| 1. |
- Aimonen, Kukka, et al.
(author)
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Role of Surface Chemistry in the In Vitro Lung Response to Nanofibrillated Cellulose
- 2021
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In: Nanomaterials. - : MDPI. - 2079-4991. ; 11:2
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Journal article (peer-reviewed)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. |
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| 3. |
- Arnell, Robert, et al.
(author)
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Analytical Characterization of Chiral Drug-Protein Interactions: Comparison between the Optical Biosensor (Surface Plasmon Resonance) Assay and the HPLC Perturbation Method
- 2006
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In: Analytical Chemistry. ; 78:5, s. 1682-1689
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Journal article (peer-reviewed)abstract
- Two modern, fundamentally different methods were used for a detailed investigation of enantioselective drug-protein interactions, a surface plasmon resonance (SPR)-based Biacore 2000 biosensor assay and the previously validated HPLC perturbation method (HPLC-PM). This is the first time SPR has been used for this purpose. The fundamental features of the two methods were investigated, and the consequences for operation and data evaluation were addressed. With HPLC-PM, chiral data could be obtained directly from the racemic mixture, whereas a separate analysis of each pure enantiomer was required to obtain chiral data with SPR. It was shown that if chirality is not attributed in the SPR analysis, misleading average racemic binding constants will be obtained. Both drug and protein consumption were considerably higher with HPLC-PM. HPLC-PM was found to be best suited for measurements of weak affinity interactions, whereas the SPR method was best for strong interactions. With both methods, the presence of DMSO in the samples severely affected the interactions, introducing errors. The binding of the -blockers alprenolol and propranolol to Cel7a cellulase was used as a model system. These methods gave results that agreed quite well qualitatively, but considerable quantitative deviations were sometimes obtained.
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| 4. |
- Basu, Alex, et al.
(author)
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Hemocompatibility of Ca2+-Crosslinked Nanocellulose Hydrogels : Toward Efficient Management of Hemostasis
- 2017
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In: Macromolecular Bioscience. - : Wiley. - 1616-5187 .- 1616-5195. ; 17:11
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Journal article (peer-reviewed)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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| 5. |
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| 6. |
- Basu, Alex, et al.
(author)
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In Vitro and in Vivo Evaluation of the Wound Healing Properties of Nanofibrillated Cellulose Hydrogels
- 2018
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In: ACS Applied Bio Materials. - : American Chemical Society (ACS). - 2576-6422. ; 1:6, s. 1853-1863
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Journal article (peer-reviewed)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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| 7. |
- Basu, Alex
(author)
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Ion-Crosslinked Nanocellulose Hydrogels for Advanced Wound Care Applications
- 2018
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Doctoral thesis (other academic/artistic)abstract
- A current trend in the field of wound care is the development of wound healing materials that are designed to address specific types of wounds or underlying pathologies to achieve improved healing. At the same time, there is a societal drive to replace synthetic materials with renewable alternatives. The work presented in this thesis was therefore carried out to investigate the use of wood nanocellulose, produced from the world’s most abundant biopolymer, cellulose, in advanced wound care applications.Wood-based nanofibrillated cellulose (NFC) was chemically functionalized and crosslinked using calcium to obtain a self-standing hydrogel. The NFC hydrogel was evaluated in terms of its physicochemical properties, biocompatibility, blood interactions, bacterial interactions, in vivo wound healing ability and, finally, as a protein carrier. Parallel with the assessment of the NFC hydrogel, modified versions of the material were tested to investigate the tunability of the above-mentioned characteristics.The ability of the hydrogel to maintain a moist wound bed was demonstrated. Evaluation of the biocompatibility showed that the material was cytocompatible and did not trigger inflammatory mechanisms. Furthermore, the NFC hydrogel supported cell proliferation, and was shown to possess hemostatic properties. It was also discovered that the material had a slight bacteriostatic effect and the ability to act as a barrier against bacteria. When tested in vivo, the hydrogel was found to significantly improve wound healing.Modifications through the incorporation of additives to the hydrogel matrix, as well as exchange of the crosslinking ion, were shown to influence the biological response to the material. Moreover, the results presented here demonstrate the possibility of using the NFC hydrogel as a protein carrier; the easily adjustable charge property being identified as a central parameter for manipulation to regulate the release profile.In conclusion, this work has demonstrated the extensive wound healing ability of the calcium-crosslinked NFC hydrogel, and represents an important milestone in the research on NFC towards advanced wound care applications. It is expected that the easily modifiable nature of the material can be exploited to further develop the NFC hydrogel to suit the treatment needs for a broad range of wound types.
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| 9. |
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| 10. |
- Basu, Alex, et al.
(author)
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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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In: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 181, s. 345-350
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Journal article (peer-reviewed)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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