| 1. |
- Gustafson, Carl-Johan, et al.
(författare)
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Employing human keratinocytes cultured on macroporous gelatin spheres to treat full thickness-wounds : an in vivo study on athymic rats.
- 2007
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Ingår i: Burns. - : Elsevier BV. - 0305-4179 .- 1879-1409. ; 33:6, s. 726-35
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Tidskriftsartikel (refereegranskat)abstract
- Providing cutaneous wounds with sufficient epidermis to prevent infections and fluid loss is one of the most challenging tasks associated with surgical treatment of burns. Recently, application of cultured keratinocytes in this context has allowed this challenge to be met without several of the limitations connected with the use of split-thickness skin grafts. The continuous development of this novel approach has now revealed that transplantation of cultured autologous keratinocytes as single-cell suspensions exhibits several advantages over the use of cultured epidermal grafts. However, a number of methodological problems remain to be solved, primarily with regards to the complexity of culturing these cells; loss of viability and other negative effects during their preparation and transportation; the relatively long period of time required following transplantation to obtain a sufficiently protective epidermis. In the present investigation we attempted to eliminate these limitations by culturing the keratinocytes on macroporous gelatin spheres. Accordingly, the efficacies of normal human keratinocytes in single-cell suspension or growing on macroporous gelatin spheres, as well as of split-thickness skin grafts in healing wounds on athymic rats were compared. Human keratinocytes were found to adhere and proliferate efficiently both on the surface and within the pores of such spheres. Transplantation of such cells adherent to the spheres resulted in significantly more rapid formation of a stratified epidermis than did transplantation of single-cell suspensions or spheres alone. Twenty-three days after transplantation, the epidermis formed from the cells bound to the spheres was not as thick as the epidermis on wounds covered with split-thickness skin grafts, but significantly thicker than on wounds to which single-cell suspensions, spheres alone or no transplant at all was applied. Furthermore, fluorescence in situ hybridisation revealed that the transplanted keratinocytes, both those adherent to gelatin spheres and those in single-cell suspension, were components of the newly formed epidermis. These findings indicate that application of biodegradable macroporous spheres may prove to be of considerable value in designing cell-based therapies for the treatment of acute and persistent wounds.
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| 2. |
- Seland, Havard, et al.
(författare)
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Transplantation of acellular dermis and keratinocytes cultured on porous biodegradable microcarriers into full-thickness skin injuries on athymic rats
- 2011
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Ingår i: BURNS. - : Elsevier Science B.V., Amsterdam.. - 0305-4179. ; 37:1, s. 99-108
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Tidskriftsartikel (refereegranskat)abstract
- In search of an optimal transplantation regime for sufficient dermal and epidermal regeneration after a full-thickness skin injury, wounds on athymic rats were grafted with split-thickness skin grafts or acellular human dermis followed by transplantation with human keratinocytes either in single-cell suspension or cultured on porous biodegradable micro-carriers. After 2 weeks, all wounds grafted with acellular human dermis showed a well organised and vascularised dermal component and reepithelialisation on the grafted dermal matrix was complete 21 days after transplantation with human keratinocytes. Wounds grafted with human keratinocytes seeded on biodegradable microcarriers or split-thickness skin grafts displayed over time (i.e. 16-21 days post-transplantation) a significantly thicker epithelial cell layer in comparison to wounds grafted with keratinocytes in single-cell suspensions or microcarriers not seeded with cells. Furthermore, measurements of dermal thickness in the closed wounds 21 days after grafting showed a significantly thicker and well organised neodermal component in wounds transplanted with keratinocytes seeded on microcarriers or split-thickness skin grafts compared to all other wounds. Positive immunostaining towards von Willebrand factor revealed the plausible proangiogenic effects of transplantation with keratinocytes seeded on microcarriers. Analysis of representative tissue sections after fluorescence in situ hybridisation visualised that grafted human keratinocytes were present in the epidermal layers covering the wounds 16 and 21 days after transplantation, strongly indicating preservation of cell viability. These results shows that the use of biodegradable microcarriers in the culture of autologous keratinocytes for treatment of full-thickness wounds not only facilitate the cultivation, transportation and transplantation processes but also enhances the dermal regeneration induced by a dermal scaffold which results in a clinical result that is significantly superior to the one obtained when keratinocytes are transplanted in a single-cell suspension.
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| 3. |
- Abgrall, N., et al.
(författare)
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The large enriched germanium experiment for neutrinoless double beta decay (LEGEND)
- 2017
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Ingår i: AIP Conference Proceedings. - : Author(s). - 1551-7616 .- 0094-243X. ; 1894
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Konferensbidrag (refereegranskat)abstract
- The observation of neutrinoless double-beta decay (0νββ) would show that lepton number is violated, reveal that neu-trinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of ∼0.1 count /(FWHM·t·yr) in the region of the signal. The current generation 76Ge experiments GERDA and the Majorana Demonstrator, utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0νββ signal region of all 0νββ experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale 76Ge experiment. The collaboration aims to develop a phased 0νββ experimental program with discovery potential at a half-life approaching or at 1028 years, using existing resources as appropriate to expedite physics results.
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| 4. |
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| 5. |
- Baş, Yağmur, et al.
(författare)
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Preparation and Characterization of Softwood and Hardwood Nanofibril Hydrogels: Toward Wound Dressing Applications
- 2023
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 24:12, s. 5605-5619
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogels of cellulose nanofibrils (CNFs) are promising wound dressing candidates due to their biocompatibility, high water absorption, and transparency. Herein, two different commercially available wood species, softwood and hardwood, were subjected to TEMPO-mediated oxidation to proceed with delignification and oxidation in a one-pot process, and thereafter, nanofibrils were isolated using a high-pressure microfluidizer. Furthermore, transparent nanofibril hydrogel networks were prepared by vacuum filtration. Nanofibril properties and network performance correlated with oxidation were investigated and compared with commercially available TEMPO-oxidized pulp nanofibrils and their networks. Softwood nanofibril hydrogel networks exhibited the best mechanical properties, and in vitro toxicological risk assessment showed no detrimental effect for any of the studied hydrogels on human fibroblast or keratinocyte cells. This study demonstrates a straightforward processing route for direct oxidation of different wood species to obtain nanofibril hydrogels for potential use as wound dressings, with softwood having the most potential.
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| 6. |
- Berglund, Linn, et al.
(författare)
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Self-Assembly of Nanocellulose Hydrogels Mimicking Bacterial Cellulose for Wound Dressing Applications
- 2023
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 24:5, s. 2264-2277
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Tidskriftsartikel (refereegranskat)abstract
- The self-assembly of nanocellulose in the form of cellulose nanofibers (CNFs) can be accomplished via hydrogen-bonding assistance into completely bio-based hydrogels. This study aimed to use the intrinsic properties of CNFs, such as their ability to form strong networks and high absorption capacity and exploit them in the sustainable development of effective wound dressing materials. First, TEMPO-oxidized CNFs were separated directly from wood (W-CNFs) and compared with CNFs separated from wood pulp (P-CNFs). Second, two approaches were evaluated for hydrogel self-assembly from W-CNFs, where water was removed from the suspensions via evaporation through suspension casting (SC) or vacuum-assisted filtration (VF). Third, the W-CNF-VF hydrogel was compared to commercial bacterial cellulose (BC). The study demonstrates that the self-assembly via VF of nanocellulose hydrogels from wood was the most promising material as wound dressing and displayed comparable properties to that of BC and strength to that of soft tissue.
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| 7. |
- Berglund, Linn, et al.
(författare)
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Utilizing the Natural Composition of Brown Seaweed for the Preparation of Hybrid Ink for 3D Printing of Hydrogels
- 2020
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Ingår i: ACS Applied Bio Materials. - : American Chemical Society (ACS). - 2576-6422. ; 3:9, s. 6510-6520
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Tidskriftsartikel (refereegranskat)abstract
- This study aims to utilize the natural composition of brown seaweed by deriving alginate and cellulose concurrently from the stipe (stem-like) and blade (leaf-like) structures of the seaweed; further, this is followed by fibrillation for the direct and resource-efficient preparation of alginate/cellulose nanofiber (CNF) hybrid inks for three-dimensional (3D) printing of hydrogels. The efficiency of the fibrillation process was evaluated, and the obtained gels were further studied with regard to their rheological behavior. As a proof of concept, the inks were 3D printed into discs, followed by cross-linking with CaCl2 to form biomimetic hydrogels. It was shown that the nanofibrillation process from both seaweed structures is very energy-efficient, with an energy demand lower than 1.5 kW h/kg, and with CNF dimensions below 15 nm. The inks displayed excellent shear-thinning behavior and cytocompatibility and were successfully printed into 3D discs that, after cross-linking, exhibited an interconnected network structure with favorable mechanical properties, and a cell viability of 71%. The designed 3D biomimetic hydrogels offers an environmentally benign, cost-efficient, and biocompatible material platform with a favorable structure for the development of biomedical devices, such as 3D bio printing of soft tissues.
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| 8. |
- Carvalheiro, Luisa Gigante, et al.
(författare)
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The potential for indirect effects between co-flowering plants via shared pollinators depends on resource abundance, accessibility and relatedness
- 2014
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 17:11, s. 1389-1399
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Tidskriftsartikel (refereegranskat)abstract
- Co-flowering plant species commonly share flower visitors, and thus have the potential to influence each other's pollination. In this study we analysed 750 quantitative plant-pollinator networks from 28 studies representing diverse biomes worldwide. We show that the potential for one plant species to influence another indirectly via shared pollinators was greater for plants whose resources were more abundant (higher floral unit number and nectar sugar content) and more accessible. The potential indirect influence was also stronger between phylogenetically closer plant species and was independent of plant geographic origin (native vs. non-native). The positive effect of nectar sugar content and phylogenetic proximity was much more accentuated for bees than for other groups. Consequently, the impact of these factors depends on the pollination mode of plants, e.g. bee or fly pollinated. Our findings may help predict which plant species have the greatest importance in the functioning of plant-pollination networks.
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| 9. |
- Eskilson, Olof, 1992-, et al.
(författare)
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Nanocellulose composite wound dressings for real-time pH wound monitoring
- 2023
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Ingår i: Materials Today Bio. - : Elsevier. - 2590-0064. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- The skin is the largest organ of the human body. Wounds disrupt the functions of the skin and can have catastrophic consequences for an individual resulting in significant morbidity and mortality. Wound infections are common and can substantially delay healing and can result in non-healing wounds and sepsis. Early diagnosis and treatment of infection reduce risk of complications and support wound healing. Methods for monitoring of wound pH can facilitate early detection of infection. Here we show a novel strategy for integrating pH sensing capabilities in state-of-the-art hydrogel-based wound dressings fabricated from bacterial nanocellulose (BC). A high surface area material was developed by self-assembly of mesoporous silica nanoparticles (MSNs) in BC. By encapsulating a pH-responsive dye in the MSNs, wound dressings for continuous pH sensing with spatiotemporal resolution were developed. The pH responsive BC-based nanocomposites demonstrated excellent wound dressing properties, with respect to conformability, mechanical properties, and water vapor transmission rate. In addition to facilitating rapid colorimetric assessment of wound pH, this strategy for generating functional BC-MSN nanocomposites can be further be adapted for encapsulation and release of bioactive compounds for treatment of hard-to-heal wounds, enabling development of novel wound care materials.
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| 10. |
- Huss, Fredrik R.M., et al.
(författare)
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Macroporous gelatine spheres as culture substrate, transplantation vehicle, and biodegradable scaffold for guided regeneration of soft tissues. : In vivo study in nude mice
- 2007
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Ingår i: Journal of Plastic, Reconstructive, and Aesthetic Surgery. - : Elsevier BV. - 1748-6815 .- 1878-0539. ; 60:5, s. 543-555
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Tidskriftsartikel (refereegranskat)abstract
- In the course of development of a new type of filler for the correction of small defects in soft tissues we studied macroporous gelatine spheres as culture substrate, transplantation vehicle, and biodegradable scaffold for guided regeneration of soft tissues in vivo. We injected intradermally in nude mice gelatine spheres that had either been preseeded with human fibroblasts or preadipocytes, or left unseeded. We compared the extent of regenerated tissue with that found after injections of saline or single-cell suspensions of human fibroblasts or preadipocytes. Routine histological examinations and immunohistochemical staining for von Willebrand factor (indicating neoangiogenesis) were made after 7, 21, and 56 days. Injected saline or single-cell suspensions had no effect. However, a quick and thorough tissue regeneration with developing neoangiogenesis was elicited by the gelatine spheres and the effect of spheres preseeded with preadipocytes surpassed the effect of spheres preseeded with fibroblasts, which in turn surpassed the effect of unseeded gelatine spheres. We suggest that minor soft tissue defects such as wrinkles or creases can be corrected by injection of naked macroporous gelatine spheres, whereas larger defects are best corrected by injection of macroporous gelatine spheres preseeded with fibroblasts, or preadipocytes, or both.
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