| 1. |
- Aimonen, Kukka, et al.
(författare)
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Role of Surface Chemistry in the In Vitro Lung Response to Nanofibrillated Cellulose
- 2021
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Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- Wood-derived nanofibrillated cellulose (NFC) has emerged as a sustainable material with a wide range of applications and increasing presence in the market. Surface charges are introduced during the preparation of NFC to facilitate the defibrillation process, which may also alter the toxicological properties of NFC. In the present study, we examined the in vitro toxicity of NFCs with five surface chemistries: nonfunctionalized, carboxymethylated, phosphorylated, sulfoethylated, and hydroxypropyltrimethylammonium-substituted. The NFC samples were characterized for surface functional group density, surface charge, and fiber morphology. Fibril aggregates predominated in the nonfunctionalized NFC, while individual nanofibrils were observed in the functionalized NFCs. Differences in surface group density among the functionalized NFCs were reflected in the fiber thickness of these samples. In human bronchial epithelial (BEAS-2B) cells, all NFCs showed low cytotoxicity (CellTiter-GloVR luminescent cell viability assay) which never exceeded 10% at any exposure time. None of the NFCs induced genotoxic effects, as evaluated by the alkaline comet assay and the cytokinesis-block micronucleus assay. The nonfunctionalized and carboxymethylated NFCs were able to increase intracellular reactive oxygen species (ROS) formation (chloromethyl derivative of 2 ',7 '-dichlorodihydrofluorescein diacetate assay). However, ROS induction did not result in increased DNA or chromosome damage.
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| 2. |
- Basu, Alex, et al.
(författare)
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Hemocompatibility of Ca2+-Crosslinked Nanocellulose Hydrogels : Toward Efficient Management of Hemostasis
- 2017
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Ingår i: Macromolecular Bioscience. - : Wiley. - 1616-5187 .- 1616-5195. ; 17:11
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Tidskriftsartikel (refereegranskat)abstract
- The present work investigates Ca2+-crosslinked nanofibrillated cellulose hydrogels as potential hemostatic wound dressings by studying core interactions between the materials and a central component of wounds and wound healing—the blood. Hydrogels of wood-derived anionic nanofibrillated cellulose (NFC) and NFC hydrogels that incorporate kaolin or collagen are studied in an in vitro whole blood model and with platelet-free plasma assays. The evaluation of thrombin and factor XIIa formation, platelet reduction, and the release of activated complement system proteins, shows that the NFC hydrogel efficiently triggered blood coagulation, with a rapid onset of clot formation, while displaying basal complement system activation. By using the NFC hydrogel as a carrier of kaolin, the onset of hemostasis is further boosted, while the NFC hydrogel containing collagen exhibits blood activating properties comparable to the anionic NFC hydrogel. The herein studied NFC hydrogels demonstrate great potential for being part of advanced wound healing dressings that can be tuned to target certain wounds (e.g., strongly hemorrhaging ones) or specific phases of the wound healing process for optimal wound management.
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| 3. |
- Basu, Alex, et al.
(författare)
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In Vitro and in Vivo Evaluation of the Wound Healing Properties of Nanofibrillated Cellulose Hydrogels
- 2018
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Ingår i: ACS Applied Bio Materials. - : American Chemical Society (ACS). - 2576-6422. ; 1:6, s. 1853-1863
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Tidskriftsartikel (refereegranskat)abstract
- Current trends in wound care research move toward the development of wound healing dressings designed to treat different types of wounds (e.g., burns and chronic wounds) and toward tailoring treatments for different stages of the wound healing process. In this context, the development of advanced nanotherapeutic materials is highlighted as a promising strategy to efficiently control specific phases of the wound healing process. Here, Ca2+-cross-linked wood-derived nanofibrillated cellulose (NFC) hydrogels are evaluated as wound healing dressings. In vitro biocompatibility assays were performed to study the interaction of the NFC hydrogels with cellular processes that are tightly related to wound healing. Moreover, an in vivo dermo-epidermic full thickness wound healing model in rat was used to uncover the wound healing ability of the Ca2+-cross-linked NFC hydrogels. The in vitro experiments showed that the NFC hydrogels were able to support fibroblast and keratinocyte proliferation. A potential effect of the hydrogels on triggering keratinocyte differentiation was furthermore proposed. In vivo, the NFC hydrogels stimulated healing without causing any adverse local tissue effects, potentially owing to their moisture-donating properties and the herein discussed aiding effect of the Ca2+-cross-linker on epidermal generation. Thus, this work extensively demonstrates the wound healing ability of NFC hydrogels and presents an important milestone in the research on NFC toward advanced wound healing applications.
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| 4. |
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| 5. |
- Basu, Alex, et al.
(författare)
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Ion-crosslinked wood-derived nanocellulose hydrogels with tunable antibacterial properties : Candidate materials for advanced wound care applications
- 2018
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 181, s. 345-350
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Tidskriftsartikel (refereegranskat)abstract
- Development of advanced dressings with antimicrobial properties for the treatment of infected wounds is an important approach in the fight against evolution of antibiotic resistant bacterial strains. Herein, the effects of ion-crosslinked nanocellulose hydrogels on bacteria commonly found in infected wounds were investigated in vitro. By using divalent calcium or copper ions as crosslinking agents, different antibacterial properties against the bacterial strains Staphylococcus epidermidis and Pseudomonas aeruginosa were obtained. Calcium crosslinked hydrogels were found to retard S. epidermidis growth (up to 266% increase in lag time, 36% increase in doubling time) and inhibited P. aeruginosa biofilm formation, while copper crosslinked hydrogels prevented S. epidermidis growth and were bacteriostatic towards P. aeruginosa (49% increase in lag time, 78% increase in doubling time). The wound dressing candidates furthermore displayed barrier properties towards both S. epidermidis and P. aeruginosa, hence making them interesting for further development of advanced wound dressings with tunable antibacterial properties.
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| 6. |
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| 7. |
- Basu, Alex, et al.
(författare)
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On the use of ion-crosslinked nanocellulose hydrogels for wound healing solutions : Physicochemical properties and application-oriented biocompatibility studies
- 2017
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 174, s. 299-308
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Tidskriftsartikel (refereegranskat)abstract
- Calcium ion-crosslinked nanofibrillated cellulose (NFC) hydrogels were investigated as potential materials for wound healing dressings. The physicochemical properties of the hydrogels were examined by rheology and water retention tests. Skin cells and monocytes were selected for application-oriented bio-compatibility studies. The NFC hydrogels presented entangled fibrous networks and solid-like behavior. Water retention tests showed the material's potential to maintain a suitable moist environment for different type of wounds. The hydrogels did not affect dermal fibroblasts monolayer cultures upon directcontact, as cell monolayers remained intact after application, incubation and removal of the materials. Inflammatory response studies with blood-derived mononuclear cells revealed the inert nature of the hydrogels in terms of cytokine secretion and reactive oxygen species production. Results highlight the great potential of ion-crosslinked NFC hydrogels for the development of advanced wound dressings, where further functionalization of the material could lead to improved properties towards the healing of specific wound types.
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| 8. |
- Basu, Alex, et al.
(författare)
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Towards Tunable Protein-Carrier Wound Dressings Based on Nanocellulose Hydrogels Crosslinked with Calcium Ions
- 2018
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Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 8:7
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Tidskriftsartikel (refereegranskat)abstract
- A Ca2+-crosslinked wood-based nanofibrillated cellulose (NFC) hydrogel was investigated to build knowledge toward the use of nanocellulose for topical drug delivery applications in a chronic wound healing context. Proteins of varying size and isoelectric point were loaded into the hydrogel in a simple soaking procedure. The release of the proteins from the hydrogel was monitored and kinetics determining parameters of the release processes were assessed. The integrity of the hydrogel and proteins were also studied. The results showed that electrostatic interactions between the proteins and the negatively-charged NFC hydrogel structure played a central role in the loading process. The release of the proteins were governed by Fickian diffusion. An increased protein size, as well as a positive protein charge facilitated a slower and more sustained release process from the hydrogel matrix. At the same time, the positively-charged protein was shown to increase the post-loading hydrogel strength. Released proteins maintained structural stability and activity, thus indicating that the Ca2+-crosslinked NFC hydrogel could function as a carrier of therapeutic proteins without compromising protein function. It is foreseen that, by utilizing tunable charge properties of the NFC hydrogel, release profiles can be tailored to meet very specific treatment needs.
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| 9. |
- Blasi Romero, Anna
(författare)
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Bioactive nanocellulose materials for the treatment of chronic wounds
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Chronic wounds represent a burden for the healthcare system and significantly affect the quality of life of the patients. There is currently a lack of efficient treatments but new, improved therapeutic approaches are under development. Suggested innovative wound care therapies consist on the topical administration of bioactive compounds aimed at restoring the balance in the wound environment and promoting the healing. However, their effectiveness is limited due to the highly oxidative and proteolytic environment in the chronic wound. In the work presented in this thesis, a series of bioactive nanocellulose-based materials were developed with the aim of addressing some of the present demands in chronic wound care. Wood-derived cellulose nanofibrils (CNFs) were functionalized with selected bioactive molecules expected to endow CNFs with the ability to modulate the chronic wound environment. Different chemical approaches were explored to combine CNFs with the following biomolecules: the amino acid cysteine, the peptide oligoproline and the host defense peptide KR-12. Materials were characterized in terms of chemical structure, degree of substitution and bioactivity.The immobilization of cysteine onto CNFs (cys-CNF) provided the material with radical oxygen species (ROS) scavenging properties and the ability to inhibit protease activity, properties that were related to the presence of free thiol groups on the nanofibers. Storage conditions in an inert atmosphere or in the form of aerogel were proposed to assure the long-term activity of the cys-CNF material. Investigations on the use of the ROS-sensitive oligoproline to crosslink CNFs provided optimized protocols to maximize peptide substitution and the degree of crosslinking. The oligoproline-CNF materials were sensitive to ROS-mediated cleavage and provided a protective effect to cells exposed to oxidative conditions. Moreover, the feasibility of preparing ROS-responsive drug delivery hydrogels based on the oligoproline-CNF was demonstrated, with indications that tuning the length of the oligoproline peptide could be exploited to tailor the release rate of small proteins. CNF materials with antibacterial properties and the ability to modulate the response of pro-inflammatory macrophages were obtained by immobilizing KR-12 derivatives onto CNFs. This study highlighted the importance in the selection of the conjugation chemistry to preserve the activity of the peptide once immobilized. To conclude, this work has contributed with valuable strategies to develop bioactive CNF-based materials with the potential of paving the way for advanced solutions in the field of chronic wound care.
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| 10. |
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