuable natural adjuvant for liver health by enhancing detoxification processes, reducing inflammation, and exerting antibacterial effects that could be beneficial in the context of liver-associated infections. Full article

Pasteurella multocida (Pm) is a zoonotic pathogen that poses a significant threat to animal health and causes substantial economic losses, further aggravated by rising tetracycline resistance. To restore the efficacy of tetracyclines to Pm, we evaluated the synergistic antibacterial activity of doxycycline combined with metformin, an FDA-approved antidiabetic agent. Among several non-antibiotic adjuvant candidates, metformin exhibited the most potent in vitro synergy with doxycycline, especially against capsular serogroup A strain (PmA). The combination demonstrated minimal cytotoxicity and hemolysis in both mammalian and avian cells and effectively inhibited resistance development under doxycycline pressure. At 50 mg/kg each, the combination of metformin and doxycycline significantly reduced mortality in mice and ducks acutely infected with PmA (from 100% to 60%), decreased pulmonary bacterial burdens, and alleviated tissue inflammation and damage. Mechanistic validation confirmed that metformin enhances membrane permeability in Pm without compromising membrane integrity, dissipates membrane potential, increases intracellular doxycycline accumulation, and downregulates the transcription of the tetracycline efflux gene tet(B). Morphological analyses further revealed pronounced membrane deformation and possible leakage of intracellular contents. These findings highlight metformin as a potent, low-toxicity tetracycline adjuvant with cross-species efficacy, offering a promising therapeutic approach for managing tetracycline-resistant Pm infections. Full article

This work presents the synthesis, characterization and evaluation of physicochemical and biological properties of two new aminoporphyrazine derivatives bearing magnesium(II) cations in their cores and peripheral pyrrolyl groups. The synthesis was carried out in several stages, using classical methods and the Microwave-Assisted Organic Synthesis (MAOS) approach. The obtained compounds were characterized using spectral techniques: UV-Vis spectrophotometry, mass spectrometry, ¹H and ¹³C NMR spectroscopy. The porphyrazine derivatives were tested for their electrochemical properties (CV and DPV), which revealed four redox processes, of which in compound 7 positive shifts of oxidation potentials were observed, resulting from the presence of free phenolic hydroxyl groups. In spectroelectrochemical measurements, changes in UV-Vis spectra associated with the formation of positive-charged states were noted. Photophysical studies revealed the presence of characteristic absorption Q and Soret bands, low fluorescence quantum yields and small Stokes shifts. The efficiency of singlet oxygen generation (Φ_Δ) was higher for compound 6 (up to 0.06), but compound 7, despite its lower efficiency (0.02), was distinguished by a better biological activity profile. Toxicity tests using the Aliivibrio fischeri bacteria indicated the lower toxicity of 7 compared to 6. The most promising result was the strong photodynamic activity of porphyrazine 7 against the Methicillin-resistant Stapylococcus aureus (MRSA) strain, leading to a more-than-5.6-log decrease in viable counts after the colony forming units (CFU) after light irradiation. Compound 6 did not show any significant antibacterial activity. The obtained data indicate that porphyrazine 7 is a promising candidate for applications in photodynamic therapy of bacterial infections. Full article

This study investigates the antioxidant, antimicrobial, and antitumor activities of Taraxacum officinale (Dandelion) and Artemisia annua (Sweet Wormwood) extracts, along with their role in the green synthesis of gold (AuNPs) and silver nanoparticles (AgNPs). Bioreduction was achieved using aqueous and ethanolic extracts (100 mg/mL), enabling solvent-dependent comparisons. Nanoparticles were characterized using ultraviolet–visible spectroscopy (UV–Vis), fluorescence spectroscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS), high-resolution transmission electron microscopy (HRTEM), and zeta potential analysis. Each technique revealed complementary aspects of nanoparticle morphology, size, and stability, with UV–Vis indicating aggregation states and DLS confirming solvent-related size variation even at 3–5% ethanol. Gold nanoparticles synthesized from Dandelion showed strong antibacterial activity against Staphylococcus aureus, while silver nanoparticles from both plants were effective against Escherichia coli. Cytotoxicity assays indicated that silver nanoparticles obtained from ethanolic Dandelion extract containing 3% ethanol in aqueous solution (AgNPsE_ETOH3%-D) significantly reduced LoVo (p = 4.58 × 10⁻³) and MDA-MB-231 (p = 7.20 × 10⁻⁵) cell viability, with high selectivity indices (SI), suggesting low toxicity toward normal cells. Gold nanoparticles synthesized from aqueous Dandelion extract (AuNPsEaq-D) also showed favorable SI values (2.16 for LoVo and 8.41 for MDA-MB-231). Although some formulations demonstrated lower selectivity (SI < 1.5), the findings support the therapeutic potential of these biogenic nanoparticles. Further in vivo studies and pharmacokinetic evaluations are required to validate their clinical applicability. Full article

Vitexin and isovitexin are dietary flavonoids widely distributed in food and medicinal plants. They have attracted increasing attention owing to their diverse pharmacological activities and favorable safety profiles. These compounds exhibit therapeutic potential across multiple biological systems, including the immune, nervous, respiratory, cardiovascular, and endocrine systems, through antioxidant, anti-inflammatory, anticancer, antibacterial, and neuroprotective mechanisms. Although previous reviews have addressed the pharmacological effects of vitexin and isovitexin, most are limited in scope—either focusing solely on vitexin or restricted to specific disease models such as cancer or diabetes. Moreover, some studies are outdated and do not reflect the recent advances in synthetic modification, green extraction technologies, and systems pharmacology. This review aims to provide a comprehensive evaluation of the pharmacological properties, pharmacokinetics, and clinical relevance of vitexin and isovitexin, highlighting their potential in disease prevention and treatment. A literature search was conducted using Web of Science, PubMed, and Google Scholar, with keywords including “vitexin”, “isovitexin”, “disease”, and “mechanism”. Here, we summarize the current research on the pharmacological effects of vitexin and isovitexin in metabolic disorders, inflammatory diseases, cancer, and neurodegenerative conditions, focusing on their molecular mechanisms and therapeutic targets. Furthermore, we discussed their toxicity, bioavailability, pharmacokinetics, and clinical research findings. Vitexin and isovitexin hold promise as therapeutic agents or adjuncts for multiple diseases with potential applications in modern medicine and healthcare. However, their pharmacological mechanisms, clinical efficacy, and potential synergistic effects with other therapeutic agents remain unclear. Further systematic research is needed to clarify molecular targets and optimize their therapeutic applications. Full article

To date, various species of Erigeron genus have been used both in the ethnopharmacology of numerous nations across the world and in contemporary herbal practices. The objective of this study is to revise the phytochemical data on the essential oils (EOs) of various fleabanes species and to evaluate the variability of their biological activities. Up to June 2025, this review provides an updated overview of 105 literature sources (published during last 25 years) related to 14 Erigeron sp. (native, naturalized, or invasive) which have been investigated extensively and are of the greatest significance. It summarizes the compositional variability of the EOs and their pharmacological and toxic effects, such as anti-inflammatory, anticancer, antiproliferative, skin regeneration, antioxidant, antifungal, antibacterial, insecticidal, larvicidal, repellent, and allelopathic activity. The EOs of each Erigeron species were characterized, and a chemical structure of 43 major constituents is presented herein. The most characteristic and prevalent compounds were found to be limonene, δ-3-carene, matricaria ester, lachnophyllum ester, germacrene D, β-caryophyllene, β-farnesene, α-bergamotene, allo-aromadendrene, etc., in the EOs from the E. acris, E. annuus, E. bonariensis, E. canadensis, E. floribundus E. mucronatus, and E. speciosus plants. Major constituents, such as borneol, bornyl acetate, modhephen-8-β-ol, cis-arteannuic alcohol, β-caryophyllene, and τ-cadinol, were found in the oils of E. graveolens (Inula graveolens). A paucity of data concerning E. incanus EOs was revealed, with the prevalence of 3-hydroxy-4-methoxy cinammic acid and thymol acetate noted in the oils. The EOs from E. multiradiatus and E. sublyratus were comprised mainly of matricaria and lachnophyllum esters. The available data on EOs of E. ramosus is limited, but the main constituents are known to be α-humulene, 1,8-cineole, eugenol, and globulol. The EOs containing appreciable amounts of matricaria and lachnophyllum esters exhibited strong anticancer, anti-inflammatory, antimicrobial, larvicidal, and repellent activities. Repellence is also related to borneol, bornyl acetate, caryophyllene derivatives, τ-cadinol, modhephen-8-β-ol, and cis-arteannuic alcohol. Cytotoxicity was determined due to the presence of limonene, δ-3-carene, α- and β-farnesene, (E)-β-ocimene, ledene oxide, sesquiphellandrene, and dendrolasin in the fleabanes EOs. Skin regeneration and antifungal properties were related to germacrene D; and anti-inflammatory effects were determined due to high amounts of limonene (E)-β-ocimene, lachnophyllum ester, and germacrene D. The antimicrobial properties of the oils were conditioned by appreciable quantities of limonene, β-pinene, 1,8-cineole, carvacrol, thymol acetae, β-eudesmol, 2,6,7,7α-tetrahydro-1,5-dimethyl-1H-indene-3-carboxaldehyde, caryophyllene and its oxide, allo-aromadendrene, α-humulene, farnesene, carvacrol, and eugenol. This review provides a foundation for further studies on volatile secondary metabolites to explore the potential sources of new biologically active compounds in Erigeron sp. Full article

Due to the growth in the application of antibacterial nanomaterials (NMs), there is an increased potential for ingestion by humans. Evidence shows that NMs can induce dysbiosis in the gut microbiota in vivo. However, in vitro investigation of the antibacterial activity of NMs on gut-relevant, commensal bacteria has been neglected, with studies predominantly assessing NM toxicity against pathogenic bacteria. The current study investigates the antibacterial activity of copper oxide (CuO) NMs to Escherichia coli K12, Enterococcus faecalis, and Lactobacillus casei using a combination of approaches and evaluates the importance of reactive oxygen species (ROS) production as a mechanism of toxicity. The impact of CuO NMs (100, 200, and 300 μg/mL) on the growth and viability of bacterial strains was assessed via plate counts, optical density (OD) measurements, well and disc diffusion assays, and live/dead fluorescent imaging. CuO NMs reduced the viability of all bacteria in a concentration-dependent manner in all assays except the diffusion assays. The most sensitive methods were OD measurements and plate counts. The sensitivity of bacterial strains varied depending on the method, but overall, the results suggest that E. coli K12 is the most sensitive to CuO NM toxicity. The production of ROS by all bacterial strains was observed via DCFH-DA fluorescent imaging following exposure to CuO NMs (300 μg/mL). Overall, the data suggests that CuO NMs have antibacterial activity against gut-relevant bacteria, with evidence that NM-mediated ROS production may contribute to reductions in bacterial viability. Our findings suggest that the use of a combination of assays provides a robust assessment of the antibacterial properties of ingested NMs, and in particular, it is recommended that plate counts and OD measurements be prioritised in the future when screening the antibacterial properties of NMs. Full article