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<i>In vivo</i> detection of endotracheal tube biofilms in intubated critical care patients using catheter-based optical coherence tomography
摘要： The formation of biofilms in the endotracheal tubes (ETTs) of intubated patients on mechanical ventilation is associated with a greater risk of ventilator-associated pneumonia (VAP) and death. New technologies are needed to detect and monitor ETTs in vivo for the presence of these biofilms. Longitudinal OCT imaging was performed in mechanically ventilated subjects at 24 hr intervals until extubation to detect the formation and temporal changes of in vivo ETT biofilms. OCT-derived attenuation coefficient images were used to differentiate between mucus and biofilm. Extubated ETTs were examined with optical and electron microscopy, and all imaging results were correlated with standard-of-care clinical test reports. OCT and attenuation coefficient images from 4 subjects were positive for ETT biofilms and were negative for 2 subjects. The processed and stained extubated ETTs and clinical reports confirmed the presence/absence of biofilms in all subjects. Our findings confirm that OCT can detect and differentiate between biofilm-positive and biofilm-negative groups (p < 10-5). OCT image-based features may serve as biomarkers for direct in vivo detection of ETT biofilms and help drive investigation of new management strategies to reduce the incidence of VAP.
关键词： attenuation coefficient image,endotracheal tube,biofilm,optical coherence tomography,ventilator-associated pneumonia
更新于2025-11-21 11:24:58
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Peptide Conjugated CuS Nanocomposites for NIR Triggered Ablation of Pseudomonas aeruginosa Biofilm
摘要： The Gram-negative bacteria Pseudomonas aeruginosa is one famous bacterial strain owing to its ability to effectively form biofilms, which is a front-line mechanism of bacterial tolerance. Herein, the near-infrared-induced nanocomposites were one-step prepared by modifying copper sulfide nanoparticle with peptide to effectively eradicate Pseudomonas aeruginosa biofilm through electrostatic interaction, photodynamic effect and photothermal effect. These nanocomposites could rapidly adhere to the surface of bacteria, and irreversible damage the bacterial membrane under near-infrared laser irradiation. Furthermore, the nanocomposites could selectively eliminate bacteria over mammalian cell without distinct toxicity to NIH 3T3 cells. The nanocomposites will exert a far-reaching impact on the future design of biocompatible near-infrared-induced antibacterial agents, exhibiting its potential applications in Gram-negative bacteria and biofilm infections.
关键词： copper sulfide nanoparticles,near-infrared laser,Gram-negative bacterial biofilm,photothermal and photodynamic effect
更新于2025-11-14 17:03:37
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Could a chelant improve the effect of curcumin-mediated photodynamic antimicrobial chemotherapy against dental intact biofilms?
摘要： To our knowledge, there is still no evidence in relation to the combination of curcumin with chelants to improve the effects of antimicrobial photodynamic therapy (aPDT) on complex dental caries biofilms. Therefore, the aim of this study was to evaluate the antimicrobial effect of curcumin-ethylenediaminetetraacetic acid (EDTA)-mediated aPDT on the vitality of intact biofilms of dentin caries microcosms. Biofilms were grown on glass slabs in McBain medium plus 1% sucrose in microaerophily at 37 °C for 5 days. Then, biofilms were treated with associations of 600 μmol L?1 curcumin combined or not with 1% EDTA and 37.5 or 75 J cm?2 LED (455 nm). The vitality was determined by a confocal laser scanning microscopy (CLSM) after staining biofilms with a mixture of 2.5 g L?1 fluorescein diacetate and 0.25 g L?1 ethidium bromide. Statistical analysis was conducted by Kruskal-Wallis and post hoc Dunn’s test (P < 0.05). Three treatments were able to reduce the vitality of overall biofilms: curcumin + 75 J cm?2 LED, curcumin-EDTA + 37.5 J cm?2 LED, and curcumin-EDTA + 75 J cm?2 LED. Also, the vitality of inner layers of biofilms was significantly reduced only after the combination of aPDT with EDTA. Therefore, the association of curcumin and EDTA improved the antimicrobial effect of aPDT on dentin caries microcosms, considering the application of lower light densities and deeper layers of biofilms.
关键词： Curcumin,Biofilm,Ethylenediaminetetraacetic acid,Dental caries,Photochemotherapy
更新于2025-09-23 15:23:52
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Visible light sensitive Ag/TiO2/graphene composite as a potential coating material for control of Campylobacter jejuni
摘要： Infectious diarrhea caused by the food borne pathogen, Campylobacter jejuni, is a major threat to public health worldwide leads high incidence of child mortality each year. In the present study, hydrothermal synthesis of Silver-Graphene-TiO2 nanocomposites along with TiO2, TiO2-Graphene and TiO2-silver nanocomposites was done and the samples were characterized using X-ray diffraction (XRD), tunneling electron microscopy (TEM) and UV-Vis Spectroscopy. Effect of silver and graphene addition on the broad spectrum antibacterial ability of TiO2 was studied under visible light. Moreover, the effects on bacterial survival, membrane integrity, cellular motiltiy and biofilm formation of C. jejuni were also evaluated. A synergetic effect of silver and graphene on Silver-Graphene-TiO2 nanocomposites was observed as indicated by its increased visible light sensitivity and enhanced antibacterial activity under visible light compared to its parent derivatives. Silver-Graphene-TiO2 composites effectively reduced growth and caused leakage of protein and DNA from C. jejuni cell. Atomic Force Microscopy was used to confirm bacterial cell damage. Besides, it also reduced motillity, hydrophobicity and autoaggregation of C. jejuni and showed excellent inhibition of biofilm formation. Furthermore, no significant cytotoxicity of synthesized nanoparticles was observed in human cell lines. We propose that Silver-Graphene-TiO2 composites can be used as effective antimicrobial agents to control the spread of C. jejuni by preventing both bacterial growth and biofilm formation.
关键词： TiO2,Campylobacter jejuni,photocatalytic,nanocomposite,biofilm,graphene,cytotoxicity,silver
更新于2025-09-23 15:23:52
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Antimicrobial photodynamic inactivation of fungal biofilm using amino functionalized mesoporus silica-rose bengal nanoconjugate against Candida albicans
摘要： Candida albicans is an opportunistic fungal pathogen that causes both superficial and systemic infection and an important candidate that contribute to high morbidity and mortality rates in immunocompromised patients. The ability of C. albicans to switch from yeast to filamentous form and thereby forming biofilms make them resistant to most of the antifungal drugs available today. Thus the development of more effective antifungal drugs are essential and crucial at this point of time. Antimicrobial photodynamic therapy is an alternative modality to treat such biofilm forming resistant strains. This study aims to investigate the enhanced efficiency of newly synthesized MSN-RB conjugate as an antimicrobial photosensitizer for antimicrobial photodynamic therapy against C. albicans. Functionalization of MSN with amino groups was performed to increase the dye loading capacity. Conjugation process of MSN-RB was confirmed using different techniques including UV–Vis spectroscopy, Fluorescent spectroscopy and FTIR analysis. A low power green laser 50 mW irradiation was applied (5 min) for activation of MSN-RB conjugate and RB against C. albicans biofilm and planktonic cell. The comparative study of MSN-RB conjugate and free RB on aPDT was evaluated using standard experimental procedures. Antibiofilm efficacy was determined using biofilm inhibition assay, cell viability, EPS quantification and CLSM studies. The results revealed that MSN-RB conjugate has a significant antimicrobial activity (88.62 ± 3.4%) and antibiofilm effect on C. albicans when compared to free dye after light irradiation. The MSN-RB conjugate based aPDT can be employed effectively in treatment of C. albicans infections.
关键词： Antimicrobial photodynamic therapy,Conjugation,Amino functionalization,Mesoporus silica nanoparticles,Lipid peroxidation,Anti-biofilm activity
更新于2025-09-23 15:23:52
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Synergistic in vitro effects of indocyanine green and ethylenediamine tetraacetate-mediated photodynamic antimicrobial chemotherapy combined with antibiotics for resistant bacterial biofilms in diabetic foot infection
摘要： Background: Antibiotic resistance has emerged as one of the most important determinants in diabetic foot infections outcomes. Photodynamic antimicrobial chemotherapy (PACT) has been proposed as an alternative approach for inactivating bacteria, especially resistant bacterial biofilms. This research investigated the synergistic effects of PACT mediated by the photosensitizer indocyanine green (ICG) and ethylenediamine tetraacetate (EDTA) combined with antibiotics against common pathogens of diabetic foot ulcer infection, including Staphylococcus aureus and Pseudomonas aeruginosa, in vitro. Methods: Planktonic bacteria and biofilms of S. aureus and P. aeruginosa were incubated with ICG and EDTA, and then exposed to laser treatment. Quantitative viable counting estimates the phototoxic effects on S. aureus and P. aeruginosa. The susceptibility of methicillin-resistant S. aureus (MRSA) and multidrug-resistant P. aeruginosa (MRPA) to PACT treatment was detected by disk diffusion and micro-broth dilution methods. Confocal microscopy was used to detect the morphology of biofilms treated with PACT and antibiotics. The resazurin assay was used to quantify the metabolic activity of bacteria in biofilms. Results: PACT mediated by ICG and EDTA led to a more pronounced antibacterial effect in S. aureus and P. aeruginosa compared with ICG alone-mediated PACT. P. aeruginosa was more sensitive to ICG and EDTA-mediated PACT than S. aureus. After PACT treatment, the susceptibility of MRSA and MRPA to antibiotics increased. Furthermore, PACT combined with antibiotic treatment significantly contributed to killing bacteria in the biofilm and disrupting biofilm structure. Conclusions: ICG and EDTA-mediated PACT combined with antibiotics synergistically enhanced the effects of sterilization and biofilm destruction.
关键词： photodynamic antimicrobial chemotherapy,antibacterial effect,diabetic foot infection,bacterial biofilm,EDTA,indocyanine green
更新于2025-09-23 15:23:52
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Protection mechanisms of periphytic biofilm to photocatalytic nanoparticles (PNPs) exposure
摘要： Researchers are devoting great effort to combine photocatalytic nanoparticles (PNPs) with biological process to create efficient environmental purification technologies (i.e. intimately coupled photobiocatalysis). However, little information is available to illuminate the responses of multispecies microbial aggregates against PNP exposure. Periphytic biofilm, as a model multispecies microbial aggregate, was exposed to three different PNPs (CdS, TiO2, and Fe2O3) under Xenon lamp irradiation. There were no obvious toxic effects of PNP exposure on periphytic biofilm as biomass, chlorophyll content and ATPase activity were not negatively impacted. Enhanced production of extracellular polymetric substances (EPS) is the most important protection mechanism for periphytic biofilm against PNPs exposure. Although PNPs exposure produced extracellular superoxide radicals and caused intracellular reactive oxygen species (ROS) accumulation in periphytic biofilm, the interaction between EPS and PNPs could mitigate production of ROS while superoxide dismutase could alleviate biotic ROS accumulation in periphytic biofilm. The periphytic biofilms changed their community composition in the presence of PNPs by increasing the relative abundance of phototrophic and high nutrient metabolic microorganisms (Families Chlamydomonadaceae, Cyanobacteriacea, Sphingobacteriales and Xanthomonadaceae). This study provides insight into the protection mechanisms of microbial aggregates against simultaneous photogenerated and nanoparticle toxicity from PNPs.
关键词： community composition,EPS,reactive oxygen species,Periphytic biofilm,photocatalyst,nanoparticles
更新于2025-09-23 15:23:52
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Extremely Hydrophobic Zinc Oxide Micro/nanostructures on Stainless Steel Surfaces with Anti-biofilm Property
摘要： The extremely hydrophobic zinc oxide micro/nanostructures with microscale bundles and nanoscale rods were obtained by sol-gel method and hydrothermal method on stainless steel surfaces. The prepared extremely hydrophobic zinc oxide films were proven to possess excellent anti-biofilm property, which may lead to some new promising applications for inhibiting biofilm formation.
关键词： Hydrophobic surface,Zinc oxide,Anti biofilm
更新于2025-09-23 15:22:29
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Anti oral biofilm mouthwash nanoemulsion containing extract propolis and curcumin
摘要： Background:In the previous research propolis and curcumin have been reported to have biological activity as antibacterial. Both of those herbs can be developed as anti-oral biofilm mouthwash oral hygiene.Mouthwash is produced as nanoemulsion that promotes wide distribution throughout oral biofilm and effectively penetrates to target cell. Objective: This study aims to create the best mouthwash formulation with great physical characteristics and stability, and also proved as an anti-biofilm agent. Methods: Each propolis A.mellifera and curcumin Curcuma domestica Val. was formulated into a mouthwash using the combined method of homogenization, mixing and ultrasonication. There was a variation amount of Tween-80 and glycerin in each formulation to investigate its effect on stability. The proven formula with the greatest stability was continued to undergo antibiofilm assay. Results: Result of this study showed that formula with a ratio of Tween-80 and glycerin 2:1 (v/v) was found to be the best. Tween-80 and glycerin can’t work as a single surfactant to produce stable nanoemulsion. Propolis and curcumin mouthwash showed in vitro antibiofilm activities against Streptococcus mutans, the primer colony in the biofilm. Propolis mouthwash reported has better effectiveness with the MIC of biofilm formation was 5% v/v and % inhibition of 48,54%, respectively.Conclusion:Nanoemulsion propolis mouthwash is proven to have the higher effectiveness in inhibiting biofilm formation than curcumin mouthwash. It suggested nanoemulsion propolis can be developed as good oral hygiene mouthwash that cansignificantly reduce the number of oral bacteria and inhibit their proliferation.
关键词： curcumin,nanoemulsion,propolis,anti-biofilm,mouthwash
更新于2025-09-23 15:21:21
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Efficiency of sequential UV/H2O2 and biofilm process for the treatment of secondary effluent
摘要： In response to the shortage of water resources, multiple processes have been applied to turn wastewater secondary effluent (SE) into potable water. However, trace organic contaminants (TOrCs) and high concentrations of organic matter contained in SE pose a significant challenge to the reclamation. In this manuscript, combined UV-based and biofilm processes were used to treat the SE spiked with ibuprofen (IBU) and clofibric acid (CA). The efficiency of these sequential treatments was characterized in terms of changes in dissolved organic carbon (DOC), absorbance at 254 nm (A254), fluorescence excitation-emission matrix (FEEM), the concentration of IBU and CA, and molecular weight of SE. Parallel factor (PARAFAC) was applied as the analysis method for FEEM of the samples and two fluorescent components were successfully identified: humic-like substances (C1) and protein-like matter (C2). Large reductions in A254, C1, C2, IBU, and CA were observed during the UV-based processes, especially with the addition of H2O2. Nearly 50% of A254, 80% of the component C1 were decreased and almost complete removal of the component C2 and TOrCs was achieved by UV/2.0 mM H2O2 after 90-min treatment. During the oxidation processes, the formation of lower molecular weight (LMW) compounds was detected, and the biodegradability of the organic matters was greatly increased. Although no significant DOC reduction was obtained in UV-based processes, an obvious further DOC reduction (30~60%) was achieved by biofilm treatment following UV-based processes, especially after UV/H2O2 treatments. In the meantime, large amounts of LMW were removed in the biofilm treatment process. This manuscript provides an effective advanced treatment of SE for the removal of DOC and TOrCs, facilitating the wastewater reclamation.
关键词： Trace organic contaminants,Removal,Biofilm,Secondary effluent,Dissolved organic carbon,UV/H2O2
更新于2025-09-23 15:21:21