| 1. |
- Barbero, David, et al.
(författare)
-
Carbon nanotube networks : nano-engineering of SWNT networks for enhanced charge transport at ultralow nanotube loading
- 2014
-
Ingår i: Advanced Materials. - : Wiley-VCH Verlagsgesellschaft. - 0935-9648 .- 1521-4095. ; 26:19, s. 3164-
-
Tidskriftsartikel (refereegranskat)abstract
- Arrays of nano-engineered carbon nanotube networks embedded in nanoscale polymer structures enable highly efficient charge transport as demonstrated by D. R. Barbero and co-workers on page 3111. An increase in charge transport by several orders of magnitude is recorded at low nanotube loading compared to traditional random networks in either insulating (polystyrene) or semiconducting (polythiophene) polymers. These novel networks are expected to enhance the performance of next generation hybrid and carbon based photovoltaic devices.
|
|
| 2. |
- Barbero, David, et al.
(författare)
-
Nano-engineering of SWNT networks for enhanced charge transport at ultralow nanotube loading
- 2014
-
Ingår i: Advanced Materials. - : John Wiley & Sons. - 0935-9648 .- 1521-4095. ; 26:19, s. 3111-3117
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a simple and controllable method to form periodic arrays of highly conductive nano-engineered single wall carbon nanotube networks from solution. These networks increase the conductivity of a polymer composite by as much as eight orders of magnitude compared to a traditional random network. These nano-engineered networks are demonstrated in both polystyrene and polythiophene polymers.
|
|
| 3. |
- Barzegar, Hamid R., et al.
(författare)
-
Simple Dip-Coating Process for the Synthesis of Small Diameter Single-Walled Carbon Nanotubes-Effect of Catalyst Composition and Catalyst Particle Size on Chirality and Diameter
- 2012
-
Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 116:22, s. 12232-12239
-
Tidskriftsartikel (refereegranskat)abstract
- We report on a dip-coating method to prepare catalyst particles (mixture of iron and cobalt) with a controlled diameter distribution on silicon wafer substrates by changing the solution's concentration and withdrawal velocity. The size and distribution of the prepared catalyst particles were analyzed by atomic force microscopy. Carbon nanotubes were grown by chemical vapor deposition on the substrates with the prepared catalyst particles. By decreasing the catalyst particle size to below 10 nm, the growth of carbon nanotubes can be tuned from few-walled carbon nanotubes, with homogeneous diameter, to highly pure single-walled carbon nanotubes. Analysis of the Raman radial breathing modes, using three different Raman excitation wavelengths (488, 633, and 785 nm), showed a relatively broad diameter distribution (0.8-1.4 nm) of single-walled carbon nanotubes with different chiralities. However, by changing the composition of the catalyst particles while maintaining the growth parameters, the chiralities of single-walled carbon nanotubes were reduced to mainly four different types, (12, 1), (12, 0), (8, 5), and (7, 5), accounting for about 70% of all nanotubes.
|
|
| 4. |
- Bielig, H, et al.
(författare)
-
NOD-like receptor activation by outer-membrane vesicles (OMVs) from non-O1 non-O139 Vibrio cholerae is modulated by the quorum sensing regulator HapR
- 2011
-
Ingår i: Infection and Immunity. - : American Society for Microbiology. - 0019-9567 .- 1098-5522. ; 79:4, s. 1418-1427
-
Tidskriftsartikel (refereegranskat)abstract
- Vibrio cholerae is an inhabitant of aquatic systems and one of the causative agents of severe dehydrating diarrhea in humans. It has also emerged as an important cause of different kinds of inflammatory responses and in particular, V. cholerae strains of the non-O1 non-O139 serogroups (NOVC) have been associated with such infections in human. We analyzed the potential of outer membrane vesicles (OMVs) derived from the NOVC strain V:5/04 to induce inflammatory responses in human host cells. V:5/04 OMVs were taken up by human epithelial cells and induced inflammatory responses. siRNA-mediated gene knock-down revealed that the inflammatory potential of NOVC OMVs was partially mediated by the nucleotide-binding domain, leucine rich repeat containing family member NOD1. Physiochemical analysis of the content of these OMVs, in conjunction with NOD1 and NOD2 reporter assays in HEK293T cells, confirmed the presence of both NOD1 and NOD2 active peptidoglycan in the OMVs. Furthermore, we show that deletion of the quorum sensing regulator HapR which mimics an infective life style, specifically reduced the inflammatory potential of the V:5/04 OMVs and their ability to activate NOD1 and NOD2. In conclusion, our study shows that NOVC OMVs elicit immune responses mediated by NOD1 and NOD2 in mammalian host cells. Moreover, we provide evidence that the quorum sensing machinery plays an important regulatory role in this process by attenuating the inflammatory potential of OMVs in infective conditions. This work thus identified a new facet of how Vibrio affects host immune responses and defines a role for the quorum sensing machinery in this process.
|
|
| 5. |
- Bjarnsholt, T., et al.
(författare)
-
Biofilm formation – what we can learn from recent developments
- 2018
-
Ingår i: Journal of Internal Medicine. - : Wiley-Blackwell. - 0954-6820 .- 1365-2796. ; 284:4, s. 332-345
-
Tidskriftsartikel (refereegranskat)abstract
- Although biofilms have been observed early in the history of microbial research, their impact has only recently been fully recognized. Biofilm infections, which contribute to up to 80% of human microbial infections, are associated with common human disorders, such as diabetes mellitus and poor dental hygiene, but also with medical implants. The associated chronic infections such as wound infections, dental caries and periodontitis significantly enhance morbidity, affect quality of life and can aid development of follow-up diseases such as cancer. Biofilm infections remain challenging to treat and antibiotic monotherapy is often insufficient, although some rediscovered traditional compounds have shown surprising efficiency. Innovative anti-biofilm strategies include application of anti-biofilm small molecules, intrinsic or external stimulation of production of reactive molecules, utilization of materials with antimicrobial properties and dispersion of biofilms by digestion of the extracellular matrix, also in combination with physical biofilm breakdown. Although basic principles of biofilm formation have been deciphered, the molecular understanding of the formation and structural organization of various types of biofilms has just begun to emerge. Basic studies of biofilm physiology have also resulted in an unexpected discovery of cyclic dinucleotide second messengers that are involved in interkingdom crosstalk via specific mammalian receptors. These findings even open up new venues for exploring novel anti-biofilm strategies.
|
|
| 6. |
|
|
| 7. |
- Cabak, Andrea, et al.
(författare)
-
Activity of airway antimicrobial peptides against cystic fibrosis pathogens
- 2020
-
Ingår i: Pathogens and Disease. - : Oxford University Press. - 2049-632X. ; 78:7
-
Tidskriftsartikel (refereegranskat)abstract
- Antimicrobial peptides are important players of the innate host defence against invading microorganisms. The aim of this study was to evaluate the activity of airway antimicrobial peptides against the common cystic fibrosis (CF) pathogen Pseudomonas aeruginosa, and to compare it to the emerging multi-drug resistant CF pathogens Achromobacter xylosoxidans and Stenotrophomonas maltophilia. Clinical bacterial isolates from CF patients were used, and the antimicrobial activity of human beta-defensin 2 and 3, LL37 and lysozyme was evaluated using radial diffusion assay and viable counts. The cell surface zeta potential was analysed to estimate the net charge at the bacterial surface. Of the bacterial species included in the study, A. xylosoxidans was the most resistant to antimicrobial peptides, whereas P. aeruginosa was the most susceptible. The net charge of the bacterial surface was significantly more negative for P. aeruginosa compared to A. xylosoxidans, which may in part explain the differences in susceptibility.
|
|
| 8. |
- Cant, David J. H., et al.
(författare)
-
Cryo-XPS for surface characterization of nanomedicines
- 2023
-
Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 127:39, s. 8220-8227
-
Tidskriftsartikel (refereegranskat)abstract
- Nanoparticles used for medical applications commonly possess coatings or surface functionalities intended to provide specific behavior in vivo, for example, the use of PEG to provide stealth properties. Direct, quantitative measurement of the surface chemistry and composition of such systems in a hydrated environment has thus far not been demonstrated, yet such measurements are of great importance for the development of nanomedicine systems. Here we demonstrate the first use of cryo-XPS for the measurement of two PEG-functionalized nanomedicines: a polymeric drug delivery system and a lipid nanoparticle mRNA carrier. The observed differences between cryo-XPS and standard XPS measurements indicate the potential of cryo-XPS for providing quantitative measurements of such nanoparticle systems in hydrated conditions.
|
|
| 9. |
- Chung, Jade C. S., et al.
(författare)
-
Type III secretion system expression in oxygen-limited Pseudomonas aeruginosa cultures is stimulated by isocitrate lyase activity
- 2013
-
Ingår i: Open Biology. - : Royal Society of Chemistry. - 2046-2441. ; 3
-
Tidskriftsartikel (refereegranskat)abstract
- Pseudomonas aeruginosa is an opportunistic human pathogen and a common cause of chronic infections in individuals with cystic fibrosis (CF). Oxygen limitation was recently reported to regulate the expression of a major virulence determinant in P. aeruginosa, the type III secretion system (T3SS). Here, we show that expression of the T3SS in oxygen-limited growth conditions is strongly dependent on the glyoxylate shunt enzyme, isocitrate lyase (ICL; encoded by aceA), which was previously shown to be highly expressed in CF isolates. ICL-dependent regulation of the T3SS did not alter the expression level of the master transcriptional regulator, ExsA, but did affect expression of the T3 structural proteins, effectors and regulators (ExsC, ExsD and ExsE). An aceA mutant displayed enhanced biofilm formation during anaerobic growth, which suggested that AceA-dependent modulation of type III secretion might impinge upon the RetS/LadS signalling pathways. Indeed, our data suggest that RetS is able to mediate some of its effects through AceA, as expression of aceA in trans partially restored T3SS expression in a retS mutant. Our findings indicate that AceA is a key player in the metabolic regulation of T3SS expression during oxygen-limited growth of P. aeruginosa. To the best of our knowledge, this is the first demonstration that the T3SS can be regulated by factors that do not affect ExsA expression levels.
|
|
| 10. |
- Dardouri, Maïssa, et al.
(författare)
-
Assuring the Biofunctionalization of Silicone Covalently Bonded to Rhamnolipids : Antibiofilm Activity and Biocompatibility
- 2022
-
Ingår i: Pharmaceutics. - : MDPI. - 1999-4923 .- 1999-4923. ; 14:9
-
Tidskriftsartikel (refereegranskat)abstract
- Silicone-based medical devices composed of polydimethylsiloxane (PDMS) are widely used all over the human body (e.g., urinary stents and catheters, central venous catheters stents) with extreme clinical success. Nevertheless, their abiotic surfaces, being prone to microorganism colonization, are often involved in infection occurrence. Improving PDMS antimicrobial properties by surface functionalization with biosurfactants to prevent related infections has been the goal of different works, but studies that mimic the clinical use of these novel surfaces are missing. This work aims at the biofunctional assessment of PDMS functionalized with rhamnolipids (RLs), using translational tests that more closely mimic the clinical microenvironment. Rhamnolipids were covalently bonded to PDMS, and the obtained surfaces were characterized by contact angle modification assessment, ATR-FTIR analysis and atomic force microscopy imaging. Moreover, a parallel flow chamber was used to assess the Staphylococcus aureus antibiofilm activity of the obtained surfaces under dynamic conditions, and an in vitro characterization with human dermal fibroblast cells in both direct and indirect characterization assays, along with an in vivo subcutaneous implantation assay in the translational rabbit model, was performed. A 1.2 log reduction in S. aureus biofilm was observed after 24 h under flow dynamic conditions. Additionally, functionalized PDMS lessened cell adhesion upon direct contact, while supporting a cytocompatible profile, within an indirect assay. The adequacy of the biological response was further validated upon in vivo subcutaneous tissue implantation. An important step was taken towards biofunctional assessment of RLs-functionalized PDMS, reinforcing their suitability for medical device usage and infection prevention.
|
|
