Improving some structural and biological characteristics of bacterial cellulose by cross‐linking

2021 ◽  
pp. 52056
Author(s):  
Sahar Abbasi Geravand ◽  
Ramin Khajavi ◽  
Mohammad Karim Rahimi ◽  
Manouchehr Shamsini Ghiyasvand ◽  
Amin Meftahi
Keyword(s):  
Bacterial Cellulose ◽  
Biological Characteristics ◽  
Cross Linking

scholarly journals Enzymatic and Chemical Cross-Linking of Bacterial Cellulose/Fish Collagen Composites—A Comparative Study

2021 ◽  
Vol 22 (7) ◽  
pp. 3346
Author(s):  
Agata Sommer ◽  
Paulina Dederko-Kantowicz ◽  
Hanna Staroszczyk ◽  
Sławomir Sommer ◽  
Marek Michalec
Keyword(s):  
Thermal Stability ◽  
Bacterial Cellulose ◽  
Secondary Alcohol ◽  
Water Vapor Permeability ◽  
Polymer Chains ◽  
Cross Linking ◽  
Vapor Permeability ◽  
Covalent Bonds ◽  
Fish Collagen ◽  
Chemical Cross Linking

This article compares the properties of bacterial cellulose/fish collagen composites (BC/Col) after enzymatic and chemical cross-linking. In our methodology, two transglutaminases are used for enzymatic cross-linking—one recommended for the meat and the other proposed for the fish industry—and pre-oxidated BC (oxBC) is used for chemical cross-linking. The structure of the obtained composites is characterized by scanning electron microscopy, thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy, and their functional properties by mechanical and water barrier tests. While polymer chains in uncross-linked BC/Col are intertwined by H-bonds, new covalent bonds in enzymatically cross-linked ones are formed—resulting in increased thermal stability and crystallinity of the material. The C2–C3 bonds cleavage in D-glucose units, due to BC oxidation, cause secondary alcohol groups to vanish in favor of the carbonyl groups’ formation, thus reducing the number of H-bonded OHs. Thermal stability and crystallinity of oxBC/Col remain lower than those of BC/Col. The BC/Col formation did not affect tensile strength and water vapor permeability of BC, but enzymatic cross-linking with TGGS improved them significantly.

Facile synthesis of bacterial cellulose fibres covalently intercalated with graphene oxide by one-step cross-linking for robust supercapacitors

2015 ◽  
Vol 3 (5) ◽  
pp. 1011-1017 ◽  
Author(s):  
Yun Liu ◽  
Jie Zhou ◽  
Enwei Zhu ◽  
Jian Tang ◽  
Xiaoheng Liu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Graphene Oxide ◽  
Bacterial Cellulose ◽  
Specific Capacitance ◽  
Cross Linking ◽  
Facile Synthesis ◽  
Cellulose Fibres ◽  
One Step

A novel 3D cross-linked BC/GO composite featuring a tensile strength of 18.48 MPa and a conductivity of 171 S m−1 shows 160 F g−1 mass-specific capacitance and 90.3% capacitance retention after 2000 cycles in supercapacitors.

An ultrathin bacterial cellulose membrane with a Voronoi-net structure for low pressure and high flux microfiltration

Nanoscale ◽  
2019 ◽  
Vol 11 (38) ◽  
pp. 17851-17859 ◽  
Author(s):  
Ning Tang ◽  
Shichao Zhang ◽  
Yang Si ◽  
Jianyong Yu ◽  
Bin Ding
Keyword(s):  
Bacterial Cellulose ◽  
Self Assembly ◽  
High Performance ◽  
Low Pressure ◽  
Cross Linking ◽  
Cellulose Membrane ◽  
High Flux ◽  
Bacterial Cellulose Membrane ◽  
Evaporation Induced Self Assembly ◽  
Chemical Cross Linking

A BC membrane with a stable Voronoi-like nanonet layer was prepared by evaporation-induced self-assembly and chemical cross-linking for high performance microfiltration.

scholarly journals Fast-Growing Bacterial Cellulose with Outstanding Mechanical Properties via Cross-Linking by Multivalent Ions

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2838
Author(s):  
Andrea Knöller ◽  
Marc Widenmeyer ◽  
Joachim Bill ◽  
Zaklina Burghard
Keyword(s):  
Growth Rate ◽  
Bacterial Cellulose ◽  
Flexible Electronics ◽  
Large Scale ◽  
High Strength ◽  
Fold Increase ◽  
Cross Linking ◽  
Slow Growth Rate ◽  
Order Of Magnitude ◽  
Cellulose Membranes

Bacterial cellulose is an organic product of certain bacterias’ metabolism. It differs from plant cellulose by exhibiting a high strength and purity, making it especially interesting for flexible electronics, membranes for water purification, tissue engineering for humans or even as artificial skin and ligaments for robotic devices. However, bacterial cellulose’s naturally slow growth rate has limited its large-scale applicability to date. Titanium (IV) bis-(ammonium lactato) dihydroxide is shown to be a powerful tool to boost the growth rate of bacterial cellulose production by more than one order of magnitude and that it simultaneously serves as a precursor for the Ti4+-coordinated cross-linking of the fibers during membrane formation. The latter results in an almost two-fold increase in Young’s modulus (~18.59 GPa), a more than three-fold increase in tensile strength (~436.70 MPa) and even a four-fold increase in toughness (~6.81 MJ m−³), as compared to the pure bacterial cellulose membranes.

scholarly journals The Impact of Cross-linking Mode on the Physical and Antimicrobial Properties of a Chitosan/Bacterial Cellulose Composite

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 491 ◽  
Author(s):  
Jun Liang ◽  
Rui Wang ◽  
Ruipeng Chen
Keyword(s):  
Bacterial Cellulose ◽  
Composite Films ◽  
Antimicrobial Properties ◽  
Chitosan Film ◽  
Surface Hydrophobicity ◽  
Cross Linking ◽  
Cellulose Films ◽  
Antimicrobial Efficiency ◽  
The Matrix ◽  
The Impact

The bacteriostatic performance of a chitosan film is closely related to its ionic and physical properties, which are significantly influenced by the mode of cross-linking. In the current work, chitosan with or without bacterial cellulose was cross-linked with borate, tripolyphosphate, or the mixture of borate and tripolyphosphate, and the composite films were obtained by a casting of dispersion. Mechanical measurements indicated that different modes of cross-linking led to varying degrees of film strength and elongation increases, while the films treated with the borate and tripolyphosphate mixture showed the best performance. Meanwhile, changes in the fractured sectional images showed a densified texture induced by cross-linkers, especially for the borate and tripolyphosphate mixture. Measurements of Fourier transform infrared showed the enhanced interaction between the matrix polymers treated by borate, confirmed by a slight increase in the glass transitional temperature and a higher surface hydrophobicity. However, the reduced antimicrobial efficiency of composite films against E. coli, B. cinerea, and S. cerevisiae was obtained in cross-linked films compared with chitosan/bacterial cellulose films, indicating that the impact on the antimicrobial function of chitosan is a noteworthy issue for cross-linking.

scholarly journals Effect of Iron-Oxide Nanoparticles Impregnated Bacterial Cellulose on Overall Properties of Alginate/Casein Hydrogels: Potential Injectable Biomaterial for Wound Healing Applications

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2690
Author(s):  
Rahul Patwa ◽  
Oyunchimeg Zandraa ◽  
Zdenka Capáková ◽  
Nabanita Saha ◽  
Petr Sáha
Keyword(s):  
Wound Healing ◽  
Magnetic Properties ◽  
Bacterial Cellulose ◽  
Chemical Properties ◽  
Microscopic Analysis ◽  
Cross Linking ◽  
Mechanical Compression ◽  
Physico Chemical ◽  
Cytotoxicity Studies ◽  
Migration Of Cells

In this study we report the preparation of novel multicomponent hydrogels as potential biomaterials for injectable hydrogels comprised of alginate, casein and bacterial cellulose impregnated with iron nanoparticles (BCF). These hydrogels demonstrated amide cross-linking of alginate–casein, ionic cross-linking of alginate and supramolecular interaction due to incorporation of BCF. Incorporation of BCF into the hydrogels based on natural biopolymers was done to reinforce the hydrogels and impart magnetic properties critical for targeted drug delivery. This study aimed to improve overall properties of alginate/casein hydrogels by varying the BCF loading. The physico-chemical properties of gels were characterized via FTIR, XRD, DSC, TGA, VSM and mechanical compression. In addition, swelling, drug release, antibacterial activity and cytotoxicity studies were also conducted on these hydrogels. The results indicated that incorporation of BCF in alginate/casein hydrogels led to mechanically stronger gels with magnetic properties, increased porosity and hence increased swelling. A porous structure, which is essential for migration of cells and biomolecule transportation, was confirmed from microscopic analysis. The porous internal structure promoted cell viability, which was confirmed through MTT assay of fibroblasts. Moreover, a hydrogel can be useful for the delivery of essential drugs or biomolecules in a sustained manner for longer durations. These hydrogels are porous, cell viable and possess mechanical properties that match closely to the native tissue. Collectively, these hybrid alginate–casein hydrogels laden with BCF can be fabricated by a facile approach for potential wound healing applications.

Influence of Calcium Ions on the Plant Cell Surface: Membrane Fusions and Conformational Changes

1974 ◽  
Vol 32 ◽  
pp. 154-155
Author(s):  
D. James Morré ◽  
Charles E. Bracker ◽  
William J. VanDerWoude
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Conformational Changes ◽  
Calcium Ions ◽  
Surface Membrane ◽  
Carboxyl Groups ◽  
Cross Linking ◽  
Ultrastructural Evidence ◽  
Glycine Max L ◽  
Wall Extensibility

Calcium ions in the concentration range 5-100 mM inhibit auxin-induced cell elongation and wall extensibility of plant stems. Inhibition of wall extensibility requires that the tissue be living; growth inhibition cannot be explained on the basis of cross-linking of carboxyl groups of cell wall uronides by calcium ions. In this study, ultrastructural evidence was sought for an interaction of calcium ions with some component other than the wall at the cell surface of soybean (Glycine max (L.) Merr.) hypocotyls.

Embedding Procedure for Water Swollen Samples

1970 ◽  
Vol 28 ◽  
pp. 504-505
Author(s):  
Ann M. Thomas ◽  
Virginia Shemeley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Exchange ◽  
Structural Changes ◽  
Cross Linking ◽  
Ion Exchange Resins ◽  
Transmission Electron ◽  
First Pass ◽  
Exchange Resins

Those samples which swell rapidly when exposed to water are, at best, difficult to section for transmission electron microscopy. Some materials literally burst out of the embedding block with the first pass by the knife, and even the most rapid cutting cycle produces sections of limited value. Many ion exchange resins swell in water; some undergo irreversible structural changes when dried. We developed our embedding procedure to handle this type of sample, but it should be applicable to many materials that present similar sectioning difficulties.The purpose of our embedding procedure is to build up a cross-linking network throughout the sample, while it is in a water swollen state. Our procedure was suggested to us by the work of Rosenberg, where he mentioned the formation of a tridimensional structure by the polymerization of the GMA biproduct, triglycol dimethacrylate.

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