Browsing by Subject "Cellulose nanofibrils"

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  • Mertaniemi, Henrikki; Escobedo-Lucea, Carmen; Sanz-Garcia, Andres; Gandía, Carolina; Mäkitie, Antti; Partanen, Jouni; Ikkala, Olli; Yliperttula, Marjo (2016)
    Abstract Upon surgery, local inflammatory reactions and postoperative infections cause complications, morbidity, and mortality. Delivery of human adipose mesenchymal stem cells (hASC) into the wounds is an efficient and safe means to reduce inflammation and promote wound healing. However, administration of stem cells by injection often results in low cell retention, and the cells deposit in other organs, reducing the efficiency of the therapy. Thus, it is essential to improve cell delivery to the target area using carriers to which the cells have a high affinity. Moreover, the application of hASC in surgery has typically relied on animal-origin components, which may induce immune reactions or even transmit infections due to pathogens. To solve these issues, we first show that native cellulose nanofibers (nanofibrillated cellulose, NFC) extracted from plants allow preparation of glutaraldehyde cross-linked threads (NFC-X) with high mechanical strength even under the wet cell culture or surgery conditions, characteristically challenging for cellulosic materials. Secondly, using a xenogeneic free protocol for isolation and maintenance of hASC, we demonstrate that cells adhere, migrate and proliferate on the NFC-X, even without surface modifiers. Cross-linked threads were not found to induce toxicity on the cells and, importantly, hASC attached on NFC-X maintained their undifferentiated state and preserved their bioactivity. After intradermal suturing with the hASC decorated NFC-X threads in an ex vivo experiment, cells remained attached to the multifilament sutures without displaying morphological changes or reducing their metabolic activity. Finally, as NFC-X optionally allows facile surface tailoring if needed, we anticipate that stem-cell-decorated NFC-X opens a versatile generic platform as a surgical bionanomaterial for fighting postoperative inflammation and chronic wound healing problems.
  • Nugroho, Robertus Wahyu N.; Harjumäki, Riina; Zhang, Xue; Lou, Yan-Ru; Yliperttula, Marjo; Valle-Delgado, Juan Jose; Österberg, Monika (2019)
    Biomaterials of different nature have been and are widely studied for various biomedical applications. In many cases, biomaterial assemblies are designed to mimic biological systems. Although biomaterials have been thoroughly characterized in many aspects, not much quantitative information on the molecular level interactions between different biomaterials is available. That information is very important, on the one hand, to understand the properties of biological systems and, on the other hand, to develop new composite biomaterials for special applications. This work presents a systematic, quantitative analysis of self- and cross-interactions between films of collagen I (Col I), collagen IV (Col IV), laminin (LN-521), and cellulose nanofibrils (CNF), that is, biomaterials of different nature and structure that either exist in biological systems (e.g., extracellular matrices) or have shown potential for 3D cell culture and tissue engineering. Direct surface forces and adhesion between biomaterials-coated spherical micro-particles and flat substrates were measured in phosphate-buffered saline using an atomic force microscope and the colloidal probe technique. Different methods (Langmuir-Schaefer deposition, spin-coating, or adsorption) were applied to completely coat the flat substrates and the spherical micro particles with homogeneous biomaterial films. The adhesion between biomaterials films increased with the time that the films were kept in contact. The strongest adhesion was observed between Col IV films, and between Col IV and LN-521 films after 30 s contact time. In contrast, low adhesion was measured between CNF films, as well as between CNF and LN-521 films. Nevertheless, a good adhesion between CNF and collagen films (especially Col I) was observed. These results increase our understanding of the structure of biological systems and can support the design of new matrices or scaffolds where different biomaterials are combined for diverse biological or medical applications.
  • Riviere, Guillaume N.; Pion, Florian; Farooq, Muhammad; Sipponen, Mika H.; Koivula, Hanna; Jayabalan, Thangavelu; Pandard, Pascal; Marlair, Guy; Liao, Xun; Baumberger, Stephanie; Osterberg, Monika (2021)
    A "waste-valorization" approach was developed to transform recalcitrant hydrolysis lignin (HL) from secondgeneration bioethanol production into multifunctional bio-based products. The hydrolysis lignin (HL) was extracted with aqueous acetone, yielding two fractions enriched in lignin and cellulose, respectively. The soluble hydrolysis lignin (SHL) was converted into anionic and cationic colloidal lignin particles (CLPs and c-CLPs). The insoluble cellulose-rich fraction was transformed into lignocellulosic nanofibrils that were further combined with CLPs or c-CLPs to obtain nanocomposite films with tailored mechanical properties, oxygen permeability and antioxidant properties. To enable prospective applications of lignin in nanocomposite films and beyond, CLPs and c-CLPs were also produced from a soda lignin (SL) and the influence of the lignin type on the particle size and ecotoxicity was evaluated. Finally, the carbon footprint of the entire process from hydrolysis lignin to films was assessed and an integration to industrial scale was considered to reduce the energy consumption. While most previous work utilizes purified lignin and pristine and often purified cellulose fibers to produce nanomaterials, this work provides a proof of concept for utilizing the recalcitrant lignin-rich side stream of the bioethanol process as raw material for functional nanomaterials and renewable composites. (C) 2021 The Authors. Published by Elsevier B.V.
  • Lucenius, Jessica; Valle-Delgado, Juan José; Parikka, Kirsti; Österberg, Monika (2019)
    Plant-based polysaccharides (cellulose and hemicellulose) are a very interesting option for the preparation of sustainable composite materials to replace fossil plastics, but the optimum bonding mechanism between the hard and soft components is still not well known. In this work, composite films made of cellulose nanofibrils (CNF) and various modified and unmodified polysaccharides (galactoglucomannan, GGM; hydrolyzed and oxidized guar gum, GGhydHox; and guar gum grafted with polyethylene glycol, GG-g-PEG) were characterized from the nano- to macroscopic level to better understand how the interactions between the composite components at nano/microscale affect macroscopic mechanical properties, like toughness and strength. All the polysaccharides studied adsorbed well on CNF, although with different adsorption rates, as measured by quartz crystal microbalance with dissipation monitoring (QCM-D). Direct surface and friction force experiments using the colloidal probe technique revealed that the adsorbed polysaccharides provided repulsive forces–well described by a polyelectrolyte brush model – and a moderate reduction in friction between cellulose surfaces, which may prevent CNF aggregates during composite formation and, consequently, enhance the strength of dry films. High affinity for cellulose and moderate hydration were found to be important requirements for polysaccharides to improve the mechanical properties of CNF-based composites in wet conditions. The results of this work provide fundamental information on hemicellulose-cellulose interactions and can support the development of polysaccharide-based materials for different packaging and medical applications.