Biofilm Inhibition Research Articles (Page 1)

Streptococcus mutans is considered the main pathogen causing dental caries and has a strong ability to establish biofilms and respond to environmental stimuli, which are essential for its survival and cariogenicity. Fourteen two-component signal transduction systems (TCSs) in S. mutans have been reported to regulate a broad range of physiological processes such as bacterial biofilm formation, acid resistance, competence development, and toxic oxygen metabolite resistance. These systems collectively contribute to the cariogenicity of S. mutans by coordinating adaptive responses to environmental challenges. Among them, the VicRK system has been one of the most extensively studied, with epidemiological evidence linking vicK mutations to increased caries risk in children. Other TCSs, such as ComDE, LiaRS, CiaRH, and the orphan response regulator GcrR, also contribute to cariogenicity regulation. The present review summarizes the regulatory roles of TCSs in virulence traits of S. mutans, with an emphasis on those involved in biofilm formation, which highlights their potential as therapeutic targets to prevent dental caries through biofilm inhibition.

Targeting fungal biofilms: design, synthesis, biological and in silico studies of novel N-(5-undecyl-1,3,4-oxadiazol-2-yl)benzamide derivatives against Candida albicans.

In Vitro antibacterial activity of Lactiplantibacillus sp. cell-free supernatants against Porphyromonas gingivalis: A potential approach for oral health.

Unveiling key hub genes in E. coli biofilm formation: An in silico approach integrating differential gene expression, biosurfactant targeting, MD simulation and MM-PBSA free energy calculations.

Novel Cu4MgO5 nanoparticles: Investigating anticancer, antibacterial, anti-biofilm, and fimH gene-related biofilm inhibition in Uropathogenic Escherichia coli

LC-MS profiling of Terminalia chebula seed reveals mechanistic insights supporting activity against multidrug-resistant diabetic foot ulcer isolate.

The effect of gold nanoparticle size and shape on the structure and activity of Domain 3 of an alternative sigma factor of Staphylococcus aureus.

Abstract Multidrug-resistant (MDR) bacterial infections pose a major global health threat, necessitating innovative strategies to combat complex infections beyond conventional antibiotics. This study aimed to evaluate a freshly prepared dual-action nanoplatform integrating gold nanoparticles (AuNPs), chitosan (CS), and papain (Pap) for antibacterial, antibiofilm activities, with biocompatible outreach. The preparation previously achieved, AuNPs–CS–Pap, size averaged at ∼29 nm, and having a positive surface charge (+21.8 mV), exhibited strong antibacterial activity against Staphylococcus aureus , Streptococcus mutans , Klebsiella pneumoniae , and Escherichia coli , with minimum inhibitory concentrations as low as 3.12 µg mL −1 . The fractional inhibitory concentration index value (<0.5) confirmed the synergistic interaction. Biofilm inhibition reached 91%, significantly surpassing the performance of individual components of the nanomaterial. Acridine orange and ethidium bromide staining validated enhanced bacterial membrane disruption. In vivo toxicity studies in mice revealed no significant organ damage or alterations in liver/kidney functions, exhibiting the biocompatibility of the formulation. The novelty of this work lies in the exhibition of synergistic antibacterial activity affected by the presence of AuNPs, CS, and Pap as the nanoplatform constituents to provide a dual-action mechanism of biofilm degradation and reactive oxygen species-mediated bacterial killing. The biocompatibility findings confirmed the AuNPs–CS–Pap as a safe and effective nanoplatform for combating MDR infections and inhibition of biofilm-formation potential to combat infections.

Microbial infections are a major healthcare challenge, exacerbated by rising antibiotic resistance. This study aims to synthesize and characterize silver-based nanoparticles (Ag2O and Ag NPs) via conventional and green routes using Corchorus olitorius leaf extract. Structural, optical, and antibacterial properties were analyzed using XRD, FTIR, and UV-Vis spectroscopy. Antibacterial efficacy was evaluated through disc diffusion, MIC, MBC, and biofilm inhibition assays. Statistical analysis was performed using two-way ANOVA to ensure result reliability. The XRD analysis confirmed that S1 (conventional synthesis) consists of cubic Ag2O, while S2 (uncalcined green-synthesized NPs) and S3 (calcined green-synthesized NPs) exhibit cubic metallic Ag. The crystallite size increased from S2 (16.11 nm) to S3 (31.73 nm), with improved crystallinity (S3: 93.58%). SEM images revealed that green-synthesized nanoparticles (S2, S3) were more uniform and well-dispersed compared to S1. TG analysis indicated that calcination effectively removed organic residues, enhancing nanoparticle stability. Antibacterial tests demonstrated strong activity against E. coli and B. cereus, with S1 showing the highest inhibition. MIC and MBC values confirmed the bacteriostatic, and bactericidal nature of all samples, with S2 exhibiting the strongest effect on B. cereus. Antibiofilm results showed that all samples inhibited biofilm formation, particularly at high concentrations. Overall, green synthesis produced highly crystalline Ag NPs with enhanced stability and antimicrobial efficacy. Calcination further improved crystallinity and reduced defects, making S3 the most stable. These findings highlight the potential of Ag NPs for biomedical and environmental applications, with synthesis conditions significantly influencing their structural and biological properties.

Abstract Treating infectious diseases with current available antimicrobial drugs is extremely difficult due to biofilms that act as barriers and reduce the concentration of antimicrobial agents that reach the bacteria embedded in the biofilms. In this study, we hypothesized that extracellular polymeric substances (EPS)-binding liposomes anchor to biofilm matrices and sterically block the communication between bacteria, leading to biofilm inhibition. A 16-mer peptide, which binds to hyaluronic acid as one of the EPS, was covalently conjugated to PEG (polyethylene glycol)-lipid for producing EPS-binding liposomes. The effect of the liposomes on inhibiting or eradicating biofilm formation was investigated, compared to the bare liposomes. Dynamic light scattering (DLS) measurement results showed that the EPS-binding liposomes and bare liposomes have a particle size of < 200 nm and nearly neutral zeta potential. The molecular interaction of EPS extracted from S. aureus biofilm with EPS-binding liposomes and free EPS-binding peptides was determined using isothermal titration calorimetry (ITC) and the result revealed that EPS-binding liposome (Ka ~ 4.82 × 10 5 ) has better affinity than the free EPS-binding peptides (Ka ~ 1.79 × 10 3 ). The minimal biofilm inhibitory concentration (MBIC) assay showed EPS-binding liposomes have a better biofilm inhibition effect, in a dose-dependent manner, compared to the bare liposomes and free EPS-binding peptides. Physical disruption and blocking chemical communication via biofilm binding are likely a key mechanism behind the effectiveness of EPS-binding liposomes in biofilm inhibition although further study is needed.

The genus Eugenia has a long history of use in traditional medicine for treating various conditions, including infectious diseases, gastrointestinal disorders, and skin problems. Essential oils derived from Eugenia species are known for their medicinal properties and have been studied for their antimicrobial and bioactive potential. This study aimed to evaluate, through in vitro tests, the antibacterial, antibiofilm, and antibiotic-modulating effects of Eugenia brejoensis essential oil (EOEb) against multidrug-resistant (MDR) clinical isolates of Acinetobacter baumannii and Pseudomonas aeruginosa from COVID-19 patients. In addition, we sought to analyze its toxicity and survival rates through in vivo tests in an invertebrate model using Tenebrio molitor. The EOEb was extracted via hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS) and flame ionization detector (FID). Clinical isolates of A. baumannii and P. aeruginosa were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and their resistance profiles were determined using the Vitek 2 system. The in vitro tests were conducted using the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using microdilution and plating methods. Biofilm formation and inhibition assays were performed using crystal violet staining. Synergistic effects of EOEb with ciprofloxacin and gentamicin were evaluated using the checkerboard assay. The antibacterial effect of EOEb was tested in vivo using the T. molitor (mealworm) larvae model to assess toxicity and survival rates. The major constituents of EOEb were rosifoliol (16.47%), guaiol (12.69%), and (E)-caryophyllene (11.97%). All bacteria exhibited an MDR profile. EOEb showed significant antibacterial activity against MDR strains, with MIC and MBC values ranging from 0.512 to 4.096mg/mL. It also effectively inhibited biofilm formation at concentrations between 0.512 and 4.096mg/mL. EOEb exhibited synergistic effects with ciprofloxacin against A. baumannii and with gentamicin against P. aeruginosa, as indicated by fractional inhibitory concentration (FIC) indices close to 0.5. The EOEb demonstrated low toxicity in the T. molitor model, with a survival rate of approximately 70%. The EOEb exhibits notable antimicrobial and biofilm-inhibiting properties against MDR pathogens. Its low toxicity and synergistic effects with conventional antibiotics suggest its potential as a therapeutic alternative for combating antibiotic-resistant infections.

Background: Teeth are vital structures prone to issues such as caries and plaque formation, often caused by Streptococcus mutans (S. mutans). This issue can be mitigated using natural ingredients like mangosteen fruit (Garcinia mangostana L.), especially its peel, is known for its medicinal benefits. However, its extract may take time to show effects, so it is being combined with nanosilver for improved drug distribution. To observe the antibacterial and antibiofilm potential of Mangosteen Peel Extract (MPE) in nanosilver form as a preventive agent in dentistry. Methods: The extraction was succeeded by a phytochemical assay and biosynthesis of MPE into Mangosteen Peel Extract Nanosilver (MPNs). Particle Size Analysis (PSA) and Transmission Electron Microscopy (TEM) were used to study this procedure. Disc diffusion tests were used to evaluate the antibacterial properties, and the Minimum Inhibition Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were also determined. Furthermore, the antibiofilm activity against S. mutans was investigated. Results: the phytochemical contents in MPE were flavonoids, tannins, saponins, phenols, alkaloids, triterpenoids, and terpenoids. Particle size of MPNs was 126.1 nm and the Polydispersity Index (PDI) was 0.419. The highest antibacterial concentration as inhibition zone against S. mutans was 16.37±0.38 mm and 119.37±2.16% inhibitory activity, at the highest concentration (100%) p<0.05. The percentage of biofilm inhibition against S. mutans was 27.64-105.94% which was concentration dependent. Conclusion: MPNs has potential as an antibacterial and antibiofilm agent that can be used as a preventive agent in medicine.

Abstract Hospital-acquired infections triggered by multidrug-resistant Staphylococcus aureus are a major clinical problem because of the bacterium’s capacity to build biofilms on medical surfaces. The purpose of this work was to evaluate the antibiofilm activity of green-synthesised iron nanoparticles (FeNPs) produced from Bauhinia purpurea leaf extract. The FeNPs were studied by UV-Visible spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM), revealing an absorbance peak at 320–330 nm, a crystalline structure with an average size of 32 nm, and a spherical shape ranging from 100 to 200 nm. The antibiofilm efficiency was investigated using a crystal violet-based microtiter plate assay. The results revealed concentration-dependent inhibition, with a maximum of 92.74% biofilm inhibition at 500 µg/mL and 35.48% inhibition at the lowest dosage of 31.25 µg/mL. SEM imaging revealed the reduced bacterial adhesion and disturbed biofilm architecture on the treated surfaces. This study is unique in that it is the first to demonstrate B. purpurea -mediated FeNPs as effective, environmentally friendly antibiofilm agents with prospective implications in avoiding biofilm-associated infections on medical equipment.

Synergistic bactericidal and antibiofilm effects of curcumin and nisin dual-loaded liposomes combined with photodynamic treatment on Listeria monocytogenes.

Abstract The rise of multidrug‐resistant (MDR) pathogens and the limitations of conventional antibiotics have led to the need for alternative therapeutic strategies. This study investigates the synthesis, structural characterization, and bioactive properties of ZnNiAl mixed metal oxide (MMO) nanoparticles derived from calcined layered double hydroxides (ZnNiAl‐LDH). The nanocomposites were calcined at various temperatures, including 400, 600, and 800 °C. The materials were characterized using X‐ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). The nanocomposites showed superior antimicrobial properties, with MICs ranging from 1.95 to 15.62 µg/mL against tested pathogens. Biofilm inhibition assays revealed enhanced efficacy at 800 °C, with IC50 values of 56.79 µg/mL for Staphylococcus aureus , 54.53 µg/mL for Pseudomonas aeruginosa , and 64.17–77.13 µg/mL for Candida albicans . The 800 °C nanocomposites also demonstrated superior antioxidant activity and significant cytotoxicity against HT29 colorectal cancer cells. These findings point out the advantages of ZnNiAl nanocomposites as multifunctional nanotherapeutics, offering a promising strategy for therapeutic applications against microbial infections and cancer progression.

This study aimed to characterize indigenous yeasts from Tulum cheese as potential starter/adjunct cultures through molecular, technological, probiotic, and postbiotic analyses. Yeasts were isolated from four Tulum batches during the ripening process. Based on interspecific genetic diversity assessed by iPBS and SCoT markers, the isolates were identified as Debaryomyces hansenii, Wickerhamomyces anomalus, Torulaspora delbrueckii, Kluyveromyces lactis, K. marxianus, Pichia kudriavzevii, P. membranifaciens, Yarrowia lipolytica, and Geotrichum candidum by ITS sequencing. Genetically diverse strains were selected and subjected to technological characterization. Principal component analysis highlighted K. lactis and K. marxianus strains mainly for their acidification ability, proteolytic activity, acetoin production, and carbon assimilation profiles. In vitro probiotic evaluations further distinguished K. marxianus TP3M11, TP3M28, and K. lactis TP4M30 for their high tolerance to simulated gastric conditions, elevated cell surface hydrophobicity, and their postbiotics' strong antioxidant capacity and biofilm inhibition capacity against Staphylococcus aureus ATCC 25,923. These findings support the potential application of selected yeast strains as multifunctional cultures in food biotechnology.

An emerging area of nanotechnology is the microbial synthesis of nanoparticles, which provides environmentally acceptable and sustainable substitutes for traditional physical and chemical manufacturing techniques. As natural nano factories, microorganisms like bacteria, fungus, actinomycetes, and microalgae mediate the reduction and stabilization of metal ions into nanoparticles with distinct physicochemical characteristics. These biogenic nanoparticles have great promise for use in a variety of industries, such as biofilm management, sustainable agriculture, and biomedical applications. They serve as nano-fertilizers, nano herbicides, and nano fungicides in agriculture, improving crop output, nutrient availability, and disease resistance while lessening their negative effects on the environment. They are useful instruments in the fight against persistent microbial communities in industrial, medicinal, and environmental settings because of their strong antibacterial qualities and capacity to break down biofilms. New research also shows how microplastics and nanoparticles interact in vascular settings, which may help explain how atheroma develops and how cardiovascular health is affected. The synthesis processes, structural and functional diversity, and uses of microbial nanoparticles in many industries are examined in this review. In addition, it examines how nanotechnology might be used to mitigate the health hazards associated with microplastics while assessing issues with toxicity, environmental destiny, and regulatory mechanisms. A strong, long-lasting framework for tackling urgent issues in environmental health, healthcare, and agriculture is provided by microbial nanotechnology taken together.

Abstract This report details the synthesis and evaluation of a series of novel imidazo[1,2‐c]pyrimidine‐1,2,4‐oxadiazole‐isoxazole derivatives, aimed at discovering improved antibacterial and antibiofilm agents through in vitro analysis. The antibacterial efficacy was assessed against three bacterial strains, specifically Staphylococcus aureus . Among the compounds evaluated, 3‐(7‐chloro‐2‐methylimidazo[1,2‐c]pyrimidin‐3‐yl)‐5‐(3‐(3,5‐dichlorophenyl)isoxazol‐5‐yl)‐1,2,4‐oxadiazole and 3‐(7‐chloro‐2‐methylimidazo[1,2‐c]pyrimidin‐3‐yl)‐5‐(3‐(4‐fluorophenyl) isoxazol‐5‐yl)‐1,2,4‐oxadiazole demonstrated significant antibacterial efficacy against the bacterial strains tested, with minimum inhibitory concentration (MIC) values spanning from 1.56 ± 0.12 to 6.25 ± 0.75 µg/mL. Additionally, compounds 3‐(7‐chloro‐2‐methylimidazo[1,2‐c]pyrimidin‐3‐yl)‐5‐(3‐(4‐chloro‐3,5‐dimethoxyphenyl)isoxazol‐5‐yl)‐1,2,4‐oxadiazole and 3‐(7‐chloro‐2‐methylimidazo[1,2‐c]pyrimidin‐3‐yl)‐5‐(3‐(4‐chlorophenyl)isoxazol‐5‐yl)‐1,2,4‐oxadiazole exhibit equivalent activity against the MSSA strain. The results indicated that compound 3‐(7‐chloro‐2‐methylimidazo[1,2‐c]pyrimidin‐3‐yl)‐5‐(3‐(3,5‐dichlorophenyl)isoxazol‐5‐yl)‐1,2,4‐oxadiazole exhibited significant biofilm inhibition against methicillin‐susceptible S. aureus (MSSA) and methicillin‐resistant S. aureus (MRSA), with MIC values of 3.12 ± 0.09 and 4.61 ± 0.22 µg/mL, respectively. In silico studies were conducted to examine the interactions of stronger compounds with TLR4 proteins (PDB: 3FXI, 3VQ1, 3RG1), revealing that all strong compounds exhibited superior binding energy compared to the reference. Finally, the in silico pharmacokinetic profile was predicted for potent compounds using SWISS/ADME and pkCSM. The majority of the tested compounds comply with Lipinski's Rule of Five.

This study reports the biosynthesis of selenium nanoparticles (Se-NPs) using four newly isolated strains of lactic acid bacteria, molecularly identified as Lactiplantibacillus pentosus, Lactiplantibacillus plantarum, Lactiplantibacillus plantarum, and Lactobacillus acidophilus. The synthesized Se-NPs were characterized using Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDX), Fourier Transform Infrared Spectroscopy (FTIR), and UV-Vis Spectroscopy, and zeta potential analysis. The result revealed that their size ranged from 16 nm to 90 nm with favorable stability and purity. The Se-NPs exhibited significant antimicrobial and antibiofilm activities against certain Gram-positive, Gram-negative bacteria, and Candida albicans, particularly those produced by isolate S4, which showed the lowest MIC values and highest biofilm inhibition. Furthermore, MTT assays revealed selective cytotoxicity against the A549 cancerous lung cell line, with minimal toxicity toward normal Wi38 cells. These findings suggest that biosynthesized Se-NPs are a promising, biocompatible candidate for combating antibiotic-resistant pathogens and biofilm-associated infections.

Carbon dots (CDs) are nanoscale carbon-based nanomaterials with tunable fluorescence, excellent aqueous solubility, and favorable biocompatibility. Among green synthesis strategies, microbial systems have gained growing attention due to their scalable cultivation, intrinsic heteroatom doping, and metabolite-driven surface functionalization. Microbial CD formation proceeds through hydrothermal or microwave-assisted carbonization of microbial biomass and extracellular polymers, driving hydrolysis, dehydration, aromatization, and graphitization to yield sp²/sp³ carbon cores enriched with hydroxyl, carboxyl, and amine groups. Characterization studies consistently report nanoscale size, graphitic lattice fringes, and excitation-dependent fluorescence, though quantum yields and photostability remain inconsistent. Applications span biosensing, antimicrobial therapy, bioimaging, catalysis, packaging, and agriculture, with studies demonstrating nanomolar-level detection sensitivity, selective heavy-metal discrimination, and inhibition of biofilms and drug-resistant pathogens. Biocompatibility assessments show high mammalian cell viability at application-relevant concentrations, although long-term biosafety data remain limited and require further investigation. By consolidating mechanistic insights, performance benchmarks, and comparative critique, this review positions microbial CDs as a distinct and underexplored branch of green nanomaterials with strong potential for biomedical and environmental translation. To our knowledge, this is the first comprehensive review exclusively focused on microbial carbon dots, systematically comparing bacteria, fungi, and yeasts as sustainable nanocarbon platforms.