Nitric Oxide-Releasing Alginates.
Ontology highlight
ABSTRACT:
SUBMITTER: Ahonen MJR
PROVIDER: S-EPMC6759059 | biostudies-literature | 2018 Apr
REPOSITORIES: biostudies-literature
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Project description:The excessive production of thick, viscous mucus in severe respiratory diseases leads to obstruction of the airways and provides a suitable environment for the colonization of pathogenic bacteria. The effect of nitric oxide (NO)-releasing alginates with varying NO release kinetics on the viscoelastic properties of human bronchial epithelial (HBE) mucus was evaluated as a function of the NO-release kinetics using parallel plate rheology. Low molecular weight (~5 kDa) alginates with high NO flux (~4000 ppb/mg) and sustained release (half-life ~0.3 h) proved to be most effective in reducing both mucus elasticity and viscosity (?60% reduction for both). The efficacy of the NO-releasing alginates was shown to be dose-dependent, with high concentrations of NO-releasing alginates (~80 mg•mL-1) resulting in greater reduction of the viscosity and elasticity of the mucus samples. Greater reduction in mucus rheology was also achieved with NO-releasing alginates at lower concentrations when compared to both NO-releasing chitosan, a similarly biocompatible cationic polymer, and N-acetyl cysteine (NAC), a conventional mucolytic agent.
| S-EPMC7164775 | biostudies-literature
Project description:Colonization of the lungs by biofilm-forming pathogens is a major cause of mortality in cystic fibrosis (CF). In CF patients, these pathogens are difficult to treat due to the additional protection provided by both the biofilm exopolysaccharide matrix and thick, viscous mucus. The antibiofilm efficacy of nitric oxide (NO)-releasing alginates was evaluated against Pseudomonas aeruginosa, Burkholderia cepacia, Staphylococcus aureus, and methicillin-resistant S. aureus biofilms in both aerobic and anaerobic environments. Varying the amine precursor grafted onto alginate oligosaccharides imparted tunable NO storage (?0.1-0.3 ?mol/mg) and release kinetics (?4-40 min half-lives) in the artificial sputum media used for biofilm testing. The NO-releasing alginates were highly antibacterial against the four CF-relevant pathogens, achieving a 5-log reduction in biofilm viability after 24 h of treatment, with biocidal efficacy dependent on NO-release kinetics. Aerobic biofilms required greater starting NO doses to achieve killing relative to the anaerobic biofilms. Relative to tobramycin (the minimum concentration of antibacterial agent required to achieve a 5-log reduction in viability after 24 h, MBEC24h, of ?2000 ?g/mL) and vancomycin (MBEC24h ? 1000 ?g/mL), the NO-releasing alginates proved to be more effective (NO dose ? 520 ?g/mL) regardless of growth conditions.
| S-EPMC6773255 | biostudies-literature
Project description:A series of secondary amine-modified cyclodextrin (CD) derivatives was synthesized with diverse exterior terminal groups (i.e., hydroxyl, methyl, methoxyl, and primary amine). Subsequent reaction with nitric oxide (NO) gas under alkaline conditions yielded N-diazeniumdiolate-modified CD derivatives. Adjustable NO payloads (0.6-2.4 ?mol/mg) and release half-lives (0.7-4.2 h) were achieved by regulating both the amount of secondary amine precursors and the functional groups around the NO donors. The bactericidal action of these NO-releasing cyclodextrin derivatives was evaluated against Pseudomonas aeruginosa, a Gram-negative pathogen, with antibacterial activity proving dependent on both the NO payload and exterior modification. Materials containing a high density of NO donors or primary amines exhibited the greatest ability to eradicate P. aeruginosa. Of the materials prepared, only the primary amine-terminated heptasubstituted CD derivatives exhibited toxicity against mammalian L929 mouse fibroblast cells. The NO donor-modified CD was also capable of delivering promethazine, a hydrophobic drug, thus demonstrating potential as a dual-drug-releasing therapeutic.
| S-EPMC6790977 | biostudies-literature
Project description:In this study, the ability of porous silicon nanoparticles (PSi NPs) to entrap and deliver nitric oxide (NO) as an effective antibacterial agent is tested against different Gram-positive and Gram-negative bacteria. NO was entrapped inside PSi NPs functionalized by means of the thermal hydrocarbonization (THC) process. Subsequent reduction of nitrite in the presence of d-glucose led to the production of large NO payloads without reducing the biocompatibility of the PSi NPs with mammalian cells. The resulting PSi NPs demonstrated sustained release of NO and showed remarkable antibacterial efficiency and anti-biofilm-forming properties. These results will set the stage to develop antimicrobial nanoparticle formulations for applications in chronic wound treatment.
| S-EPMC4109794 | biostudies-literature
Project description:The preparation of electrospun polymer microfibers with nitric oxide (NO)-release capabilities is described. Polymer solutions containing disodium 1-[2-(carboxylato)pyrrolidin-1-yl]diazen-1-ium-1,2-diolate (PROLI/NO), a low-molecular-weight NO donor, were electrospun to generate fibers ranging from 100-3000 nm in diameter capable of releasing NO upon immersion in aqueous solutions under physiological conditions (pH 7.4, 37 °C), with kinetics depending on polymer composition and fiber diameter. The NO release half-life for PROLI/NO-doped electrospun fibers was 2-200 times longer than that of PROLI/NO alone. The influence of polymer concentration, applied voltage, capillary diameter, solution conductivity, flow rate, and additives on fiber properties are reported and discussed with respect to potential applications.
| S-EPMC3045468 | biostudies-literature
Project description:Wild-type Campylobacter jejuni NCTC11168 was grown in 2 homemade, parallel chemostats. Cells were grown in 125 ml volumes of Mueller-Hinton Broth where the growth rate was controlled by the dilution rate (0.1 h-1). A gas mix of 80% nitrogen, 10% carbon dioxide and 10% oxygen was pumped into the head-space of the vessels at a rate of 0.25 l/min to obtain a microaerobic environment and the culture was maintained at 42 ºC via a water jacket. Cells were grown as above until steady-state had been reached. At steady-state one of the cultures was exposed to 10 uM NOC-5 & -7 (final concentration) for a period of 10 min. Samples of both the control and stressed cultures were harvested into phenol/ethanol to stabilize the RNA and total RNA was purified using Qiagen’s RNeasy Mini kit (as recommended by the suppliers) prior to use in microarray analysis. Equal quantities of RNA from control and GSNO-supplemented cultures were labelled using nucleotide analogues of dCTP containing either Cy3 or Cy5 fluorescent dyes. The average signal intensity and local background correction were obtained using a commercially available software package from Biodiscovery, Inc (Imagene, version 4.0 and GeneSight, version 4). The mean values from each channel were log2 transformed and normalised using the Lowess method to remove intensity-dependent effects in the log2(ratios) values. The Cy3/Cy5 fluorescent ratios were calculated from the normalized values. Keywords: Stress-response of a cgb mutant to NOC-5 & -7
2007-12-31 | GSE5400 | GEO
Project description:Wild-type Campylobacter jejuni NCTC11168 was grown in 2 homemade, parallel chemostats. Cells were grown in 125 ml volumes of Mueller-Hinton Broth where the growth rate was controlled by the dilution rate (0.1 h-1). A gas mix of 80% nitrogen, 10% carbon dioxide and 10% oxygen was pumped into the head-space of the vessels at a rate of 0.25 l/min to obtain a microaerobic environment and the culture was maintained at 42 ºC via a water jacket. Cells were grown as above until steady-state had been reached. At steady-state one of the cultures was exposed to 10 uM NOC-5 & -7 (final concentration) for a period of 10 min. Samples of both the control and stressed cultures were harvested into phenol/ethanol to stabilize the RNA and total RNA was purified using Qiagenâ??s RNeasy Mini kit (as recommended by the suppliers) prior to use in microarray analysis. Equal quantities of RNA from control and GSNO-supplemented cultures were labelled using nucleotide analogues of dCTP containing either Cy3 or Cy5 fluorescent dyes. The average signal intensity and local background correction were obtained using a commercially available software package from Biodiscovery, Inc (Imagene, version 4.0 and GeneSight, version 4). The mean values from each channel were log2 transformed and normalised using the Lowess method to remove intensity-dependent effects in the log2(ratios) values. The Cy3/Cy5 fluorescent ratios were calculated from the normalized values. C. jejuni NCTC11168 was grown in two parallel custom-built chemostats based on Sigma Proculture Dynalift spinner flasks with a working volume of 125 ml, and the dilution rate (which at steady state is equal to the specific growth rate) of 0.1 h-1. A gas mix of 10% O2, 10% CO2 and 80% N2 was passed into the head space of the culture vessel at a rate of 0.25 l min-1 to obtain a microaerobic atmosphere, and silicone water jackets maintained the temperature at 42 ºC. The flasks were placed on KMO 2 basic IKA-Werke stirrers (arbitrary setting, 260; Scientific Laboratory Supplies), which gaveeffective transfer of O2 from the gaseous atmosphere to the culture by virtue of a stable vortex. A fresh overflow sample was used to check the pH at the time of harvest (which was consistently between 6.6 and 7) and to ensure that there was no contamination by plating a 20 μl sample onto both nutrient agar plates incubated at 37 °C at atmospheric oxygen, and Mueller-Hinton plates incubated at 42 °C in the microaerophilic work station. When staedy-state was reached, as verified by collecting at least 5 culture volumes, NOC-5 & -7 (final concentration 10 uM) was added to one culture. After a further 10 min the 125 ml volume was separated into 3 equal volumes and each was mixed immediately on ice with 3.56 ml 100% ethanol and 185 ml phenol to stabilize the RNA. The cells were subsequently harvested by centrifugation. Total RNA was purified by using a Qiagen RNeasy Mini kit as recommended by the supplier. cDNA synthesis was carried out using 12 µg of starting material, which was primed with 9 µg of pd(N)6 random hexamers (Amersham Biosciences). Reaction mixtures (20 µl) containing 0.5 mM ATP, 0.5 mM TTP, 0.5 mM GTP, 0.2 mM CTP, and 1 mM Cy3- or 1 mM Cy5-dCTP were incubated for 2 h at 42 °C with 200 U of Superscript II RNase H reverse transcriptase (Invitrogen). Following synthesis, cDNA was purified by using a PCR purification kit (Qiagen) to remove the unincorporated deoxynucloside triphosphates, fluorescent dye, and primers. Equal volumes of cDNA were combined and evaporated to near dryness with an SPD121P Speed Vac (Thermon Savant). For hybridisation to the microarray slides, cDNA was resuspended in an appropriate volume of salt-based hybridization buffer (provided by Ocimum Biosolutions). Prior to addition to the slides, cDNA samples were heated to 95 °C for 3 min, and then placed on ice for no more than 3 min. The slides were placed in MWG Biotech hybridization chambers and incubated for 16 to 24 h in a shaking water bath at 110 rpm and 42 °C. Following incubation , the slides were washed sequentially for 5 min in 2x SSC-1 % sodium dodecyl sulphate, 1x SSC, 0.5x SSC and 0.1x SSC at 37 °C with gentle agitation (1x SSC is 0.15 M NaCl plus 0.015 M sodium citrate). The slides were dried by centrifugation at 254 xg for 5 min and subsequently scanned with an Affymetrix 428 scanner. The average signal intensity and local background correction were obtained by using commercially available software from Biodiscovery, Inc. (Imagine version 4.0, and Genesight, version 3.5). The mean values from each channel were log2 transformed and normalized by using the subtract-by-mean method to remove intensity-dependent effects in the log2 (ratio) values. The Cy3/Cy5 fluorescence ratios were calculated from the normalized values. Biological experiments (i.e. chemostat growth with and without 0.25 mM GSNO addition) were carried out three times and a dye swap was performed for two of the three experiments which provided two technical repeats, one each for two of the three biological repeats. Data from the independent experiments were combined. Genes that were differentially expressed â?¥ twofold and displayed and P value of â?¤ 0.05 (as determined by a t test) were defined as being statistically significantly differentially transcribed.
2010-06-30 | E-GEOD-5400 | biostudies-arrayexpress
Project description:In this study, fast and slow nitric oxide (NO)-releasing liposomes (half-lives of 2.5 and >72 h, respectively) were prepared by encapsulation of N-propyl-1,3-propanediamine/NO (PAPA/NO) and diethylenetriamine/NO (DETA/NO), respectively, via reverse phase evaporation. The anticancer activity of the otherwise equivalent fast and slow NO-releasing systems was evaluated against several distinct pancreatic, colorectal, and breast cancer cell lines. The anticancer assays (via cytotoxicity) over 72 h revealed that the slower NO-releasing liposomes consistently required lower NO payloads (LD50 <3 μg/mL) relative to the fast NO-release system (LD50 >6 μg/mL) to elicit cytotoxicity. The mechanism of intracellular NO build-up in cancer cells was studied using confocal fluorescence microscopy and flow cytometry, the results of which indicated that a more gradual NO accumulation was characteristic of the slow NO-release system. Protein expression via Western blot analysis revealed that slower NO release resulted in more necrotic/apoptotic cells, while faster release reduced the number of mitotic cells to a greater extent. Overall, these studies demonstrate the potential of NO-releasing liposomes for anticancer therapy and highlight the significance of release kinetics (and NO payloads) required to induce cell death.
| S-EPMC6366668 | biostudies-literature
Project description:The antibacterial activity of a series of nitric oxide (NO)-releasing poly(propylene imine) (PPI) dendrimers was evaluated against both Gram-positive and Gram-negative pathogenic bacteria, including methicillin-resistant Staphylococcus aureus . A direct comparison of the bactericidal efficacy between NO-releasing and control PPI dendrimers (i.e., non-NO-releasing) revealed both enhanced biocidal action of NO-releasing dendrimers and reduced toxicity against mammalian fibroblast cells. Antibacterial activity for the NO donor-functionalized PPI dendrimers was shown to be a function of both dendrimer size (molecular weight) and exterior functionality. In addition to minimal toxicity against fibroblasts, NO-releasing PPI dendrimers modified with styrene oxide exhibited the greatest biocidal activity (≥99.999% killing) against all bacterial strains tested. The N-diazeniumdiolate NO donor-functionalized PPI dendrimers presented in this study hold promise as effective NO-based therapeutics for combating bacterial infections.
| S-EPMC3482834 | biostudies-literature
Project description:Hyperbranched polyamidoamines (h-PAMAM) were prepared using a one-pot reaction to have similar molecular weight to third generation PAMAM (G3-PAMAM) dendrimers, and then functionalized with N-diazeniumdiolate nitric oxide (NO) donors. A wide range of NO storage capacities (?1-2.50 ?mol mg-1) and NO-release kinetics (t1/2 ?30-80 min) were achieved by changing the extent of propylene oxide (PO) modification. The therapeutic potential of these materials was evaluated by studying their antibacterial activities and toxicity against common dental pathogens and human gingival fibroblast cells, respectively. Our results indicate that the combination of NO release and PO modification is necessary to yield h-PAMAM materials with efficient bactericidal action without eliciting unwarranted cytotoxicity. Of importance, NO-releasing PO-modified h-PAMAM polymers exhibited comparable biological properties (i.e., antibacterial action and cytotoxicity) to defect-free G3-PAMAM dendrimers, but at a substantially lower synthetic burden.
| S-EPMC6773256 | biostudies-literature