| 1. |
- Alarcon, Emilio I, et al.
(författare)
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The biocompatibility and antibacterial properties of collagen-stabilized, photochemically prepared silver nanoparticles
- 2012
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Ingår i: Biomaterials. - : Elsevier. - 0142-9612 .- 1878-5905. ; 33:19, s. 4947-4956
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Tidskriftsartikel (refereegranskat)abstract
- Spherical 3.5 nm diameter silver nanoparticles (AgNP) stabilized in type I collagen (AgNP@collagen) were prepared in minutes (5-15 min) at room temperature by a photochemical method initiated by UVA irradiation of a water-soluble non-toxic benzoin. This biocomposite was examined to evaluate its biocompatibility and its anti-bacterial properties and showed remarkable properties. Thus, while keratinocytes and fibroblasts were not affected by AgNP@collagen, it was bactericidal against Bacillus megaterium and E. coli but only bacteriostatic against S. epidermidis. In particular, the bactericidal properties displayed by AgNP@collagen were proven to be due to AgNP in AgNP@collagen, rather than to released silver ions, since equimolar concentrations of Ag are about four times less active than AgNP@collagen based on total Ag content. This new biocomposite was stable over a remarkable range of NaCl, phosphate, and 2-(N-morpholino)ethanesulfonic acid concentrations and for over one month at 4 degrees C. Circular dichroism studies show that the conformation of collagen in AgNP@collagen remains intact. Finally, we have compared the properties of AgNP@collagen with a similar biocomposite prepared using alpha-poly-L-Lysine and also with citrate stabilized AgNP; neither of these materials showed comparable biocompatibility, stability, or anti-bacterial activity.
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| 2. |
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| 3. |
- Bengtsson, Torbjörn, 1955-, et al.
(författare)
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Plantaricin NC8 αβ exerts potent antimicrobial activity against Staphylococcus spp. and enhances the effects of antibiotics
- 2020
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- The use of conventional antibiotics has substantial clinical efficacy, however these vital antimicrobial agents are becoming less effective due to the dramatic increase in antibiotic-resistant bacteria. Novel approaches to combat bacterial infections are urgently needed and bacteriocins represent a promising alternative. In this study, the activities of the two-peptide bacteriocin PLNC8 αβ were investigated against different Staphylococcus spp. The peptide sequences of PLNC8 α and β were modified, either through truncation or replacement of all L-amino acids with D-amino acids. Both L- and D-PLNC8 αβ caused rapid disruption of lipid membrane integrity and were effective against both susceptible and antibiotic resistant strains. The D-enantiomer was stable against proteolytic degradation by trypsin compared to the L-enantiomer. Of the truncated peptides, β1-22, β7-34 and β1-20 retained an inhibitory activity. The peptides diffused rapidly (2 min) through the bacterial cell wall and permeabilized the cell membrane, causing swelling with a disorganized peptidoglycan layer. Interestingly, sub-MIC concentrations of PLNC8 αβ substantially enhanced the effects of different antibiotics in an additive or synergistic manner. This study shows that PLNC8 αβ is active against Staphylococcus spp. and may be developed as adjuvant in combination therapy to potentiate the effects of antibiotics and reduce their overall use.
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| 4. |
- 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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| 5. |
- 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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| 6. |
- Eskilson, Olof, 1992-, et al.
(författare)
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Self-Assembly of Mechanoplasmonic Bacterial Cellulose-Metal Nanoparticle Composites
- 2020
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Ingår i: Advanced Functional Materials. - : Wiley-VCH Verlagsgesellschaft. - 1616-301X .- 1616-3028. ; 30:40
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Tidskriftsartikel (refereegranskat)abstract
- Nanocomposites of metal nanoparticles (NPs) and bacterial nanocellulose (BC) enable fabrication of soft and biocompatible materials for optical, catalytic, electronic, and biomedical applications. Current BC-NP nanocomposites are typically prepared by in situ synthesis of the NPs or electrostatic adsorption of surface functionalized NPs, which limits possibilities to control and tune NP size, shape, concentration, and surface chemistry and influences the properties and performance of the materials. Here a self-assembly strategy is described for fabrication of complex and well-defined BC-NP composites using colloidal gold and silver NPs of different sizes, shapes, and concentrations. The self-assembly process results in nanocomposites with distinct biophysical and optical properties. In addition to antibacterial materials and materials with excellent senor performance, materials with unique mechanoplasmonic properties are developed. The homogenous incorporation of plasmonic gold NPs in the BC enables extensive modulation of the optical properties by mechanical stimuli. Compression gives rise to near-field coupling between adsorbed NPs, resulting in tunable spectral variations and enhanced broadband absorption that amplify both nonlinear optical and thermoplasmonic effects and enables novel biosensing strategies.
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| 7. |
- Fursatz, Marian, et al.
(författare)
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Functionalization of bacterial cellulose wound dressings with the antimicrobial peptide ε-poly-L-Lysine
- 2018
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Ingår i: Biomedical Materials. - : Institute of Physics Publishing (IOPP). - 1748-6041 .- 1748-605X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Wound dressings based on bacterial cellulose (BC) can form a soft and conformable protective layer that can stimulate wound healing while preventing bacteria from entering the wound. Bacteria already present in the wound can, however, thrive in the moist environment created by the BC dressing which can aggravate the healing process. Possibilities to render the BC antimicrobial without affecting the beneficial structural and mechanical properties of the material would hence be highly attractive. Here we present methods for functionalization of BC with ε-Poly-L-Lysine (ε-PLL), a non-toxic biopolymer with broad-spectrum antimicrobial activity. Low molecular weight ε-PLL was cross-linked in pristine BC membranes and to carboxymethyl cellulose (CMC) functionalized BC using carbodiimide chemistry. The functionalization of BC with ε-PLL inhibited growth of S. epidermidis on the membranes but did not affect the cytocompatibility to cultured human fibroblasts as compared to native BC. The functionalization had no significant effects on the nanofibrous structure and mechanical properties of the BC. The possibility to functionalize BC with ε-PLL is a promising, green and versatile approach to improve the performance of BC in wound care and other biomedical applications.
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| 8. |
- Junker, Johan, 1980-, et al.
(författare)
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Adipogenic, Chondrogenic and Osteogenic Differentiation of ClonallyDerived Human Dermal Fibroblasts
- 2010
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Ingår i: Cells Tissues Organs. - Basel : Karger AG. - 1422-6405 .- 1422-6421. ; 191:2, s. 105-118
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Tidskriftsartikel (refereegranskat)abstract
- The apparent need of an autologous cell source for tissueengineering applications has led researchers to explore thepresence of cells with stem cell plasticity in several humantissues. Dermal fibroblasts (FBs) are easy to harvest, expandin vitro and store, rendering them plausible candidates forcell-based therapies. The aim of the present study was toobserve the effects of adipogenic, chondrogenic and osteogenicinduction media on the phenotype of human FBs.Human preadipocytes obtained from fat tissue have beenproposed as an adult stem cell source with suitable characteristics,and were used as control cells in regard to their differentiationpotential. Routine staining, immunohistochemicalanalysis and alkaline phosphatase assay were employed,in order to study the phenotypic shift. FBs were shown topossess multilineage potential, giving rise to fat-, cartilageandbone-like cells. To exclude contaminant progenitor cellsor cell fusion giving rise to tissue with adipocyte-, chondrocyte-and osteoblast-like cells, single-cell cloning was performed.Single-cell-cloned FBs (sccFBs) displayed a similardifferentiation potential as primary-culture FBs. The pres-ence of ‘stem-cell-specific’ surface antigens was analyzedusing flow cytometry. The results reveal that sccFBs haveseveral of the markers associated with cells exhibiting stemcell plasticity. The findings presented here are corroboratedby the findings of other groups, and suggest the use of humandermal FBs in cell-based therapies for the reconstructionof fat, cartilage and bone.
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| 9. |
- Lee, Chyan-Jang, et al.
(författare)
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Cathelicidin LL-37 and HSV-1 Corneal Infection : Peptide Versus Gene Therapy
- 2014
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Ingår i: Translational Vision Science & Technology. - : Association for Research in Vision and Ophthalmology. - 2164-2591. ; 3:3, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate the potential utility of collagen-based corneal implants with anti?Herpes Simplex Virus (HSV)-1 activity achieved through sustained release of LL-37, from incorporated nanoparticles, as compared with cell-based delivery from model human corneal epithelial cells (HCECs) transfected to produce endogenous LL-37. Methods: We tested the ability of collagen-phosphorylcholine implants to tolerate the adverse microenvironment of herpetic murine corneas. Then, we investigated the efficacy of LL-37 peptides delivered through nanoparticles incorporated within the corneal implants to block HSV-1 viral activity. In addition, LL-37 complementary DNA (cDNA) was transferred into HCECs to confer viral resistance, and their response to HSV-1 infection was examined. Results: Our implants remained in herpetic murine corneas 7 days longer than allografts. LL-37 released from the implants blocked HSV-1 infection of HCECs by interfering with viral binding. However, in pre-infected HCECs, LL-37 delayed but could not prevent viral spreading nor clear viruses from the infected cells. HCECs transfected with the LL-37 expressed and secreted the peptide. Secreted LL-37 inhibited viral binding in vitro but was insufficient to protect cells completely from HSV-1 infection. Nevertheless, secreted LL-37 reduced both the incidence of plaque formation and plaque size. Conclusion: LL-37 released from composite nanoparticle-hydrogel corneal implants and HCEC-produced peptide, both showed anti?HSV-1 activity by blocking binding. However, while both slowed down virus spread, neither was able on its own to completely inhibit the viruses. Translational Relevance: LL-37 releasing hydrogels may have potential utility as corneal substitutes for grafting in HSV-1 infected corneas, possibly in combination with LL-37 producing therapeutic cells.
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| 10. |
- Mak, Wing Cheung, et al.
(författare)
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Controlled Delivery of Human Cells by Temperature Responsive Microcapsules
- 2015
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Ingår i: Journal of Functional Biomaterials. - : MDPI. - 2079-4983. ; 6:2, s. 439-453
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Tidskriftsartikel (refereegranskat)abstract
- Cell therapy is one of the most promising areas within regenerative medicine. However, its full potential is limited by the rapid loss of introduced therapeutic cells before their full effects can be exploited, due in part to anoikis, and in part to the adverse environments often found within the pathologic tissues that the cells have been grafted into. Encapsulation of individual cells has been proposed as a means of increasing cell viability. In this study, we developed a facile, high throughput method for creating temperature responsive microcapsules comprising agarose, gelatin and fibrinogen for delivery and subsequent controlled release of cells. We verified the hypothesis that composite capsules combining agarose and gelatin, which possess different phase transition temperatures from solid to liquid, facilitated the destabilization of the capsules for cell release. Cell encapsulation and controlled release was demonstrated using human fibroblasts as model cells, as well as a therapeutically relevant cell line—human umbilical vein endothelial cells (HUVECs). While such temperature responsive cell microcapsules promise effective, controlled release of potential therapeutic cells at physiological temperatures, further work will be needed to augment the composition of the microcapsules and optimize the numbers of cells per capsule prior to clinical evaluation.
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| 11. |
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| 12. |
- Råberg, Tora, et al.
(författare)
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Potentiella kolsänkor i Malmö stad
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Miljöförvaltningen inom Malmö stad gav RISE uppdraget att identifiera möjligheter att öka kolsänkorna inom kommungränsen. Syftet med den här rapporten är att sammanställa ett brett underlag för klimatarbete med åtgärder som möjliggör en ökning av de lokala kolsänkorna i Malmö stads geografiska område. Genom att uppskatta olika åtgärders potential för kolinlagring, teknisk mognadsgrad och kostnadseffektivitet från ett klimatperspektiv, samt visa på vilka skalor det går att jobba med dessa åtgärder inom kommunen, avses rapporteringen ge en översikt över vilka satsningar som kan göras för att kolsänkorna ska kunna bidra till Malmö stads miljö- och klimatmål. Forskargruppen från RISE har analyserat 18 olika kategorier som har potential att öka den lokala kolinlagringen inom: • de urbana grönområdena, • den urbana infrastrukturen, bebyggd mark och tillhörande mark • rural markanvändning och • övriga möjligheter. I beräkningarna ingår inte klimatpåverkan från insatser som krävs för att genomföra åtgärderna, till exempel avverkning, uppdrivning och plantering av skogsplantor, transport av timmer och förädling av virke. I rapporten tas inte hänsyn till om en ökad användning av mark i en kategori, minskar markanvändning inom en annan kategori.
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| 13. |
- Sivler, Tobias, et al.
(författare)
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Treatment of Nonhealing Ulcers with an Allograft/Xenograft Substitute: A Case Series
- 2018
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Ingår i: Advances in Skin & Wound Care. - : LIPPINCOTT WILLIAMS & WILKINS. - 1527-7941 .- 1538-8654. ; 31:7, s. 306-309
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Wound dressings that use biosynthetic cellulose may be a good alternative to dressings currently used to treat chronic and acute ulcers because their nanostructure is similar to collagen. The objective of this study was to evaluate a wound dressing created with a new material that is composed of a fibrillary network of biosynthetic cellulose. METHODS: A case series of 8 patients in primary healthcare centers in ostergotland county council, Sweden, with chronic and acute lower limb wounds were treated with a wound dressing based on eiratex (S2Medical AB, Linkoping, Sweden). The dressing was applied to traumatic (n = 5) and venous ulcers (n = 3). All ulcers were considered healed at the end of the treatment. MAIN OUTCOME MEASURE: The wounds were examined at regular intervals by a physician to determine healing time, number of dressing changes, and number of visits. MAIN RESULTS: Mean healing time was 43 6 days after the first application of the dressing. The mean number of visits was 5.7 +/- 0.6, and the mean number of dressings used per patient was 1.7 +/- 0.2. CONCLUSIONS: These results demonstrate the efficacy of a wound dressing made of eiratex to heal chronic and acute ulcers. The data show that the number of dressings used and dressing changes needed to heal the ulcers are lower than what have been reported in the literature for other dressing materials.
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| 14. |
- Skog, Mårten, 1982-, et al.
(författare)
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The Effect of Enzymatic Digestion on Cultured Epithelial Autografts
- 2019
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Ingår i: Cell Transplantation. - : Sage Publications. - 0963-6897 .- 1555-3892. ; 28:5, s. 638-644
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Tidskriftsartikel (refereegranskat)abstract
- Severe burns are often treated by means of autologous skin grafts, preferably following early excision of the burnt tissue. In the case of, for example, a large surface trauma, autologous skin cells can be expanded in vitro prior to transplantation to facilitate the treatment when insufficient uninjured skin is a limitation. In this study we have analyzed the impact of the enzyme (trypsin or accutase) used for cell dissociation and the incubation time on cell viability and expansion potential, as well as expression of cell surface markers indicative of stemness. Skin was collected from five individuals undergoing abdominal reduction surgery and the epidermal compartment was digested in either trypsin or accutase. Trypsin generally generated more cells than accutase and with higher viability; however, after 7 days of subsequent culture, accutase-digested samples tended to have a higher cell count than trypsin, although the differences were not significant. No significant difference was found between the enzymes in median fluorescence intensity of the analyzed stem cell markers; however, accutase digestion generated significantly higher levels of CD117- and CD49f-positive cells, but only in the 5 h digestion group. In conclusion, digestion time appeared to affect the isolated cells more than the choice of enzyme.
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| 15. |
- Strindhall, Jan, et al.
(författare)
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The inverted CD4/CD8 ratio and associated parameters in 66-year-old individuals : the Swedish HEXA immune study
- 2013
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Ingår i: Age (Omaha). - : Springer Netherlands. - 0161-9152 .- 1574-4647. ; 35:3, s. 985-991
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Tidskriftsartikel (refereegranskat)abstract
- The Swedish OCTO and NONA immune longitudinal studies were able to identify and confirm an immune risk profile (IRP) predictive of an increased 2-year mortality in very old individuals, 86–94 years of age. The IRP, was associated with persistent cytomegalovirus infection and characterized by inverted CD4/CD8 ratio and related to expansion of terminally differentiated effector memory T cells (TEMRA phenotype). In the present HEXA immune longitudinal study, we have examined a younger group of elderly individuals (n = 424, 66 years of age) in a population-based sample in the community of Jönköping, Sweden, to examine the relevance of findings previously demonstrated in the very old. Immunological monitoring that was conducted included T cell subsets and CMV-IgG and CMV-IgM serology. The result showed a prevalence of 15 % of individuals with an inverted CD4/CD8 ratio, which was associated with seropositivity to cytomegalovirus and increases in the level of TEMRA cells. The proportion of individuals with an inverted CD4/CD8 ratio was significantly higher in men whereas the numbers of CD3+CD4+ cells were significantly higher in women. In conclusion, these findings are very similar to those previously found by us in the Swedish longitudinal studies, suggesting that an immune profile previously identified in the very old also exists in the present sample of hexagenerians. Therefore, it will be important to examine clinical parameters, including morbidity and mortality, to assess whether the immune profile also is a risk profile associated with higher mortality in this sample of hexagenerians.
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