scholarly journals Organo-Selenium-Containing Polyester Bandage Inhibits Bacterial Biofilm Growth on the Bandage and in the Wound

Biomedicines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 62
Author(s):  
Phat Tran ◽  
Tyler Enos ◽  
Keaton Luth ◽  
Abdul Hamood ◽  
Coby Ray ◽  
...  
Keyword(s):  
Wound Infection ◽  
Wound Dressing ◽  
Laser Scanning ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Strains ◽  
Biofilm Growth ◽  
Biofilm Model

The dressing material of a wound plays a key role since bacteria can live in the bandage and keep re-infecting the wound, thus a bandage is needed that blocks biofilm in the bandage. Using an in vivo wound biofilm model, we examined the effectiveness of an organo-selenium (OS)-coated polyester dressing to inhibit the growth of bacteria in a wound. Staphylococcus aureus (as well as MRSA, Methicillin resistant Staph aureus), Stenotrophomonas maltophilia, Enterococcus faecalis, Staphylococcus epidermidis, and Pseudomonas aeruginosa were chosen for the wound infection study. All the bacteria were enumerated in the wound dressing and in the wound tissue under the dressing. Using colony-forming unit (CFU) assays, over 7 logs of inhibition (100%) was found for all the bacterial strains on the material of the OS-coated wound dressing and in the tissue under that dressing. Confocal laser scanning microscopy along with IVIS spectrum in vivo imaging confirmed the CFU results. Thus, the dressing acts as a reservoir for a biofilm, which causes wound infection. The same results were obtained after soaking the dressing in PBS at 37 °C for three months before use. These results suggest that an OS coating on polyester dressing is both effective and durable in blocking wound infection.

scholarly journals The Interaction of N-Acetylcysteine and Serum Transferrin Promotes Bacterial Biofilm Formation

2018 ◽  
Vol 45 (4) ◽  
pp. 1399-1409 ◽  
Author(s):  
Supeng Yin ◽  
Bei Jiang ◽  
Guangtao Huang ◽  
Yulong Zhang ◽  
Bo You ◽  
...  
Keyword(s):  
Human Serum ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Serum Proteins ◽  
Venous Catheter ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Strains

Background/Aims: N-acetylcysteine (NAC) is a novel and promising agent with activity against bacterial biofilms. Human serum also inhibits biofilm formation by some bacteria. We tested whether the combination of NAC and human serum offers greater anti-biofilm activity than either agent alone. Methods: Microtiter plate assays and confocal laser scanning microscopy were used to evaluate bacterial biofilm formation in the presence of NAC and human serum. qPCR was used to examine expression of selected biofilm-associated genes. Extracellular matrix (ECM) was observed by transmission electron microscopy. The antioxidants GSH or ascorbic acid were used to replace NAC, and human transferrin, lactoferrin, or bovine serum albumin were used to replace serum proteins in biofilm formation assays. A rat central venous catheter model was developed to evaluate the effect of NAC on biofilm formation in vivo. Results: NAC and serum together increased biofilm formation by seven different bacterial strains. In Staphylococcus aureus, expression of genes for some global regulators and for genes in the ica-dependent pathway increased markedly. In Pseudomonas aeruginosa, transcription of las, the PQS quorum sensing (QS) systems, and the two-component system GacS/GacA increased significantly. ECM production by S. aureus and P. aeruginosa was also enhanced. The potentiation of biofilm formation is due mainly to interaction between NAC and transferrin. Intravenous administration of NAC increased colonization by S. aureus and P. aeruginosa on implanted catheters. Conclusions: NAC used intravenously or in the presence of blood increases bacterial biofilm formation rather than inhibits it.

scholarly journals Effect of Novel Antibacterial Composites on Bacterial Biofilms

2020 ◽  
Vol 11 (3) ◽  
pp. 55 ◽  
Author(s):  
Rayan B. Yaghmoor ◽  
Wendy Xia ◽  
Paul Ashley ◽  
Elaine Allan ◽  
Anne M. Young
Keyword(s):  
Laser Scanning ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Surface Layers ◽  
Composite Surface ◽  
Biofilm Thickness ◽  
Diffusion Controlled ◽  
Restoration Failure

Continuing cariogenic bacterial growth demineralizing dentine beneath a composite filling is the most common cause of tooth restoration failure. Novel composites with antibacterial polylysine (PLS) (0, 4, 6, or 8 wt%) in its filler phase were therefore produced. Remineralising monocalcium phosphate was also included at double the PLS weight. Antibacterial studies involved set composite disc placement in 1% sucrose-supplemented broth containing Streptococcus mutans (UA159). Relative surface bacterial biofilm mass (n = 4) after 24 h was determined by crystal violet-binding. Live/dead bacteria and biofilm thickness (n = 3) were assessed using confocal laser scanning microscopy (CLSM). To understand results and model possible in vivo benefits, cumulative PLS release from discs into water (n = 3) was determined by a ninhydrin assay. Results showed biofilm mass and thickness decreased linearly by 28% and 33%, respectively, upon increasing PLS from 0% to 8%. With 4, 6, and 8 wt% PLS, respectively, biofilm dead bacterial percentages and PLS release at 24 h were 20%, 60%, and 80% and 85, 163, and 241 μg/disc. Furthermore, initial PLS release was proportional to the square root of time and levelled after 1, 2, and 3 months at 13%, 28%, and 42%. This suggested diffusion controlled release from water-exposed composite surface layers of 65, 140, and 210 μm thickness, respectively. In conclusion, increasing PLS release initially in any gaps under the restoration to kill residual bacteria or longer-term following composite/tooth interface damage might help prevent recurrent caries.

scholarly journals Sinonasal Stent Coated with Slow-Release Varnish of Chlorhexidine Has Sustained Protection against Bacterial Biofilm Growth in the Sinonasal Cavity: An In Vitro Study

Pharmaceutics ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1783
Author(s):  
Alessandra Cataldo Cataldo Russomando ◽  
Ronit Vogt Vogt Sionov ◽  
Michael Friedman ◽  
Irith Gati ◽  
Ron Eliashar ◽  
...  
Keyword(s):  
Bacterial Growth ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Disc Diffusion ◽  
Biofilm Growth ◽  
Disc Diffusion Assay ◽  
Diffusion Assay

The aim of the study was to develop a sustained-release varnish (SRV) containing chlorhexidine (CHX) for sinonasal stents (SNS) to reduce bacterial growth and biofilm formation in the sinonasal cavity. Segments of SNS were coated with SRV-CHX or SRV-placebo and exposed daily to bacterial cultures of Staphylococcus aureus subsp. aureus ATCC 25923 or Pseudomonas aeruginosa ATCC HER-1018 (PAO1). Anti-bacterial effects were assessed by disc diffusion assay and planktonic-based activity assay. Biofilm formation on the coated stents was visualized by confocal laser scanning microscopy (CLSM) and high-resolution scanning electron microscopy (HR-SEM). The metabolic activity of the biofilms was determined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) method. Disc diffusion assay showed that SRV-CHX-coated SNS segments inhibited bacterial growth of S. aureus subsp. aureus ATCC 25923 for 26 days and P. aeruginosa ATCC HER-1018 for 19 days. CHX was released from coated SNS segments in a pH 6 medium up to 30 days, resulting in growth inhibition of S. aureus subsp. aureus ATCC 25923 for 22 days and P. aeruginosa ATCC HER-1018 for 24 days. The MTT assay showed a reduction of biofilm growth on the coated SNS by 69% for S. aureus subsp. aureus ATCC 25923 and 40% for P. aeruginosa ATCC HER-1018 compared to the placebo stent after repeated exposure to planktonic growing bacteria. CLSM and HR-SEM showed a significant reduction of biofilm formation on the SRV-CHX-coated SNS segments. Coating of SNS with SRV-CHX maintains a sustained delivery of CHX, providing an inhibitory effect on the bacterial growth of S. aureus subsp. aureus ATCC 25923 and P. aeruginosa ATCC HER-1018 for approximately 3 weeks.

scholarly journals The role of surface adhesion on the macroscopic wrinkling of biofilms

2021 ◽  
Author(s):  
Steffen Geisel ◽  
Eleonora Secchi ◽  
Jan Vermant
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Microfluidic Channels ◽  
Channel Networks ◽  
Biofilm Growth ◽  
And Control

Biofilms, bacterial communities of cells encased by a self-produced matrix, exhibit a variety of three-dimensional structures. Specifically, channel networks formed within the bulk of the biofilm have been identified to play an important role in the colonies viability by promoting the transport of nutrients and chemicals. Here, we study channel formation and focus on the role of the adhesion of the biofilm matrix to the substrate in Pseudomonas aeruginosa biofilms grown under constant flow in microfluidic channels. We perform phase contrast and confocal laser scanning microscopy to examine the development of the biofilm structure as a function of the substrates surface energy. The formation of the wrinkles and folds is triggered by a mechanical buckling instability, controlled by biofilm growth rate and the film's adhesion to the substrate. The three-dimensional folding gives rise to hollow channels that rapidly increase the overall volume occupied by the biofilm and facilitate bacterial movement inside them. The experiments and analysis on mechanical instabilities for the relevant case of a bacterial biofilm grown during flow enable us to predict and control the biofilm morphology.

Vacuoles Induced in Mammalian Cells by Helicobacter Cytotoxin are Acidic Organelles

1990 ◽  
Vol 48 (3) ◽  
pp. 168-169
Author(s):  
M. H. Chestnut ◽  
C. E. Catrenich
Keyword(s):  
Acridine Orange ◽  
Mammalian Cells ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Ulcer Disease ◽  
Gastroduodenal Disease ◽  
H Pylori

Helicobacter pylori is a non-invasive, Gram-negative spiral bacterium first identified in 1983, and subsequently implicated in the pathogenesis of gastroduodenal disease including gastritis and peptic ulcer disease. Cytotoxic activity, manifested by intracytoplasmic vacuolation of mammalian cells in vitro, was identified in 55% of H. pylori strains examined. The vacuoles increase in number and size during extended incubation, resulting in vacuolar and cellular degeneration after 24 h to 48 h. Vacuolation of gastric epithelial cells is also observed in vivo during infection by H. pylori. A high molecular weight, heat labile protein is believed to be responsible for vacuolation and to significantly contribute to the development of gastroduodenal disease in humans. The mechanism by which the cytotoxin exerts its effect is unknown, as is the intracellular origin of the vacuolar membrane and contents. Acridine orange is a membrane-permeant weak base that initially accumulates in low-pH compartments. We have used acridine orange accumulation in conjunction with confocal laser scanning microscopy of toxin-treated cells to begin probing the nature and origin of these vacuoles.

scholarly journals Targeted Liposomal Chemotherapies to Treat Triple-Negative Breast Cancer

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3749
Author(s):  
Yingnan Si ◽  
Ya Zhang ◽  
Hanh Giai Ngo ◽  
Jia-Shiung Guan ◽  
Kai Chen ◽  
...  
Keyword(s):  
Targeted Delivery ◽  
Laser Scanning ◽  
Triple Negative ◽  
Imaging System ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Surface Binding ◽  
Synthesis Inhibitor ◽  
Tnbc Cell

Triple-negative breast cancers (TNBCs) are highly aggressive and recurrent. Standard cytotoxic chemotherapies are currently the main treatment options, but their clinical efficacies are limited and patients usually suffer from severe side effects. The goal of this study was to develop and evaluate targeted liposomes-delivered combined chemotherapies to treat TNBCs. Specifically, the IC50 values of the microtubule polymerization inhibitor mertansine (DM1), mitotic spindle assembly defecting taxane (paclitaxel, PTX), DNA synthesis inhibitor gemcitabine (GC), and DNA damage inducer doxorubicin (AC) were tested in both TNBC MDA-MB-231 and MDA-MB-468 cells. Then we constructed the anti-epidermal growth factor receptor (EGFR) monoclonal antibody (mAb) tagged liposomes and confirmed its TNBC cell surface binding using flow cytometry, internalization with confocal laser scanning microscopy, and TNBC xenograft targeting in NSG female mice using In Vivo Imaging System. The safe dosage of anti-EGFR liposomal chemotherapies, i.e., <20% body weight change, was identified. Finally, the in vivo anti-tumor efficacy studies in TNBC cell line-derived xenograft and patient-derived xenograft models revealed that the targeted delivery of chemotherapies (mertansine and gemcitabine) can effectively inhibit tumor growth. This study demonstrated that the targeted liposomes enable the new formulations of combined therapies that improve anti-TNBC efficacy.

scholarly journals Degradation of Drug Delivery Nanocarriers and Payload Release: A Review of Physical Methods for Tracing Nanocarrier Biological Fate

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 770
Author(s):  
Patrick M. Perrigue ◽  
Richard A. Murray ◽  
Angelika Mielcarek ◽  
Agata Henschke ◽  
Sergio E. Moya
Keyword(s):  
Drug Delivery ◽  
Laser Scanning ◽  
Single Photon ◽  
Photon Emission ◽  
Correlation Spectroscopy ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Emission Computed Tomography ◽  
Systemic Delivery

Nanoformulations offer multiple advantages over conventional drug delivery, enhancing solubility, biocompatibility, and bioavailability of drugs. Nanocarriers can be engineered with targeting ligands for reaching specific tissue or cells, thus reducing the side effects of payloads. Following systemic delivery, nanocarriers must deliver encapsulated drugs, usually through nanocarrier degradation. A premature degradation, or the loss of the nanocarrier coating, may prevent the drug’s delivery to the targeted tissue. Despite their importance, stability and degradation of nanocarriers in biological environments are largely not studied in the literature. Here we review techniques for tracing the fate of nanocarriers, focusing on nanocarrier degradation and drug release both intracellularly and in vivo. Intracellularly, we will discuss different fluorescence techniques: confocal laser scanning microscopy, fluorescence correlation spectroscopy, lifetime imaging, flow cytometry, etc. We also consider confocal Raman microscopy as a label-free technique to trace colocalization of nanocarriers and drugs. In vivo we will consider fluorescence and nuclear imaging for tracing nanocarriers. Positron emission tomography and single-photon emission computed tomography are used for a quantitative assessment of nanocarrier and payload biodistribution. Strategies for dual radiolabelling of the nanocarriers and the payload for tracing carrier degradation, as well as the efficacy of the payload delivery in vivo, are also discussed.

Probing Enhanced Cytochrome P450 2B1/2 Activity in Rat Hepatocyte Spheroids through Confocal Laser Scanning Microscopy

2001 ◽  
Vol 10 (3) ◽  
pp. 329-342 ◽  
Author(s):  
Emmanouhl S. Tzanakakis ◽  
Chang-Chun Hsiao ◽  
Taku Matsushita ◽  
Rory P. Remmel ◽  
Wei-Shou Hu
Keyword(s):  
Cytochrome P450 ◽  
Confocal Laser Scanning Microscopy ◽  
Laser Scanning ◽  
Constitutive Expression ◽  
Rat Hepatocytes ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Scanning Microscopy ◽  
Confocal Laser

Cytochrome P450 (CYP450) enzymes are essential for xenobiotic metabolism. Although CYP450s are found in many tissues, CYP2B1/2 are primarily expressed in the rat liver. The constitutive expression in vivo of CYP2B1/2 is low but it is induced in the presence of various drugs such as phenobarbital (PB). In this study, CYP2B1/2 activity in cultured hepatocytes was assessed in situ with the introduction of a fluorogenic sub-strate, pentoxyresorufin. The product of 7-pentoxyresorufin-O-dealkylation (PROD), which is catalyzed specifically by CYP2B1/2, was detected using confocal laser scanning microscopy (CLSM). Primary hepatocytes cultured as monolayers on collagen-coated surfaces exhibited background PROD activity and minimal PB inducibility after 4 days in culture. In contrast, rat hepatocytes organized in compacted aggregates, or spheroids, exhibited higher levels of PROD activity and retained their ability for PB induction. The results from the CLSM analysis were verified by RT-PCR and Western immunoblotting analysis. Furthermore, CLSM in conjunction with image processing techniques and three-dimensional reconstruction revealed the localization of enhanced PROD activity in the center of spheroids. The results support the use of CLSM as a powerful tool for investigating CYP2B1/2 activity in cultured rat hepatocytes.

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