Oxidised cellulose

Hydrogels derived from TEMPO-oxidised cellulose nanofibrils (TOCNs) are not robust and inherently water unstable if the TOCNs are not crosslinked or coated with a water-swellable polymer. Furthermore, the manufacturing of self-standing TOCN films is still a challenge due to the small TOCN diameter and the viscosifying effect of TOCNs. Here, we report the TEMPO-mediated oxidation of bacterial cellulose (BC) nanopaper as a route to produce robust and water stable TOCN hydrogels without the need of additional additives or crosslinking steps...

This research explains the one-pot process of cellulose fibrillation to procure nanocellulose fibres and water-soluble oxidised cellulose using iron oxide catalysts with hydrogen peroxide. The process involved three stages. First, cellulose underwent depolymerisation to form nanocellulose fibres. Second, nanocellulose was oxidised to a water-soluble product, and the final stage was the complete decomposition. Factors such as the valency of ions in the crystal lattice of catalyst, its particle size, and reaction time influenced the treatment...

BACKGROUND: Elevated protease activity is a characteristic feature of chronic wounds, where the inflammatory phase of wound healing is prolonged. The choice of dressings in treatment of chronic wounds can change the nature of the wound base and have a significant impact on healing. OBJECTIVE: To evaluate the impact of oxidised regenerated cellulose/collagen dressings on Staphylococcal-mediated protease activity in an inflamed wound model. METHODS: We developed an in vitro 3D inflamed wound model, and simulated inflammation by exposing the models to Staphylococcal spent culture supernatant...

Mineral coatings manipulate surface properties such as roughness, porosity, wettability and surface energy. Properties that are known to determine cell behaviour. Therefore, mineral coatings can potentially be used to manipulate cell fate. This paper studies mineral-cell interactions through coatings in a stacked cell culture platform. Minerals were chosen according to their influence on Human Dermal Fibroblasts (HDFs): calcium carbonate, calcium sulphates, and kaolin. Mineral coatings were formulated with the additives latex, sorbitol, polyvinyl alcohol (PVOH) and TEMPO-oxidised cellulose nanofibrils (CNF-T)...

The retrospective pragmatic real-world data (RWD) study compared the healing outcomes of diabetic foot ulcers (DFUs) treated with either ovine forestomach matrix (OFM) (n = 1150) or collagen/oxidised regenerated cellulose (ORC) (n = 1072) in out-patient wound care centres. Median time to wound closure was significantly (P = .0015) faster in the OFM group (14.6 ± 0.5 weeks) relative to the collagen/ORC group (16.4 ± 0.7). A sub-group analysis was performed to understand the relative efficacy in DFUs requiring longer periods of treatment and showed that DFUs treated with OFM healed up to 5...

Lytic polysaccharide monooxygenase (LPMO) are mono‑copper enzymes known for the oxidative cleavage of recalcitrant polysaccharides with their intriguing and unique catalytic chemistry. Such impeccable oxidation potential has made them highly valuable in the enzymatic consortia for the degradation of ligno-cellulosic biomass. Bioinformatic analysis has revealed an unannotated LPMO gene in the genome of A. oryzae. Multiple sequence alignment showed the presence of conserved "histidine brace" of LPMO in the amino acid sequence of the enzyme...

This study aimed to quantify the influence of clays and partially oxidised cellulose nanofibrils (OCNF) on gelation as well as characterise their physical and chemical interactions. Mixtures of Laponite and montmorillonite clays with OCNF form shear-thinning gels that are more viscous across the entire shear range than OCNF on its own. Viscosity and other rheological properties can be fine-tuned using different types of clay at different concentrations (0.5-2 wt%). Laponite particles are an order of magnitude smaller than those of montmorillonite (radii of 150 Å compared to 2000 Å) and are therefore able to facilitate networking of the cellulose fibrils, resulting in stronger effects on rheological properties including greater viscosity...

Oxidised regenerated cellulose (ORC)/collagen dressings help maintain physiologically moist wound environments conducive to wound healing. While evidence supporting ORC/collagen dressing use exists, comprehensive assessment is needed. This systematic review/meta-analysis evaluated the performance of ORC/collagen dressings compared with standard dressings. A systematic literature search was performed using PUBMED, EMBASE, and QUOSA Virtual Library. Published studies and conference abstracts were assessed between 1 January 1996 and 27 July 2020...

Oxidative plant cell-wall processing enzymes are of great importance in biology and biotechnology. Yet, our insight into the functional interplay amongst such oxidative enzymes remains limited. Here, a phylogenetic analysis of the auxiliary activity 7 family (AA7), currently harbouring oligosaccharide flavo-oxidases, reveals a striking abundance of AA7-genes in phytopathogenic fungi and Oomycetes. Expression of five fungal enzymes, including three from unexplored clades, expands the AA7-substrate range and unveils a cellooligosaccharide dehydrogenase activity, previously unknown within AA7...

Water quality parameters such as salt content and various pH environments can alter the stability of gels as well as their rheological properties. Here, we investigated the effect of various concentrations of NaCl and different pH environments on the rheological properties of TEMPO-oxidised cellulose nanofibril (OCNF) and starch-based hydrogels. Addition of NaCl caused an increased stiffness of the OCNF:starch (1:1 wt%) blend gels, where salt played an important role in reducing the repulsive OCNF fibrillar interactions...

BACKGROUND: Lytic polysaccharide monooxygenases (LPMOs) are important industrial enzymes known for their catalytic degradation of recalcitrant polymers such as cellulose or chitin. Their activity can be measured by lengthy HPLC methods, while high-throughput methods are less specific. A fast and specific LPMO assay would simplify screening for new or engineered LPMOs and accelerate biochemical characterization. RESULTS: A novel LPMO activity assay was developed based on the production of the dye phenolphthalein (PHP) from its reduced counterpart (rPHP)...

Many features that are appropriate for an ideal tissue engineered biomaterial are found in plant tissues. Hierarchically organized Bambusa vulgaris exhibits structural similarities to native bone, but the degradation of cellulose that is the main component of the plant cell wall is a challenge. In this study, Bamboo stem was subjected to decellularization followed by a chemical oxidation process (treated with sodium periodate) to enhance biocompatibility and biodegradation. The crystallinity of oxidised plant scaffolds was reduced, resulting in lower mechanical strength...

OBJECTIVE: To compare the efficacy and safety of HemoStyp (United Health Products, US), a neutralised oxidised regenerated cellulose (NORC) and Surgicel (Johnson & Johnson, US), an oxidised regenerated cellulose (ORC), in the management of bleeding of surgical wounds during abdominal, thoracic and vascular surgeries. METHOD: This study was a prospective, non-inferiority, multicentre, randomised, open-label trial. Surgical procedures were performed according to expected standard of care and in compliance with all relevant laws and institutional guidelines...

This study was conducted to develop biodegradable cellulose scaffolds by oxidising porous cellulose sponges for tissue engineering applications. Cellulose powder was dissolved in ionic liquid using a salt leaching method, and porous cellulose scaffolds of various pore sizes were prepared. The scaffolds were oxidised with periodate to introduce aldehyde at a rate controlled by the periodate concentration. Oxidised scaffolds exhibited weight loss in cell culture medium, but not in phosphate buffer. Therefore, we confirmed that Schiff base formation between the aldehyde and amino groups through a Maillard reaction triggered cellulose molecular degradation...

The rheological behaviour of aqueous suspensions of lignocellulose nanofibrils (LCNF) is investigated systematically by considering the coupled effect of residual lignin and LCNF morphology. The LCNF was obtained by high-energy fluidisation of TEMPO oxidised mechanical fibres followed by size fractionation (fibril width of ~5, ~9, and ~18 nm). Nanofibril width and corresponding fibril-fibril interactions are strongly influenced by the presence and distribution of lignin in the respective fractions, either retained on the fibril surface or as free structures present in the finest size fraction...

INTRODUCTION: Despite ongoing optimisation of surgical techniques, hemostasis continues to be a fundamental challenge in many operations today. This randomised controlled trial compared the efficacy of a new hemostatic agent made of oxidised regenerated cellulose and collagen (ORC-Coll) with that of a conventional carrier-bound fibrin sealant (CBFS). METHODS: Hemostasis was investigated representatively in the case of post-thyroidectomy bleeding from the resection surface...

TEMPO and periodate are combined in a one-shot reaction to oxidise cellulose and produce nanocellulose gels with a wide range of degree of substitution (DS). Highly-oxidised cellulose nanofibres with a high charge of -80 mV were produced. The strong electrical repulsion between TEMPO-periodate oxidised nanofibres (TPOF) results in the formation of well-separated nanofibres with a diameter of 2-4 nm, albeit depolymerised due to high oxidation. TPOF produces highly-transparent gels due to smaller aspect ratio and high surface charge...

Photoluminescence of cellulose, and other polysaccharides, has long been presumed to be due to contamination of the material by other autofluorescent compounds - such as lignin, or proteins. This is attributed to the lack of known fluorescent chemical groups present in the molecular structure of polysaccharides and the weak emission intensity when compared to typical fluorophores. However, recent research suggests that the observed luminescence may actually be due to transitions involving the n orbitals containing lone electron pairs present in oxyl groups, stabilised by the molecular forces between the polysaccharide chains...

We present the case of a 14 year old who underwent laparoscopic marsupialisation of a splenic cyst. Postoperative ultrasound demonstrated an echogenic collection in the surgical bed that was initially misdiagnosed as an infected collection/abscess due to its sonographic appearances but was finally correctly identified as haemostatic material that had been packed into the surgical cavity. We subsequently constructed a tissue phantom containing a compressed ball of SURGICEL (r) Absorbable Hemostat and demonstrated that it showed identical sonographic appearances...

Intermediate-level radioactive waste (ILW) includes cellulosic materials, which under the hyperalkaline conditions expected in a cementitious geological disposal facility (GDF), will undergo abiotic hydrolysis forming a variety of soluble organic species. Isosaccharinic acid (ISA) is a notable hydrolysis product, being a strong metal complexant that may enhance the transport of radionuclides to the biosphere. This study shows that irradiation with 1 MGy of γ-radiation under hyperalkaline conditions enhances the rate of ISA production from alkali hydrolysis of cellulose, indicating that radionuclide mobilisation to the biosphere may occur faster than previously anticipated...