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Chen SQ, Meldrum OW, Liao Q, Li Z, Cao X, Guo L, Zhang S, Zhu J, Li L. The influence of alkaline treatment on the mechanical and structural properties of bacterial cellulose. Carbohydr Polym 2021; 271:118431. [PMID: 34364571 DOI: 10.1016/j.carbpol.2021.118431] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 07/06/2021] [Accepted: 07/08/2021] [Indexed: 10/20/2022]
Abstract
The unique mechanical properties of hydrated bacterial cellulose make it suitable for biomedical applications. This study evaluates the effect of concentrated sodium hydroxide treatment on the structural and mechanical properties of bacterial cellulose hydrogels using rheological, tensile, and compression tests combined with mathematical modelling. Bacterial cellulose hydrogels show a concentration-dependent and irreversible reduction in shear moduli, compression, and tensile strength after alkaline treatment. Applying a poroelastic biphasic model to through-thickness compressive stress-relaxation tests showed the alkaline treatment to induce no significant change in axial compression, an effect was observed in the radial direction, potentially due to the escape of water from within the hydrogel. Scanning electron microscopy showed a more porous structure of bacterial cellulose. These results show how concentration-dependent alkaline treatment induces selective weakening of intramolecular interactions between cellulose fibres, allowing the opportunity to precisely tune the mechanical properties for specific biomedical application, e.g., faster-degradable materials.
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Affiliation(s)
- Si-Qian Chen
- Key Laboratory of Healthy Food Development and Nutrition Regulation of China National Light Industry, School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan 523808, PR China
| | - Oliver W Meldrum
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore
| | - Qiudong Liao
- Key Laboratory of Healthy Food Development and Nutrition Regulation of China National Light Industry, School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan 523808, PR China; College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Zhaofeng Li
- Key Laboratory of Healthy Food Development and Nutrition Regulation of China National Light Industry, School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan 523808, PR China; School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Xiao Cao
- Key Laboratory of Healthy Food Development and Nutrition Regulation of China National Light Industry, School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan 523808, PR China
| | - Lei Guo
- The School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Shuyan Zhang
- Key Laboratory of Healthy Food Development and Nutrition Regulation of China National Light Industry, School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan 523808, PR China
| | - Jie Zhu
- Key Laboratory of Healthy Food Development and Nutrition Regulation of China National Light Industry, School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan 523808, PR China.
| | - Lin Li
- Key Laboratory of Healthy Food Development and Nutrition Regulation of China National Light Industry, School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan 523808, PR China.
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Influence of Drying Method and Argon Plasma Modification of Bacterial Nanocellulose on Keratinocyte Adhesion and Growth. NANOMATERIALS 2021; 11:nano11081916. [PMID: 34443747 PMCID: PMC8398638 DOI: 10.3390/nano11081916] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/16/2021] [Accepted: 07/23/2021] [Indexed: 12/05/2022]
Abstract
Due to its nanostructure, bacterial nanocellulose (BC) has several advantages over plant cellulose, but it exhibits weak cell adhesion. To overcome this drawback, we studied the drying method of BC and subsequent argon plasma modification (PM). BC hydrogels were prepared using the Komagataeibacter sucrofermentans (ATCC 700178) bacteria strain. The hydrogels were transformed into solid samples via air-drying (BC-AD) or lyophilization (BC-L). The sample surfaces were then modified by argon plasma. SEM revealed that compared to BC-AD, the BC-L samples maintained their nanostructure and had higher porosity. After PM, the contact angle decreased while the porosity increased. XPS showed that the O/C ratio was higher after PM. The cell culture experiments revealed that the initial adhesion of human keratinocytes (HaCaT) was supported better on BC-L, while the subsequent growth of these cells and final cell population density were higher on BC-AD. The PM improved the final colonization of both BC-L and BC-AD with HaCaT, leading to formation of continuous cell layers. Our work indicates that the surface modification of BC renders this material highly promising for skin tissue engineering and wound healing.
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Li Z, Chen SQ, Cao X, Li L, Zhu J, Yu H. Effect of pH Buffer and Carbon Metabolism on the Yield and Mechanical Properties of Bacterial Cellulose Produced by Komagataeibacter hansenii ATCC 53582. J Microbiol Biotechnol 2021; 31:429-438. [PMID: 33323677 PMCID: PMC9705897 DOI: 10.4014/jmb.2010.10054] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/30/2020] [Accepted: 12/14/2020] [Indexed: 12/15/2022]
Abstract
Bacterial cellulose (BC) is widely used in the food industry for products such as nata de coco. The mechanical properties of BC hydrogels, including stiffness and viscoelasticity, are determined by the hydrated fibril network. Generally, Komagataeibacter bacteria produce gluconic acids in a glucose medium, which may affect the pH, structure and mechanical properties of BC. In this work, the effect of pH buffer on the yields of Komagataeibacter hansenii strain ATCC 53582 was studied. The bacterium in a phosphate and phthalate buffer with low ionic strength produced a good BC yield (5.16 and 4.63 g/l respectively), but there was a substantial reduction in pH due to the accumulation of gluconic acid. However, the addition of gluconic acid enhanced the polymer density and mechanical properties of BC hydrogels. The effect was similar to that of the bacteria using glycerol in another carbon metabolism circuit, which provided good pH stability and a higher conversion rate of carbon. This study may broaden the understanding of how carbon sources affect BC biosynthesis.
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Affiliation(s)
- Zhaofeng Li
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P.R. China,School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan 523808, P.R. China,Key Laboratory of Healthy Food Development and Nutrition Regulation of China National Light Industry, Dongguan University of Technology, Dongguan 523808, P.R. China
| | - Si-Qian Chen
- School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan 523808, P.R. China,Key Laboratory of Healthy Food Development and Nutrition Regulation of China National Light Industry, Dongguan University of Technology, Dongguan 523808, P.R. China,Institute of Science and Technology Innovation, Dongguan University of Technology, Dongguan 523808, P.R. China
| | - Xiao Cao
- Key Laboratory of Healthy Food Development and Nutrition Regulation of China National Light Industry, Dongguan University of Technology, Dongguan 523808, P.R. China,Institute of Science and Technology Innovation, Dongguan University of Technology, Dongguan 523808, P.R. China
| | - Lin Li
- School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan 523808, P.R. China,Key Laboratory of Healthy Food Development and Nutrition Regulation of China National Light Industry, Dongguan University of Technology, Dongguan 523808, P.R. China,Institute of Science and Technology Innovation, Dongguan University of Technology, Dongguan 523808, P.R. China
| | - Jie Zhu
- School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan 523808, P.R. China,Key Laboratory of Healthy Food Development and Nutrition Regulation of China National Light Industry, Dongguan University of Technology, Dongguan 523808, P.R. China,Institute of Science and Technology Innovation, Dongguan University of Technology, Dongguan 523808, P.R. China,Corresponding authors J. Zhu Phone: +86-769-22862195 Fax: +86-769-22861680 E-mail:
| | - Hongpeng Yu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P.R. China,H. Yu E-mail:
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