| 1. |
- Yaghmaeian Salmani, Behzad, 1978-, et al.
(author)
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Evolutionarily conserved anterior expansion of the central nervous system promoted by a common PcG-Hox program
- 2018
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In: Development. - Cambridge, United Kingdom : The Company of Biologists Ltd.. - 0950-1991 .- 1477-9129. ; 145:7
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Journal article (peer-reviewed)abstract
- A conserved feature of the central nervous system (CNS) is the prominent expansion of anterior regions (brain) compared with posterior (nerve cord). The cellular and regulatory processes driving anterior CNS expansion are not well understood in any bilaterian species. Here, we address this expansion in Drosophila and mouse. We find that, compared with the nerve cord, the brain displays extended progenitor proliferation, more elaborate daughter cell proliferation and more rapid cell cycle speed in both Drosophila and mouse. These features contribute to anterior CNS expansion in both species. With respect to genetic control, enhanced brain proliferation is severely reduced by ectopic Hox gene expression, by either Hox misexpression or by loss of Polycomb group (PcG) function. Strikingly, in PcG mutants, early CNS proliferation appears to be unaffected, whereas subsequent brain proliferation is severely reduced. Hence, a conserved PcG-Hox program promotes the anterior expansion of the CNS. The profound differences in proliferation and in the underlying genetic mechanisms between brain and nerve cord lend support to the emerging concept of separate evolutionary origins of these two CNS regions.
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| 2. |
- Baş, Yağmur, et al.
(author)
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Preparation and Characterization of Softwood and Hardwood Nanofibril Hydrogels: Toward Wound Dressing Applications
- 2023
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In: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 24:12, s. 5605-5619
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Journal article (peer-reviewed)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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| 3. |
- Berglund, Linn, et al.
(author)
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Self-Assembly of Nanocellulose Hydrogels Mimicking Bacterial Cellulose for Wound Dressing Applications
- 2023
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In: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 24:5, s. 2264-2277
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Journal article (peer-reviewed)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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| 4. |
- Berglund, Linn, et al.
(author)
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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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In: ACS Applied Bio Materials. - : American Chemical Society (ACS). - 2576-6422. ; 3:9, s. 6510-6520
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Journal article (peer-reviewed)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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| 5. |
- Eskilson, Olof, 1992-, et al.
(author)
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Nanocellulose composite wound dressings for real-time pH wound monitoring
- 2023
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In: Materials Today Bio. - : Elsevier. - 2590-0064. ; 19
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Journal article (peer-reviewed)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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| 6. |
- (Svensson) Nyman, Erika, 1976-, et al.
(author)
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Effects of amniotic fluid on human keratinocyte gene expression : Implications for wound healing
- 2022
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In: Experimental dermatology. - Chichester, United Kingdom : Wiley-Blackwell. - 0906-6705 .- 1600-0625. ; 31:5, s. 764-774
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Journal article (peer-reviewed)abstract
- Cutaneous wounds can lead to huge suffering for patients. Early fetal wounds have the capacity to regenerate without scar formation. Amniotic fluid (AF), containing hyaluronic acid (HA), may contribute to this regenerative environment. We aimed to analyse changes in gene expression when human keratinocytes are exposed to AF or HA. Human keratinocytes were cultured to subconfluence, starved for 12 h and then randomised to be maintained in (1) Dulbeccos modified Eagles medium (DMEM), (2) DMEM with 50% AF, or (3) DMEM with 50% fetal calf serum (FCS). Transcriptional changes were analysed using microarray and enriched with WebGestalt and Enrichr. Additionally, eight diagnostic genes were analysed using semiquantitative real-time PCR to investigate epidermal differentiation and cellular stress after HA exposure as an alternative for AF exposure. The AF and FCS treatments resulted in enrichment of genes relating to varied aspects of epidermal and keratinocyte biology. In particular, p63-, AP1- and NFE2L2- (Nrf2) associated genes were found significantly regulated in both treatments. More genes regulated by FCS treatment were associated with inflammatory signalling, whilst AF treatment was dominantly associated with molecular establishment of epidermis and lipid metabolic activity. HA exposure mostly resulted in gene regulation that was congruent with the AF microarray group, with increased expression of ITGA6 and LOR. We conclude that AF exposure enhances keratinocyte differentiation in vitro, which suggests that AF constituents can be beneficial for wound-healing applications.
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