Composite chitosan and quaternary ammonium modified nanofibrillar cellulose anion exchange membranes for direct ethanol fuel cell applications

Fuel cells are a promising technology for energy production, but their commercialization is hindered mainly due to high costs. Direct alkaline ethanol fuel cells (DAFC) are receiving increasing attention as they can utilize cheaper, non-precious metal catalysts. A vital component of a DAFC is the anion exchange membrane (AEM). Currently, the commercially available AEMs don’t possess satisfactory properties. This indicates a need for the development of new highly efficient, environmentally friendly, and economically viable AEMs. Synthesis of synthetic polymer AEMs is usually complex and time-consuming, as well as environmentally unfriendly. Therefore, it is highly desired that the membrane material is bio-renewable, non-toxic and environmentally benign. In this work, a series of biopolymer membranes were designed by a simple, cost-effective, dispersion-casting procedure, fully complying with green-chemistry principles. Design of experiments was used as a methodology for identifying optimal combinations of influencing factors and their relations within selected responses. The obtained chitosan-Mg(OH)2 composite membranes containing modified nanofibrillar cellulose (CNF) fillers with quaternary ammonium groups were investigated for their mechanical properties, swelling ratio, ethanol permeability and ion exchange properties. Obtained data suggest the applicability of newly prepared, biopolymeric composites as eco-friendly AEMs in DAFC technologies.

A 3D Bioprinted Human Meniscus Shape Enriched with Mesenchymal Cells

Background and objectives: Regenerative medicine, with its massive development over the years, has the potential to solve some of the most problematic medical issues, such as functional organ transplantation. The aim of this study was to create a human meniscal shape 3D-printed enriched with human adipose-derived mesenchymal cells. Materials and Methods: Human infrapatellar fat pad was harvested, and mesenchymal cells were isolated. The mesenchymal stem cells were differentiated to the chondrocite lineage and a hydrogel (a nanofibrillar cellulose, sodium alginate, D-mannitol, and Hepes buffer solution combination) cell mixture was bioprinted to create three human-size meniscus structures. The obtained structures were evaluated regarding the cell viability, appropriate size in relation to a native meniscus, and some mechanical characteristics. Results: The human meniscal shape created respected the anatomic characteristic of a native structure. Cell viability of approximately 97% and extracellular matrix formation after the printing process were observed. The mean maximum force for the meniscus with mesenchymal cells was 6.5 N (+/−0.5 N) compared to the mean maximum force for the native meniscus of 10.32 N (+/−0.7 N), which is statistically relevant (p < 0.01). Conclusion: This paper presents the potential of bioprinting viable cell structures that could in the future present enough mechanical strength to replace a human organ, such as a meniscus. There are still limitations regarding the ink and the printing process, but we are confident that these problems will soon be solvable.

Human Biopsies in Nanofibrillar Cellulose Hydrogel – A Novel Method for Long-term Tissue Culture

Advanced 3D in vitro models are laborious to prepare and susceptible to unintentional design errors due to culture adaptations, cell immaturity, xenofactors or yet incomplete knowledge of the dynamics within tissues or materials. In order to acquire cost-efficient research material with intact in vivo composition, we developed novel tissue culture method with plant-derived scaffolding. Human skin-, foreskin- and glioblastoma multiforme biopsies were dissected mechanically and cultivated for 28 days in plant-derived nanofibrillar cellulose hydrogel. Comparative cultures were done using mouse sarcoma tumor-derived Matrigel. Long-term preservation of cultivated tissues was evaluated against typical immunohistochemical biomarkers for each tissue type: skin tissues for cytokeratins 5/6, E-cadherin and vimentin for sustained tissue structures, and brain neoplasia for Olig2, S100, Nestin, NOTCH1, MAP2 and GFAP for preserved disease profile. Histological analysis from both culture conditions showed that until day 28, all cultivated biopsy types were able to sustain their characteristic protein expressions without signs of necrosis. We here conclude a novel tissue culture model in xeno-free 3D scaffolding, that can enable long-term sample storage in vitro, studies of human tumor tissues and their non-neoplastic microenvironment, and innovations in personalized medicine research.

Comparison of the Therapeutic Effects of Native and Anionic Nanofibrillar Cellulose Hydrogels for Full-Thickness Skin Wound Healing

Nanofibrillar cellulose (NFC)-derived dressings such as films, hydrogels, and aerogels are one of the favorable materials for wound healing due to their proper mechanical properties and water holding ability. However, the therapeutic differences between native and anionic NFC materials are rarely studied. In this report, we compared the differences and addressed the regenerative potential of native and anionic wood-derived NFC hydrogels for wound treatment. In vitro characteristics of the hydrogels were detected using scanning electron microscopy, rheological measurements, and swelling and hemolytic activity assays. Skin regeneration at an early stage after hydrogel treatment was analyzed using an in vivo splinted excisional full-thickness skin wound model in C57BL/6 mice. Both native NFC and anionic NFC (ANFC) hydrogel with differing mechanical and surface properties were shown to be biocompatible. Surprisingly, wounds treated with NFC and ANFC hydrogel did not show any statistical difference compared with control wounds and progressed through normal wound closure, inflammatory response, re-epithelialization, vascularization, and tissue maturation with no signs of fibrosis. The data show here for the first time the therapeutic performance of native and anionic NFC hydrogel in a wound mimicking human wound healing mechanisms. The mechanical properties of native and anionic NFC hydrogels such as the capability to modify material stiffness may also prove to be valuable in the management of wounds in the future.

Testing of experimental samples of nanofibrillar cellulose in the production of lightweight coated paper

The influence of nanofibrillar cellulose samples on the coating compositions water retention is considered. It was shown that gels of nanofibrillar cellulose and coating compositions based on them are distinguished by a high water-retention capacity during centrifugation (50.8% and 31.0% versus 17.7% with NaCMC). A preliminary assessment of the printing and technical properties of light weight coated paper (LWC) using nanofibrillar cellulose in the coating composition has been carried out. The technical characteristics of nanofibrillar cellulose have been determined, formulations of lightweight paper coatings have been developed for high-speed modern equipment.

Electrical Stimulation of Adipose-Derived Stem Cells in 3D Nanofibrillar Cellulose Increases Their Osteogenic Potential

Due to the ageing population, there is a steadily increasing incidence of osteoporosis and osteoporotic fractures. As conventional pharmacological therapy options for osteoporosis are often associated with severe side effects, bone grafts are still considered the clinical gold standard. However, the availability of viable, autologous bone grafts is limited making alternative cell-based strategies a promising therapeutic alternative. Adipose-derived stem cells (ASCs) are a readily available population of mesenchymal stem/stromal cells (MSCs) that can be isolated within minimally invasive surgery. This ease of availability and their ability to undergo osteogenic differentiation makes ASCs promising candidates for cell-based therapies for bone fractures. Recent studies have suggested that both exposure to electrical fields and cultivation in 3D can positively affect osteogenic potential of MSCs. To elucidate the osteoinductive potential of a combination of these biophysical cues on ASCs, cells were embedded within anionic nanofibrillar cellulose (aNFC) hydrogels and exposed to electrical stimulation (ES) for up to 21 days. ES was applied to ASCs in 2D and 3D at a voltage of 0.1 V/cm with a duration of 0.04 ms, and a frequency of 10 Hz for 30 min per day. Exposure of ASCs to ES in 3D resulted in high alkaline phosphatase (ALP) activity and in an increased mineralisation evidenced by Alizarin Red S staining. Moreover, ES in 3D aNFC led to an increased expression of the osteogenic markers osteopontin and osteocalcin and a rearrangement and alignment of the actin cytoskeleton. Taken together, our data suggest that a combination of ES with 3D cell culture can increase the osteogenic potential of ASCs. Thus, exposure of ASCs to these biophysical cues might improve the clinical outcomes of regenerative therapies in treatment of osteoporotic fractures.