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11 pages, 3350 KiB

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Electrochemical Glue for Binding Chitosan–Alginate Hydrogel Fibers for Cell Culture

by Yoshinobu Utagawa, Kosuke Ino, Tatsuki Kumagai, Kaoru Hiramoto, Masahiro Takinoue, Yuji Nashimoto and Hitoshi Shiku

Micromachines 2022, 13(3), 420; https://doi.org/10.3390/mi13030420 - 8 Mar 2022

Cited by 7 | Viewed by 5040

Abstract

Three-dimensional organs and tissues can be constructed using hydrogels as support matrices for cells. For the assembly of these gels, chemical and physical reactions that induce gluing should be induced locally in target areas without causing cell damage. Herein, we present a novel electrochemical strategy for gluing hydrogel fibers. In this strategy, a microelectrode electrochemically generated HClO or Ca²⁺, and these chemicals were used to crosslink chitosan–alginate fibers fabricated using interfacial polyelectrolyte complexation. Further, human umbilical vein endothelial cells were incorporated into the fibers, and two such fibers were glued together to construct “+”-shaped hydrogels. After gluing, the hydrogels were embedded in Matrigel and cultured for several days. The cells spread and proliferated along the fibers, indicating that the electrochemical glue was not toxic toward the cells. This is the first report on the use of electrochemical glue for the assembly of hydrogel pieces containing cells. Based on our results, the electrochemical gluing method has promising applications in tissue engineering and the development of organs on a chip. Full article

(This article belongs to the Special Issue Frontiers in Micromachines in Japan)

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13 pages, 5635 KiB

Open AccessArticle

A Branched Polyelectrolyte Complex Enables Efficient Flame Retardant and Excellent Robustness for Wood/Polymer Composites

by Yanping Huang, Shuai Zhang, He Chen, Chunxiang Ding, Yan Xuan, Mingzhu Pan and Changtong Mei

Polymers 2020, 12(11), 2438; https://doi.org/10.3390/polym12112438 - 22 Oct 2020

Cited by 16 | Viewed by 3034

Abstract

Wood/thermoplastic composites (WPCs) have been restricted in some fields of building construction and electrical equipment because of their inherent high flammability and lower toughness. In this work, a branched crosslinking network polyelectrolyte complex (PEC) has been designed by incorporation of polyethyleneimine (PEI), a cation polyelectrolyte end capped amine groups, into cellulose nanocrystals (CNC), and ammonium polyphosphate (APP) via self-assembling. The hydrogen bonding interactions, penetration, and mechanical interlock provided by PEC effectively enhance the interfacial bonding within matrix, wood fibers, and flame retardant. Interestingly, it generates abundant micropores on the inner structure of WPC. The excellent interfacial bonding performance and easy-to-move molecular chain successfully transfer the stress and induce energy dissipation, simultaneously giving rise to higher strength and toughness for WPC. As well as the PEC endows WPC with a promotion in both smoke suppression and UL-94 V-0 rate. Additionally, the peak heat release rate and total smoke release for WPC obviously reduce by 36.9% and 50.0% respectively in presence of 25% PEC. A simple, eco-friendly, and concise strategy exhibits prospects for fiber-reinforced polymer composites with effective flame retardancy and mechanical robust properties. Full article

(This article belongs to the Collection Reinforced Polymer Composites)

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18 pages, 571 KiB

Open AccessArticle

A 3D Electroactive Polypyrrole-Collagen Fibrous Scaffold for Tissue Engineering

by Soh-Zeom Yow, Tze Han Lim, Evelyn K. F. Yim, Chwee Teck Lim and Kam W. Leong

Polymers 2011, 3(1), 527-544; https://doi.org/10.3390/polym3010527 - 28 Feb 2011

Cited by 60 | Viewed by 12204

Abstract

Fibers that can provide topographical, biochemical and electrical cues would be attractive for directing the differentiation of stem cells into electro-responsive cells such as neuronal or muscular cells. Here we report on the fabrication of polypyrrole-incorporated collagen-based fibers via interfacial polyelectrolyte complexation (IPC). The mean ultimate tensile strength of the fibers is 304.0 ± 61.0 MPa and the Young’s Modulus is 10.4 ± 4.3 GPa. Human bone marrow-derived mesenchymal stem cells (hMSCs) are cultured on the fibers in a proliferating medium and stimulated with an external electrical pulse generator for 5 and 10 days. The effects of polypyrrole in the fiber system can be observed, with hMSCs adopting a neuronal-like morphology at day 10, and through the upregulation of neural markers, such as noggin, MAP2, neurofilament, β tubulin III and nestin. This study demonstrates the potential of this fiber system as an attractive 3D scaffold for tissue engineering, where collagen is present on the fiber surface for cellular adhesion, and polypyrrole is encapsulated within the fiber for enhanced electrical communication in cell-substrate and cell-cell interactions. Full article

(This article belongs to the Special Issue Biofunctional Polymers for Medical Applications)

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