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| 2. |
- Andersson, Edvin K. W., et al.
(författare)
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Initial SEI formation in LiBOB-, LiDFOB- and LiBF4-containing PEO electrolytes
- 2024
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 12:15, s. 9184-9199
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Tidskriftsartikel (refereegranskat)abstract
- A limiting factor for solid polymer electrolyte (SPE)-based Li-batteries is the functionality of the electrolyte decomposition layer that is spontaneously formed at the Li metal anode. A deeper understanding of this layer will facilitate its improvement. This study investigates three SPEs – polyethylene oxide:lithium tetrafluoroborate (PEO:LiBF4), polyethylene oxide:lithium bis(oxalate)borate (PEO:LiBOB), and polyethylene oxide:lithium difluoro(oxalato)borate (PEO:LiDFOB) – using a combination of electrochemical impedance spectroscopy (EIS), galvanostatic cycling, in situ Li deposition photoelectron spectroscopy (PES), and ab initio molecular dynamics (AIMD) simulations. Through this combination, the cell performance of PEO:LiDFOB can be connected to the initial SPE decomposition at the anode interface. It is found that PEO:LiDFOB had the highest capacity retention, which is correlated to having the least decomposition at the interface. This indicates that the lower SPE decomposition at the interface still creates a more effective decomposition layer, which is capable of preventing further electrolyte decomposition. Moreover, the PES results indicate formation of polyethylene in the SEI in cells based on PEO electrolytes. This is supported by AIMD that shows a polyethylene formation pathway through free-radical polymerization of ethylene.
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| 3. |
- Atefyekta, Saba, 1987, et al.
(författare)
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Antimicrobial Peptide-Functionalized Mesoporous Hydrogels
- 2021
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Ingår i: ACS Biomaterials Science & Engineering. - : American Chemical Society (ACS). - 2373-9878. ; 7:4, s. 1693-1702
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Tidskriftsartikel (refereegranskat)abstract
- Antimicrobial peptides (AMPs) are seen as a promising replacement to conventional antibiotics for the prevention of skin wound infections. However, due to the short half-life of AMPs in biological environments, such as blood, their use in clinical applications has been limited. The covalent immobilization of AMPs onto suitable substrates is an effective solution to create contact-killing surfaces with increased long-term stability. In this work, an antimicrobial peptide, RRPRPRPRPWWWW-NH2 (RRP9W4N), was covalently attached to amphiphilic and ordered mesoporous Pluronic F127 hydrogels made of cross-linked lyotropic liquid crystals through 1-ethyl-3-(3-(dimethylamino)propyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) chemistry. The AMP-hydrogels showed high antibacterial activity against Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, methicillin-resistant S. aureus (MRSA), and multidrug-resistant Escherichia coli for up to 24 h. Furthermore, the AMP-hydrogels did not present any toxicity to human fibroblasts. The AMPs retained their antimicrobial activity up to 48 h in human blood serum, which is a significant increase in stability compared to when used in dissolved state. A pilot in vivo rat model showed 10-100x less viable counts of S. aureus on AMP-hydrogels compared with control hydrogels during the first 3 days of infection. Studies performed on human whole blood showed that blood coagulated more readily in the presence of AMP-hydrogels as compared to hydrogels without AMPs, indicating potential hemostatic activity. Overall, the results suggest that the combination of amphiphilic hydrogels with covalently bonded AMPs has potential to be used as antibacterial wound dressing material to reduce infections and promote hemostatic activity as an alternative to antibiotics or other antimicrobial agents, whose use should be restricted.
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| 4. |
- Bertoli, Luca, et al.
(författare)
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Combination of solid polymer electrolytes and lithiophilic zinc for improved plating/stripping efficiency in anode-free lithium metal solid-state batteries
- 2023
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 464
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Tidskriftsartikel (refereegranskat)abstract
- Anode-free lithium metal batteries and solid-state batteries represent some of the most promising alternatives to the current Li-ion technology. The possibility to reach high energy density, due to the exploitation of Li-metal plating/stripping and the elimination of excess anode material, motivate the interest at both academic and in-dustrial levels. Despite these favourable properties, the use of Li-metal has always been extremely challenging and inefficient. This becomes particularly relevant in anode-free systems where no excess of lithium is introduced in the cell. The efficiency and quality of the deposition process is therefore of utmost importance. To optimize the Li-metal plating process, a combination of solid polymer electrolytes and a lithiophilic metal is applied herein, using in situ deposition of a zinc interlayer from a PEO-based SPE to modify the Cu current collector. Im-provements in specific capacity, coulombic efficiency and cyclability with the addition of zinc as lithiophilic metal is verified in full anode-free solid-state Li-batteries, while plating/stripping in half-cell configuration provides additional insights into the relevant mechanisms. The exploitation of the in situ deposited lithiophilic layer reveals an innovative and practical optimization strategy for the future of anode-free solid-state batteries.
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| 5. |
- Blomstrand, Edvin, 1993, et al.
(författare)
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Antibacterial and Hemolytic Activity of Antimicrobial Hydrogels Utilizing Immobilized Antimicrobial Peptides
- 2024
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Ingår i: INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES. - 1661-6596 .- 1422-0067. ; 25:8
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Tidskriftsartikel (refereegranskat)abstract
- Antimicrobial peptides (AMPs) are viewed as potential compounds for the treatment of bacterial infections. Nevertheless, the successful translation of AMPs into clinical applications has been impeded primarily due to their low stability in biological environments and potential toxicological concerns at higher concentrations. The covalent attachment of AMPs to a material's surface has been sought to improve their stability. However, it is still an open question what is required to best perform such an attachment and the role of the support. In this work, six different AMPs were covalently attached to a long-ranged ordered amphiphilic hydrogel, with their antibacterial efficacy evaluated and compared to their performance when free in solution. Among the tested AMPs were four different versions of synthetic end-tagged AMPs where the sequence was altered to change the cationic residue as well as to vary the degree of hydrophobicity. Two previously well-studied AMPs, Piscidin 1 and Omiganan, were also included as comparisons. The antibacterial efficacy against Staphylococcus aureus remained largely consistent between free AMPs and those attached to surfaces. However, the activity pattern against Pseudomonas aeruginosa on hydrogel surfaces displayed a marked contrast to that observed in the solution. Additionally, all the AMPs showed varying degrees of hemolytic activity when in solution. This activity was entirely diminished, and all the AMPs were non-hemolytic when attached to the hydrogels.
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| 6. |
- Blomstrand, Edvin, 1993, et al.
(författare)
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Clinical investigation of use of an antimicrobial peptide hydrogel wound dressing on intact skin
- 2023
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Ingår i: Journal of Wound Care. - 2052-2916 .- 0969-0700. ; 32:6, s. 368-375
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Tidskriftsartikel (refereegranskat)abstract
- A material with the ability to rapidly eradicate bacteria via a contact-killing mechanism has the benefit of a more localised treatment that is easy to implement when needed to prevent or treat a bacterial infection. Here, we present an antimicrobial material based on covalently attached antimicrobial peptides (AMPs) to a soft amphiphilic hydrogel. This results in a material that exhibits an antimicrobial effect based on contact-killing. In this study, the antimicrobial efficacy of the AMP-hydrogel was investigated by observing the changes in total bioburden on the intact skin of healthy human volunteers when the AMP-hydrogel dressing was placed on the forearm for three hours. The AMP-hydrogel significantly reduced the bioburden on the skin from a mean value of 1200CFU/cm2 for the untreated skin to 23CFU/cm2. Biocompatibility evaluations of the AMP-hydrogel showed no sign of cytotoxicity, acute systemic toxicity, irritation or sensitisation, demonstrating the safety of the AMP-hydrogel as a potential wound dressing. Leachability studies confirmed no release of AMPs and that the antimicrobial effect was localised to the surface of the hydrogels, demonstrating a pure contact-killing mode of action.
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| 7. |
- Blomstrand, Edvin, 1993, et al.
(författare)
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Cross-linked lyotropic liquid crystal particles functionalized with antimicrobial peptides
- 2022
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Ingår i: International Journal of Pharmaceutics. - : Elsevier BV. - 0378-5173 .- 1873-3476. ; 627
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Tidskriftsartikel (refereegranskat)abstract
- Antimicrobial peptides (AMPs) are promising alternatives to traditional antibiotics for addressing bacterial infections – including life-threatening antibiotic resistant infections. AMPs have a broad spectrum of antimicrobial activity and show a low probability to induce resistance. However, the poor serum stability of AMPs has limited their usage in clinical treatment. To enable improved serum stability while maintaining high antibacterial effect of AMPs, this study describes a material wherein AMPs are covalently bonded to micro-sized particles of cross-linked lyotropic liquid crystals, formed by the self-assembly of the block copolymer Pluronic F-127. The liquid crystal particles were shown to have antibacterial effect corresponding to a 4 log reduction against Staphylococcus aureus. The particles were structurally and chemically analyzed by small angle X-ray scattering, Fourier transform infra-red spectroscopy and Raman spectroscopy, confirming that the liquid crystal structure was maintained within the particles with the AMPs covalently bonded. The bonding to the particles gave the AMPs improved stability in serum, as they retained almost all of the antibacterial potency for 2 days compared to free AMPs, which lost all of its antibacterial potency within a day. Furthermore, insight regarding mode of action was obtained by cryogenic transmission electron microscopy, which showed the antimicrobial particles interacting with the surface of bacteria.
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| 8. |
- Börjesson, Anders, et al.
(författare)
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Molecular modelling of oxygen and water permeation in polyethylene
- 2013
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Ingår i: Polymer. - : Elsevier. - 0032-3861 .- 1873-2291. ; 54:12, s. 2988-
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Tidskriftsartikel (refereegranskat)abstract
- Monte Carlo and molecular dynamics simulations were performed to calculate solubility, S, and diffusion, D, coefficients of oxygen and water in polyethylene, and to obtain a molecular-level understanding of the diffusion mechanism. The permeation coefficient, P, was calculated from the product of S and D. The AMBER force field, which yields the correct polymer densities under the conditions studied, was used for the simulations, and it was observed that the results were not sensitive to the inclusion of atomic charges in the force field. The simulated S for oxygen and water are higher and lower than experimental data, respectively. The calculated diffusion coefficients are in good agreement with experimental data. Possible reasons for the discrepancy in the simulated and experimental solubilities, which results in discrepancies in the permeation coefficients, are discussed. The diffusion of both penetrants occurs mainly by large amplitude, infrequent jumps of the molecules through the polymer matrix.
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| 9. |
- Erdtman, Edvin, et al.
(författare)
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A molecular-level computational study of the diffusion and solubility of water and oxygen in carbonaceous polyethylene nanocomposites
- 2016
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Ingår i: Journal of Polymer Science Part B. - : Wiley. - 0887-6266 .- 1099-0488. ; 54:5, s. 589-602
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Tidskriftsartikel (refereegranskat)abstract
- Monte Carlo and molecular dynamics simulations were performed to investigate the effect on the solubility, diffusion, and permeability of water and oxygen when adding graphene or single-walled carbon nanotubes (SWCNTs) to polyethylene (PE). When compared with pure PE, addition of graphene lowered the solubility of water, whereas at lower temperatures, the oxygen solubility increased because of the oxygen–graphene interaction. Addition of SWCNTs lowered the solubility of both water and oxygen when compared with pure PE. A detailed analysis showed that an ordered structure of PE is induced near the additive surface, which leads to a decrease in the diffusion coefficient of both penetrants in this region. The addition of graphene does not change the permeation coefficient of oxygen (in the direction parallel to the filler) and, in fact, may even increase this coefficient when compared with pure PE. In contrast, the water permeability is decreased when graphene is added to PE. The addition of SWCNTs decreases the permeability of both penetrants. Graphene can consequently be added to selectively increase the solubility and permeation of oxygen over water, at least at lower temperatures. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 589–602
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