Berberine Chloride Dihydrate Enthused Nanovesicles for the Management of Dermatitis

Background: Dermatitis is a common inflammatory skin disease that is affecting up to 25% of children and 1%-3% of adults worldwide. Paucity of exact cure for dermatitis and untoward side effects of topical immunosuppressive steroids has resulted into a great need for making use of complementary medicine to treat dermatitis. Objective: The present research work involved the development of Berberine chloride dihydrate (BCD) enthused nanovesicles i.e. ethosomes for the management of dermatitis. Method: Ethosomes were prepared by slight modification of cold method using varying concentrations of SPC (1-3%) and ethanol (10-40%) Optimized batch BCD 12 was further added to Carbopol 934P for gel formation. GEL BCD 12 was subjected to “anti-bacterial, dermatitis and skin irritation study. Result: The vesicles were in size range 142.42-398.31 nm while polydispersity index (PDI) ranges from 0.114-1.56 and for zeta potential it was from-18.8 to -39.4. Entrapment efficiency was from 46.05-88.79 %. Confocal laser scanning microscopy showed penetration depth of rhodamine enthused ethosome across rat skin upto 110 µm which was significantly higher than rhodamine solution (10 µm). In the anti-bacterial study, BCD loaded ethosomal gel (EG) showed maximum zone of inhibition of 18.5 mm against E. coli, 14.5 mm against P. aeruginosa and 23.0 mm against S. aureus. In dinitrochlorobenzene (DNCB) induced mice dermatitis model histopathology study showed marked decrease in amount of inflammatory cell nucleus in mice treated with BCD loaded ethosomal gel followed by 56% and 50 % increase in ear swelling and ear mass respectively in morphology study. Conventional marketed formulation showed nominal decrease in epidermal thickness, 66.67 % increase in ear thickness and 63.64 % increase in ear mass. Further Primary irritation index was less than 0.4 indicating negligible irritation in all the groups. Conclusion: It can be concluded that ethosomal gel is not only an efficient carrier for BCD but also proves its potential for the management of dermatitis.

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Investigating the potential of Quercetin enthused nano lipoidal system for the management of dermatitis

Research Journal of Pharmacy and Technology ◽

10.52711/0974-360x.2021.01127 ◽

2021 ◽

pp. 6516-6526

Author(s):

Deepti Dwivedi ◽

Shubham Pandey ◽

Shafaque Asif ◽

Vineet Awasthi ◽

Gurjeet Kaur ◽

...

Keyword(s):

Zeta Potential ◽

Skin Permeation ◽

Research Work ◽

Entrapment Efficiency ◽

Laser Scanning Microscopy ◽

Polydispersity Index ◽

In Vivo Studies ◽

Confocal Laser ◽

Skin Retention

Objective: The present research work was undertaken to develop quercetin enthused nanolipoidal systems and its characterization. The objective was to investigate potential of prepared system in the management of DNCB induced dermatitis. Method: Nanolipoidal system was prepared in different combinations with quercetin, L-α phosphatidylcholine (SPC) and ethanol and characterized for particle size, polydispersity index (PDI), zeta potential, drug entrapment efficiency, percentage drug release, skin retention and skin permeation. Selected batches were further incorporated into Carbopol 934 base gel. The vesicles were in size range 324.19-359 nm while polydispersity index (PDI) ranges from 0.241-0.554 and for zeta potential, it was from -26.33 to -39.3 nm. Entrapment efficiency was from 23.77-94.68 %. Confocal laser scanning microscopy showed penetration depth of rhodamine enthused ethosome across rat skin up to 45.23 µm which was significantly higher than the rhodamine solution (10 µm). In dinitrochlorobenzene (DNCB) induced mice dermatitis model histopathology study showed a marked decrease in amount of inflammatory cell nucleus in mice treated with quercetin loaded ethosomal gel followed by 76.13% decrease in-ear swelling and ear mass respectively in morphology study. The conventional marketed formulation showed a nominal decrease in epidermal thickness. Further Primary irritation index was less than 0.4 indicating negligible irritation in all the groups. Results: The optimized formulation F6 with SPC and ethanol in the ratio of 20:80 displayed the highest drug content and entrapment efficiency of 94.68±1.14%. PDI was 0.241±0.11 and skin retention 7.7%. Batch F6 with vesicle size and zeta potential of 324.9±19 nm and -26.33 mV, respectively, was incorporated in Carbopol 934 base gel and the prepared gel was evaluated for morphology, spreadability, in vitro, ex vivo release study, and kinetics study and in vivo studies. Conclusion: The present study revealed that the developed ethosomal gel can be used for enhanced delivery of Quercetin via skin. The in vitro studies indicated that the gel serves as an efficient carrier for Quercetin. It showed its effectiveness in the management of dermatitis. Further, Quercetin loaded nanoethosomal gel formulation can be viewed as a promising drug delivery system for the management of dermatitis.

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The Chromosomal Toxin Gene yafQ Is a Determinant of Multidrug Tolerance for Escherichia coli Growing in a Biofilm

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00043-09 ◽

2009 ◽

Vol 53 (6) ◽

pp. 2253-2258 ◽

Cited By ~ 126

Author(s):

Joe J. Harrison ◽

William D. Wade ◽

Sarah Akierman ◽

Caterina Vacchi-Suzzi ◽

Carol A. Stremick ◽

...

Keyword(s):

Escherichia Coli ◽

Stationary Phase ◽

Cell Survival ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Cell Counting ◽

Confocal Laser ◽

Toxin Gene ◽

Persister Cells ◽

E Coli

ABSTRACT Escherichia coli is refractory to elevated doses of antibiotics when it is growing in a biofilm, and this is potentially due to high numbers of multidrug-tolerant persister cells in the surface-adherent population. Previously, the chromosomal toxin-antitoxin loci hipBA and relBE have been linked to the frequency at which persister cells occur in E. coli populations. In the present study, we focused on the dinJ-yafQ-encoded toxin-antitoxin system and hypothesized that deletion of the toxin gene yafQ might influence cell survival in antibiotic-exposed biofilms. By using confocal laser scanning microscopy and viable cell counting, it was determined that a ΔyafQ mutant produced biofilms with a structure and a cell density equivalent to those of the parental strain. In-depth susceptibility testing identified that relative to wild-type E. coli, the ΔyafQ strain had up to a ∼2,400-fold decrease in cell survival after the biofilms were exposed to bactericidal concentrations of cefazolin or tobramycin. Corresponding to these data, controlled overexpression of yafQ from a high-copy-number plasmid resulted in up to a ∼10,000-fold increase in the number of biofilm cells surviving exposure to these bactericidal drugs. In contrast, neither the inactivation nor the overexpression of yafQ affected the tolerance of biofilms to doxycycline or rifampin (rifampicin). Furthermore, deletion of yafQ did not affect the tolerance of stationary-phase planktonic cells to any of the antibacterials tested. These results suggest that yafQ mediates the tolerance of E. coli biofilms to multiple but specific antibiotics; moreover, our data imply that this cellular pathway for persistence is likely different from that of multidrug-tolerant cells in stationary-phase planktonic cell cultures.

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Inhibition of Escherichia coli Biofilm Formation by Self-Assembled Monolayers of Functional Alkanethiols on Gold

Applied and Environmental Microbiology ◽

10.1128/aem.02633-06 ◽

2007 ◽

Vol 73 (13) ◽

pp. 4300-4307 ◽

Cited By ~ 53

Author(s):

Shuyu Hou ◽

Erik A. Burton ◽

Karen A. Simon ◽

Dustin Blodgett ◽

Yan-Yeung Luk ◽

...

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Amide Bond ◽

Self Assembled Monolayers ◽

Confocal Laser ◽

E Coli ◽

Assembled Monolayers ◽

Self Assembled

ABSTRACT Bacterial biofilms cause serious problems, such as antibiotic resistance and medical device-related infections. To further understand bacterium-surface interactions and to develop efficient control strategies, self-assembled monolayers (SAMs) of alkanethiols presenting different functional groups on gold films were analyzed to determine their resistance to biofilm formation. Escherichia coli was labeled with green florescence protein, and its biofilm formation on SAM-modified surfaces was monitored by confocal laser scanning microscopy. The three-dimensional structures of biofilms were analyzed with the COMSTAT software to obtain information about biofilm thickness and surface coverage. SAMs presenting methyl, l-gulonamide (a sugar alcohol tethered with an amide bond), and tri(ethylene glycol) (TEG) groups were tested. Among these, the TEG-terminated SAM was the most resistant to E. coli biofilm formation; e.g., it repressed biofilm formation by E. coli DH5α by 99.5% ± 0.1% for 1 day compared to the biofilm formation on a bare gold surface. When surfaces were patterned with regions consisting of methyl-terminated SAMs surrounded by TEG-terminated SAMs, E. coli formed biofilms only on methyl-terminated patterns. Addition of TEG as a free molecule to growth medium at concentrations of 0.1 and 1.0% also inhibited biofilm formation, while TEG at concentrations up to 1.5% did not have any noticeable effects on cell growth. The results of this study suggest that the reduction in biofilm formation on surfaces modified with TEG-terminated SAMs is a result of multiple factors, including the solvent structure at the interface, the chemorepellent nature of TEG, and the inhibitory effect of TEG on cell motility.

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Aqueous mechano-bactericidal action of acicular aragonite crystals

Scientific Reports ◽

10.1038/s41598-021-98797-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Nobuaki Negishi ◽

Tomohiro Inaba ◽

Yukari Miyazaki ◽

Genki Ishii ◽

Yingnan Yang ◽

...

Keyword(s):

Laser Scanning ◽

Hard Water ◽

Petri Dish ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Black Silicon ◽

Bacterial Cells ◽

Bactericidal Action ◽

E Coli ◽

Biological Affinity

AbstractNanoneedle structures on dragonfly and cicada wing surfaces or black silicon nanoneedles demonstrate antibacterial phenomena, namely mechano-bactericidal action. These air-exposed, mechano-bactericidal surfaces serve to destroy adherent bacteria, but their bactericidal action in the water is no precedent to report. Calcium carbonate easily accumulates on solid surfaces during long-term exposure to hard water. We expect that aragonite nanoneedles, in particular, which grow on TiO2 during the photocatalytic treatment of calcium-rich groundwater, exhibit mechano-bactericidal action against bacteria in water. Here, we showed that acicular aragonite modified on TiO2 ceramics prepared from calcium bicarbonate in mineral water by photocatalysis exhibits mechanical bactericidal activity against E. coli in water. Unmodified, calcite-modified and aragonite-modified TiO2 ceramics were exposed to water containing E. coli (in a petri dish), and their bactericidal action over time was investigated under static and agitated conditions. The surfaces of the materials were observed by scanning electron microscopy, and the live/dead bacterial cells were observed by confocal laser scanning microscopy. As a result, the synergistic bactericidal performance achieved by mechano-bactericidal action and photocatalysis was demonstrated. Aragonite itself has a high biological affinity for the human body different from the other whisker-sharpen nanomaterials, therefore, the mechano-bactericidal action of acicular aragonite in water is expected to inform the development of safe water purification systems for use in developing countries.

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Biocoatings: Painting bacteria on surfaces

Access Microbiology ◽

10.1099/acmi.ac2020.po0333 ◽

2020 ◽

Vol 2 (7A) ◽

Author(s):

Simone Krings ◽

Yuxiu Chen ◽

Suzie Hingley-Wilson ◽

Joseph L. Keddie

Keyword(s):

Laser Scanning ◽

Fluorescent Protein ◽

Yellow Fluorescent Protein ◽

Inorganic Nanoparticles ◽

Laser Scanning Microscopy ◽

Polymer Materials ◽

Latex Film ◽

Confocal Laser ◽

Bacterial Cells ◽

E Coli

Background: Biocoatings are nanoporous polymer materials which encapsulate bacterial cells with carbohydrates as osmoprotectants. Here, we optimised biocoatings to offer a favourable environment for the metabolic activity of bacteria. Methods: E. coli were used as a model organism and mixed with the colloidal polymer particles (i.e. synthetic latex), inorganic nanoparticles and different carbohydrates. Films were casted and dried to create a coalesced latex film and finally rehydrated to re-establish bacterial metabolism. The toxicity of the sterile latices to the bacteria was tested by using the colourimetric redox indicator resazurin. Visualisation of the bacteria inside the biocoatings was performed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Results: We introduced halloysite (clay nanotubes) to create nanoporosity, which created voids in the structure that will permit gas exchange. The biocoatings were tested in liquid and rehydrated states with resazurin to find the most promising composition ensuring bacterial viability. Rehydrated biocoatings were visualised by CLSM by tracking the constitutively expressed yellow-fluorescent protein (YFP) for viable cells and the membrane exclusion dye propidium iodide for dead cells. The structure of the biocoatings appeared to be unaffected by freeze-drying compared to chemical fixation. Following this fixation, SEM allowed the observation of the organisation of the latex polymers, halloysite and bacteria. Conclusions: The biocoatings were highly porous thanks to halloysite. E. coli survived the film formation process. Next, we will use E. coli and cyanobacteria to achieve higher efficiency for a variety of applications e.g. pollutant degradation, solar energy harvesting and carbon recycling.

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Effect of Lactobacillus plantarum Biofilms on the Adhesion of Escherichia coli to Urinary Tract Devices

Antibiotics ◽

10.3390/antibiotics10080966 ◽

2021 ◽

Vol 10 (8) ◽

pp. 966

Author(s):

Fábio M. Carvalho ◽

Rita Teixeira-Santos ◽

Filipe J. M. Mergulhão ◽

Luciana C. Gomes

Keyword(s):

Escherichia Coli ◽

Urinary Tract ◽

Lactobacillus Plantarum ◽

Laser Scanning ◽

Optimal Growth ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Novel Technologies ◽

E Coli ◽

Static Conditions

Novel technologies to prevent biofilm formation on urinary tract devices (UTDs) are continually being developed, with the ultimate purpose of reducing the incidence of urinary infections. Probiotics have been described as having the ability to displace adhering uropathogens and inhibit microbial adhesion to UTD materials. This work aimed to evaluate the effect of pre-established Lactobacillus plantarum biofilms on the adhesion of Escherichia coli to medical-grade silicone. The optimal growth conditions of lactobacilli biofilms on silicone were first assessed in 12-well plates. Then, biofilms of L. plantarum were placed in contact with E. coli suspensions for up to 24 h under quasi-static conditions. Biofilm monitoring was performed by determining the number of culturable cells and by confocal laser scanning microscopy (CLSM). Results showed significant reductions of 76%, 77% and 99% in E. coli culturability after exposure to L. plantarum biofilms for 3, 6 and 12 h, respectively, corroborating the CLSM analysis. The interactions between microbial cell surfaces and the silicone surface with and without L. plantarum biofilms were also characterized using contact angle measurements, where E. coli was shown to be thermodynamically less prone to adhere to L. plantarum biofilms than to silicone. Thus, this study suggests the use of probiotic cells as potential antibiofilm agents for urinary tract applications.

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Functionalising antibiotics with nitroxides as an effective broad-spectrum biofilm eradication strategy.

10.5194/biofilms9-12 ◽

2020 ◽

Author(s):

Anthony Verderosa ◽

Kathryn Fairfull-Smith ◽

Makrina Totsika

Keyword(s):

Laser Scanning ◽

Antimicrobial Agents ◽

Bacterial Species ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Specific Test ◽

E Coli ◽

Cell Counts ◽

Eradication Strategy ◽

New Generation

Background: The adhesion of planktonic bacteria to a surface (biotic or abiotic), and their subsequent ability to aggregate into multicellular communities called biofilms, is a major driving force of failing antibiotic therapy and persistence in chronic infections caused by a variety of pathogens (e.g., Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus)&#160;and plaguing healthcare systems worldwide. Biofilms are estimated to be involved in over 80% of all microbial infections in humans, and commonly exhibit extreme resistance to conventional antimicrobial treatments. Consequently, there is an urgent need for novel antimicrobial agents, which target biofilm residing cells. Here, we present the development and evaluation of a new generation of dual-acting nitroxide functionalised antibiotics with potent biofilm eradication activity. Methodology: Synthetic organic chemistry was utilised to produce a new generation of nitroxide functionalised antibiotics with targeted biofilm eradication capabilities. These compounds were tested for biofilm eradication and/or dispersal of several bacterial species using the MBECTM device, a reproducible high-throughput static biofilm formation system. Mature biofilms were treated with serial dilutions of the specific test agent(s) and recovered bacterial numbers were quantified by absorbance spectroscopy at 600 nm or plating for viable cell counts. Treated biofilms were also stained with Live/Dead (SYTO-9/PI) bacterial viability kit and analysed by fluorescence and confocal laser scanning microscopy. Results: Nitroxide functionalised antibiotics exhibit potent biofilm-eradication activity against a variety of medically important pathogens, including P. aeruginosa, uropathogenic E. coli, and S. aureus. In Minimal Biofilm Eradication Concentration (MBEC) assays nitroxide functionalised antibiotics were 64-fold more potent against S. aureus biofilms, and at least 2-fold more potent against uropathogenic E. coli biofilms than the parent antibiotic ciprofloxacin. Conclusions: Currently, antibiotics are often entirely ineffective against biofilm infections. Nitroxide functionalised antibiotics represent a promising new strategy, which could circumvent the resistance of Gram-positive and Gram-negative biofilms to conventional treatments.

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Specific Electromagnetic Effects of Microwave Radiation on Escherichia coli

Applied and Environmental Microbiology ◽

10.1128/aem.01899-10 ◽

2011 ◽

Vol 77 (9) ◽

pp. 3017-3022 ◽

Cited By ~ 44

Author(s):

Yury Shamis ◽

Alex Taube ◽

Natasa Mitik-Dineva ◽

Rodney Croft ◽

Russell J. Crawford ◽

...

Keyword(s):

Escherichia Coli ◽

Cell Membrane ◽

Cell Morphology ◽

Laser Scanning ◽

Simulation Software ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Bacterial Cells ◽

Content Type ◽

E Coli

ABSTRACTThe present study investigated the effects of microwave (MW) radiation applied under a sublethal temperature onEscherichia coli. The experiments were conducted at a frequency of 18 GHz and at a temperature below 40°C to avoid the thermal degradation of bacterial cells during exposure. The absorbed power was calculated to be 1,500 kW/m3, and the electric field was determined to be 300 V/m. Both values were theoretically confirmed using CST Microwave Studio 3D Electromagnetic Simulation Software. As a negative control,E. colicells were also thermally heated to temperatures up to 40°C using Peltier plate heating. Scanning electron microscopy (SEM) analysis performed immediately after MW exposure revealed that theE. colicells exhibited a cell morphology significantly different from that of the negative controls. This MW effect, however, appeared to be temporary, as following a further 10-min elapsed period, the cell morphology appeared to revert to a state that was identical to that of the untreated controls. Confocal laser scanning microscopy (CLSM) revealed that fluorescein isothiocyanate (FITC)-conjugated dextran (150 kDa) was taken up by the MW-treated cells, suggesting that pores had formed within the cell membrane. Cell viability experiments revealed that the MW treatment was not bactericidal, since 88% of the cells were recovered after radiation. It is proposed that one of the effects of exposingE. colicells to MW radiation under sublethal temperature conditions is that the cell surface undergoes a modification that is electrokinetic in nature, resulting in a reversible MW-induced poration of the cell membrane.

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Restitution of single-cell defects in the mouse colon epithelium differs from that of cultured cells

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00470.2005 ◽

2006 ◽

Vol 290 (6) ◽

pp. R1496-R1507 ◽

Cited By ~ 21

Author(s):

D. Günzel ◽

P. Florian ◽

J. F. Richter ◽

H. Troeger ◽

J. D. Schulzke ◽

...

Keyword(s):

Single Cell ◽

Laser Scanning ◽

Pathogenic Bacteria ◽

Cultured Cells ◽

Healing Process ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Rapid Repair ◽

E Coli ◽

Tnf Α

Integrity of colon epithelium is of crucial importance and, as small defects occur constantly, rapid repair (restitution) is essential. To investigate the mechanism of restitution, single-cell lesions were induced in mouse colonic surface epithelia by iontophoretic injection of Ca2+. Closure of the resulting defects was monitored using confocal laser scanning microscopy (CLSM), and functional sealing by electrophysiological techniques. Restitution was evaluated as the time constant τ of the exponential decrease in conductance of an induced leak and amounted to 0.28 min under control conditions. After 4 min, the leak was completely sealed. Repair was thus considerably faster than in previously investigated HT-29/B6 cells (τ = 5.73 min). As in cultured cells, cytochalasin D delayed restitution in native colon epithelia (τ = 0.69 min), indicating the involvement of actin in the healing process; however, no accumulation of actin surrounding the lesion was detected. Long-term incubation of epithelia with IFN-γ alone or in combination with TNF-α increased τ to 0.49 and 0.59 min, respectively. In contrast to cultured cells, TNF-α alone did not affect restitution. A brief (<10 min) exposure to the sterile filtered supernatant of hemolytic E. coli O4 cultures did not affect the morphology of the epithelium, but delayed restitution. In CLSM studies, defects were still clearly visible 4 min after the onset of lesion induction. The supernatant of a nonhemolytic E. coli O4 mutant did not exhibit this effect. In conclusion, single-cell defects in native colon cause functional leaks that seal faster than in cell cultures. Proinflammatory cytokines and pathogenic bacteria delay restitution. This suggests a key role of very small lesions at the onset of pathogenic processes in the intestine.

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Effects of lipid emulsions on the formation of Escherichia coli–Candida albicans mixed-species biofilms on PVC

Scientific Reports ◽

10.1038/s41598-021-96385-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Shanshan Li ◽

Wanshi Duan ◽

Yujie Lei ◽

Zhonghui Wang ◽

Chaojiang Fu ◽

...

Keyword(s):

Escherichia Coli ◽

Candida Albicans ◽

Laser Scanning ◽

Bloodstream Infections ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Lipid Emulsions ◽

Mixed Species ◽

E Coli ◽

Increased Risk

AbstractPatients receiving lipid emulsions are at increased risk of contracting catheter-related bloodstream infections (CRBSIs) in the clinic. More than 15% of CRBSIs are polymicrobial. The objective of this study was to explore the effects of lipid emulsions on the formation of Escherichia coli (E. coli)–Candida albicans (C. albicans) mixed-species biofilms (BFs) on polyvinyl chloride (PVC) surfaces and the underlying mechanism. Mixed-species BFs were produced by coculturing E. coli and C. albicans with PVC in various concentrations of lipid emulsions. Crystal violet staining and XTT assays were performed to test the mixed-species BF biomass and the viability of microbes in the BFs. The microstructures of the BFs were observed by an approach that combined confocal laser scanning microscopy, fluorescence in situ hybridization, and scanning electron microscopy. The study found that lipid emulsions could promote the formation of E. coli–C. albicans mixed-species BFs, especially with 10% lipid emulsions. The mechanism by which lipid emulsions promote mixed-species BF formation may involve significant upregulation of the expression of the flhDC, iha, HTA1, and HWP1 genes, which are associated with bacterial motility, adhesion, and BF formation. The results derived from this study necessitate strict aseptic precautions when handling lipid emulsions and avoiding the use of high concentrations of lipid emulsions for as long as possible.

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