Browsing by Subject "NANOCELLULOSE"

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  • Koivuniemi, Raili; Hakkarainen, Tiina; Kiiskinen, Jasmi; Kosonen, Mika; Vuola, Jyrki; Valtonen, Jussi; Luukko, Kari; Kavola, Heli; Yliperttula, Marjo (2020)
    Objective: Skin graft donor site management is a concern particularly for elderly patients and patients with poor wound healing competence, and also because donor sites are a source of pain and discomfort. Although different types of dressings exist, there is no consensus regarding optimal dressing type on donor site care to promote healing, reduce pain, and improve patients' comfort. Approach: This prospective, single-center clinical trial evaluated the performance of nanofibrillar cellulose (NFC) wound dressing (FibDex (R) by UPM-Kymmene Corporation) for treatment of donor sites compared with a polylactide-based copolymer dressing. The study enrolled 24 patients requiring skin grafting with mean age of 49 +/- 18. The primary outcome measure was wound healing time. Secondary outcomes, the epithelialization, subjective pain, the scar appearance assessed using the Patient and Observer Scar Assessment Scale (POSAS), and skin elasticity and transepidermal water loss (TEWL), were evaluated at 1 and 6 months postoperatively. Results: No statistically significant differences were observed between NFC and copolymer dressings regarding wound healing time, epithelialization, experience of pain, or TEWL. Significant differences were observed in the POSAS results for thickness and vascularity in the Observer score, in the favor of NFC over copolymer dressing. Moreover, skin elasticity was significantly improved with NFC dressing in terms of viscoelasticity and elastic modulus at 1 month postoperatively. Innovation: NFC dressing is a new, green sustainable product for wound treatment without animal or human-origin components. Conclusion: NFC dressing provides efficient wound healing at skin graft donor sites and is comparable or even preferable compared with the copolymer dressing.
  • Reyes, Guillermo; Lundahl, Meri; Alejandro-Martin, Serguei; Arteaga-Perez, Luis; Oviedo, Claudia; King, Alistair; Rojas, Orlando J. (2020)
    Hydrogels of TEMPO-oxidized nanocellulose were stabilized for dry-jet wet spinning using a shell of cellulose dissolved in 1,5-diazabicyclo[4.3.0]non-5-enium propionate ([DBNH][CO2Et]), a protic ionic liquid (PIL). Coagulation in an acidic water bath resulted in continuous core-shell filaments (CSFs) that were tough and flexible with an average dry (and wet) toughness of similar to 11 (2) MJ.m(-3) and elongation of similar to 9 (14) %. The CSF morphology, chemical composition, thermal stability, crystallinity, and bacterial activity were assessed using scanning electron microscopy with energy-dispersive X-ray spectroscopy, liquid-state nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermogravimetric analysis, pyrolysis gas chromatography-mass spectrometry, wide-angle X-ray scattering, and bacterial cell culturing, respectively. The coaxial wet spinning yields PIL-free systems carrying on the surface the cellulose II polymorph, which not only enhances the toughness of the filaments but facilities their functionalization.
  • Hassan, Ghada Ali Mohamed Saber; Forsman, Nina; Wan, Xing; Keurulainen, Leena; Bimbo, Luis M.; Johansson, Leena-Sisko; Sipari, Nina; Yli-Kauhaluoma, Jari Tapani; Zimmermann, Ralf; Stehl, Susanne; Werner, Carsten; Saris, Per E. J.; Österberg, Monika; Moreira, Vânia M. (2019)
    The design of antimicrobial surfaces as integral parts of advanced biomaterials is nowadays a high research priority, as the accumulation of microorganisms on surfaces inflicts substantial costs on the health and industry sectors. At present, there is a growing interest in designing functional materials from polymers abundant in nature, such as cellulose, that combine sustainability with outstanding mechanical properties and economic production. There is also the need to find suitable replacements for antimicrobial silver-based agents due to environmental toxicity and spread of resistance to metal antimicrobials. Herein we report the unprecedented decoration of cellulose nanofibril (CNF) films with dehydroabietylamine 1 (CNF-CMC-1), to give an innovative contact-active surface active against Gram-positive and Gram-negative bacteria including the methicillin-resistant S. aureus MRSA14TK301, with low potential to spread resistance and good biocompatibility, all achieved with low surface coverage. CNF-CMC-1 was particularly effective against S. aureus ATCC12528, causing virtually complete reduction of the total cells from 10(5) colony forming units (CFU)/mL bacterial suspensions, after 24 h of contact. This gentle chemical modification of the surface of CNF fully retained the beneficial properties of the original film, including moisture buffering and strength, relevant in many potential applications. Our originally designed surface represents a new class of ecofriendly biomaterials that optimizes the performance of CNF by adding antimicrobial properties without the need for environmentally toxic silver.
  • Carvalho, Tiago; Guedes, Gabriela; Sousa, Filipa L.; Freire, Carmen S. R.; Santos, Hélder A. (2019)
    Bacterial cellulose (BC) is a nanocellulose form produced by some nonpathogenic bacteria. BC presents unique physical, chemical, and biological properties that make it a very versatile material and has found application in several fields, namely in food industry, cosmetics, and biomedicine. This review overviews the latest state-of-the-art usage of BC on three important areas of the biomedical field, namely delivery systems, wound dressing and healing materials, and tissue engineering for regenerative medicine. BC will be reviewed as a promising biopolymer for the design and development of innovative materials for the mentioned applications. Overall, BC is shown to be an effective and versatile carrier for delivery systems, a safe and multicustomizable patch or graft for wound dressing and healing applications, and a material that can be further tuned to better adjust for each tissue engineering application, by using different methods.
  • Ajdary, Rubina; Zanjanizadeh Ezazi, Nazanin; Rebelo Correia, Alexandra Maria; Kemell, Marianna; Huan, Siqi; Ruskoaho, Heikki; Hirvonen, Jouni; Santos, Hélder A.; Rojas, Orlando J. (2020)
    A biomaterial system incorporating nanocellulose, poly(glycerol sebacate), and polypyrrole is introduced for the treatment of myocardial infarction. Direct ink writing of the multicomponent aqueous suspensions allows multifunctional lattice structures that not only feature elasticity and electrical conductivity but enable cell growth. They are proposed as cardiac patches given their biocompatibility with H9c2 cardiomyoblasts, which attach extensively at the microstructural level, and induce their proliferation for 28 days. Two model drugs (3i‐1000 and curcumin) are investigated for their integration in the patches, either by loading in the precursor suspension used for extrusion or by direct impregnation of the as‐obtained, dry lattice. In studies of drug release conducted for five months, a slow in vitro degradation of the cardiac patches is observed, which prevents drug burst release and indicates their suitability for long‐term therapy. The combination of biocompatibility, biodegradability, mechanical strength, flexibility, and electrical conductivity fulfills the requirement of the highly dynamic and functional electroresponsive cardiac tissue. Overall, the proposed cardiac patches are viable alternatives for the regeneration of myocardium after infarction through the effective integration of cardiac cells with the biomaterial.
  • Paukkonen, Heli; Kunnari, Mikko; Lauren, Patrick; Hakkarainen, Tiina; Auvinen, Vili-Veli; Oksanen, Timo; Koivuniemi, Raili; Yliperttula, Marjo; Laaksonen, Timo (2017)
    Concentrated 3% and 6.5% anionic nanofibrillar cellulose (ANFC) hydrogels were introduced as matrix reservoirs for controlled delivery applications of small molecules and proteins. A further aim was to study how the freeze-drying and subsequent rehydration of ANFC hydrogel affects the rheological properties and drug release of selected model compounds from the reconstructed hydrogels. It was demonstrated that the 3% and 6.5% ANFC hydrogels can be freeze-dried with suitable excipients into highly porous aerogel structures and redispersed back into the hydrogel form without significant change in the rheological properties. Freeze-drying did not affect the drug release properties from redispersed ANFC hydrogels, indicating that these systems could be stored in the dry form and only redispersed when needed. For large molecules, the diffusion coefficients were significantly smaller when higher ANFC fiber content was used, indicating that the amount of ANFC fibers in the hydrogel can be used to control the release rate. The release of small molecules was controlled with the ANFC fiber content only to a moderate extent. The results indicate that ANFC hydrogel can be used for controlled delivery of several types of molecules and that the hydrogel can be successfully freeze-dried and redispersed.
  • Lauren, Patrick; Somersalo, Petter; Pitkanen, Irina; Lou, Yan-Ru; Urtti, Arto; Partanen, Jouni; Seppala, Jukka; Madetoja, Mari; Laaksonen, Timo; Makitie, Antti; Yliperttula, Marjo (2017)
    Hydrogel nanomaterials, especially those that are of non-human and non-animal origins, have great potential in biomedical and pharmaceutical sciences due to their versatility and inherent soft-tissue like properties. With the ability to simulate native tissue function, hydrogels are potentially well suited for cellular therapy applications. In this study, we have fabricated nano-fibrillar cellulose-alginate (NFCA) suture coatings as biomedical devices to help overcome some of the limitations related to cellular therapy, such as low cell survivability and distribution out of target tissue. The addition of sodium alginate 8% (w/v) increased the NFCA hydrogel viscosity, storage and loss moduli by slightly under one order of magnitude, thus contributing significantly to coating strength. Confocal microscopy showed nearly 100% cell viability throughout the 2-week incubation period within and on the surface of the coating. Additionally, typical morphologies in the dual cell culture of spheroid forming HepG2 and monolayer type SK-HEP-1 were observed. Twelve out of 14 NFCA coated surgical sutures remained intact during the suturing operation with various mice and rat tissue; however, partial peeling off was observed in 2 of the coated sutures. We conclude that NFCA suture coatings could perform as cell-carrier systems for cellular based therapy and post-surgical treatment.
  • Garemark, Jonas; Perea-Buceta, Jesus Enrique; Rico del Cerro, Daniel; Hall, Stephen; Berke, Barbara; Kilpeläinen, Ilkka; Berglund, Lars; Li, Yuanyuan (2022)
    Eco-friendly materials with superior thermal insulation and mechanical properties are desirable for improved energy- and space-efficiency in buildings. Cellulose aerogels with structural anisotropy could fulfill these requirements, but complex processing and high energy demand are challenges for scaling up. Here we propose a scalable, nonadditive, top-down fabrication of strong anisotropic aerogels directly from wood with excellent, near isotropic thermal insulation functions. The aerogel was obtained through cell wall dissolution and controlled precipitation in lumen, using an ionic liquid (IL) mixture comprising DMSO and a guanidinium phosphorus-based IL [MTBD][MMP]. The wood aerogel shows a unique structure with lumen filled with nanofibrils network. In situ formation of a cellulosic nanofibril network in the lumen results in specific surface areas up to 280 m2/g and high yield strengths >1.2 MPa. The highly mesoporous structure (average pore diameter ∼20 nm) of freeze-dried wood aerogels leads to low thermal conductivities in both the radial (0.037 W/mK) and axial (0.057 W/mK) directions, showing great potential as scalable thermal insulators. This synthesis route is energy efficient with high nanostructural controllability. The unique nanostructure and rare combination of strength and thermal properties set the material apart from comparable bottom-up aerogels. This nonadditive synthesis approach is believed to contribute significantly toward large-scale design and structure control of biobased aerogels.
  • Niu, Xun; Liu, Yating; King, Alistair W. T.; Hietala, Sami; Pan, Hui; Rojas, Orlando J. (2019)
    Alternatives to petroleum-based plastics are of great significance not only from the point of view of their scientific and practical impact but to reduce the environmental footprint. Inspired by the composition and structure of wood's cell walls, we used phenolic acids to endow cellulosic fibers with new properties. The fiber dissolution and homogeneous modification were performed with a recyclable ionic liquid (IL) (tetrabutylammonium acetate ([N-4444][OAc]):dimethyl sulfoxide) to attain different levels of reaction activity for three phenolic acids (p-hydroxybenzoic acid, vanillic acid, and syringic acid). The successful autocatalytic Fischer esterification reaction was thoroughly investigated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, elemental analysis, and nuclear magnetic resonance spectroscopy (C-13-CP-MAS, diffusion-edited H-1 NMR and multiplicity-edited heteronuclear single quantum coherence). Control of the properties of cellulose in the dispersed state, welding, and IL plasticization were achieved during casting and recrystallization to the cellulose II crystalline allomorph. Films of cellulose carrying grafted acids were characterized with respect to properties relevant to packaging materials. Most notably, despite the low degree of esterification (DS <0.25), the films displayed a remarkable strength (3.5 GPa), flexibility (strains up to 35%), optical transparency (>90%), and water resistance (WCA similar to 90 degrees). Moreover, the measured water vapor barrier was found to be similar to that of poly(lactic acid) composite films. Overall, the results contribute to the development of the next-generation green, renewable, and biodegradable films for packaging applications.
  • Venäläinen, Salla H.; Hartikainen, Helinä (2018)
    Treatment of acidic mining water (MW) with industrial minerals and alkaline chemicals requires utilisation of unrenewable raw materials and produces disposable inorganic sludges of no further use. We investigated the efficiency of bio-based anionic nanofibrillated cellulose (NFC) to purify authentic MW high in metals and sulphate. In a short-term (10 min) adsorption experiment, highly acidic (pH 3.2) multi-metal process water was treated with anionic NFC gels differing in their consistency (1.1%, 1.4% and 1.8% wow) at three sorbent-to-solution ratios. To unravel the purification efficiency of the NFC gels, MW was treated stepwise with a set of fresh NFC gels in three sequential batches. Each treated solution was filtrated before pH measurement and analysis for the NFC-induced changes in the metal and sulphate concentrations. All NFC gels efficiently co-adsorbed metals and sulphate and decreased the acidity of MW. Depending on the dosage, a triplicated treatment with the NFC gels removed as much as 32-75% of metal cations and 34-75% of sulphate anions. The retention of metals highly exceeded the amount of carboxyl groups in the sorbent Thus, we concluded that, instead of electrostatic adsorption, the retention took place through formation of covalent metal-NFC complexes. The subsequent surplus in positive total charge formed on the NFC-surface, in turn, enabled electrostatic co-adsorption of sulphate anions. The mutual interactions between cellulose nanofibrils in the NFC gel weakened with decreasing consistency, which promoted the accessibility of the sorption sites. This improved the purification efficiency while decreasing the demand for cellulosic raw material. We concluded that anionic NFC could potentially serve as a multifunctional and resource-efficient purification agent in the treatment of acidic process waters of high ionic strength. Ideally, the elements retained could be liberated and recycled elsewhere. (C) 2018 Elsevier Ltd. All rights reserved.
  • Venäläinen, Salla H.; Hartikainen, Helinä (2017)
    We carried out an adsorption experiment to investigate the ability of anionic nanofibrillated cellulose (NFC) to retain metal and SO42- ions from authentic highly acidic (pH 3.2) mining water. Anionic NFC gels of different consistencies (1.1%, 1.4-% and 1.8-% w/w) were allowed to react for 10 min with mining water, after which NFC-induced changes in the metal and SO42- concentrations of the mining water were determined. The sorption capacities of the NFC gels were calculated as the difference between the element concentrations in the untreated and NFC-treated mining water samples. All the NFCs efficiently co-adsorbed both metals and SO42-. The retention of metals was concluded to take place through formation of metal-ligand complexes. The reaction between the NFC ligand and the polyvalent cations renders the cellulose nanofibrils positively charged and, thus, able to retain SO42- electrostatically. Adsorption capacity of the NFC gels substantially increased upon decreasing DM content as a result of the dilution-induced weakening of the mutual interactions between individual cellulose nanofibrils. This outcome reveals that the dilution of the NFC gel not only increases its purification capacity but also reduces the demand for cellulosic raw material. These results suggest that anionic NFC made of renewable materials serves as an environmentally sound and multifunctional purification agent for acidic multimetal mining waters or AMDs of high ionic strength. Unlike industrial minerals traditionally used to precipitate valuable metals from acidic mining effluents before their permanent disposal from the material cycle, NFC neither requires mining of unrenewable raw materials nor produces inorganic sludges. (C) 2017 Elsevier B.V. All rights reserved.
  • Agustin, Melissa B.; Mikkonen, Kirsi S.; Kemell, Marianna; Lahtinen, Panu; Lehtonen, Mari (2022)
    Pharmaceuticals are emerging water pollutants that pose a global threat to the sustainability and safety of aquatic resources. To mitigate their potential hazardous impacts, one of the keys is to address the removal of pharmaceutical residues from wastewaters. In this study, adsorption utilizing nanostructured wood-based adsorbents is viewed as a simple and versatile wastewater treatment method that can be adapted to remove pharmaceutical pollutants. To realize this potential, there is a need to understand the interaction of wood-based nanomaterials towards various types of pharmaceuticals. Thus, this study characterized and investigated the adsorption potential of the two common wood-based nanomaterials, the nanocelluloses and lignin nanoparticles (LNPs), towards various types of pharmaceuticals. The unmodified and cationized LNPs from hardwood and softwood lignin and nanocelluloses (TEMPO-oxidized cellulose nanofibrils (TCNF), cellulose and lignocellulose nanofibrils) were characterized for their morphology, zeta potential and surface charge density at different pHs. The adsorption capacity was determined from a multi-analyte adsorption system consisting of seven pharmaceuticals with different chemical characteristics (aromatic, non-aromatic, anionic, cationic, and neutral). Overall, the LNPs, with their polyaromatic structure, adsorbed a wider range of pharmaceuticals than the nanocelluloses. Among the nanocelluloses, the TCNF exhibited the highest adsorption capacity for cationic pharmaceuticals. Based on these findings, LNPs and TCNF are promising materials that can be combined to construct novel nanostructured adsorbents for pharmaceutical pollutants in water. The interaction of different pharmaceuticals with LNPs and nanocelluloses as revealed in this study can also be beneficial in other applications, such as drug encapsulation and release.