scholarly journals Three-dimensional Hydrogels of Alginate/chitosan Semi-interpenetrating Polymer Networks and Nanocelluloses

Author(s):  
Priscila Siqueira ◽  
Ana de Lima ◽  
Felipe Medeiros ◽  
Augusta Isaac ◽  
Katia Novack ◽  
...  

Abstract The hydrogels are advanced materials used in biomedical applications during wound healing, controlled drug release and to prepare scaffolds. In this work are prepared hydrogels of alginate/chitosan (Alg/Ch) semi-interpenetrating polymer networks (semi-IPN’s) and nanocelluloses. The hydrogels after preparation by freeze drying are namely simply as gels. The cellulose nanocrystals (CNC’s) are obtained from acid hydrolysis of bleached Eucalyptus pulps and oxidized cellulose nanocrystals (CNCT’s) prepared by (2,2,6,6-tetramethylpiperidin-1-yl)oxyl radical catalyzed reaction as known as TEMPO reaction. The cellulose nanofibers (NFC’s) are obtained from mechanical shearing of cellulose pulps and oxidized NFC’s by TEMPO-mediated reaction (NFCT’s). The nanocellulose suspension and gels are characterized by FTIR at ATR mode, TGA, XRD, TEM, SEM, X-ray computed microtomography (micro-CT) and DMTA. The addition of CNC’s, NFC’s, CNCT’s or NFCT’s in the microstructure of gels increases their dimensional stabilities. The best results are obtained when CNCT’s and NFCT’s are added. The mechanical properties and dimensional stability of Alg/Ch semi-IPN’s increase after controlled thermal post-treatment. The heating during thermal post-treatment boosts the physicochemical interactions in the microstructures of semi-IPN’s. The biological assays show biocompatibility of fibroblast cells on the substrates, and differentiation and proliferation up seven days. The optimized mechanical properties, dimensional stability and biocompatibility of the gels studied in this work are important parameters for potential biomedical applications of these biomaterials.

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 78 ◽  
Author(s):  
Priscila Siqueira ◽  
Éder Siqueira ◽  
Ana Elza De Lima ◽  
Gilberto Siqueira ◽  
Ana Delia Pinzón-Garcia ◽  
...  

Hydrogels have been studied as promising materials in different biomedical applications such as cell culture in tissue engineering or in wound healing. In this work, we synthesized different nanocellulose-alginate hydrogels containing cellulose nanocrystals, TEMPO-oxidized cellulose nanocrystals (CNCTs), cellulose nanofibers or TEMPO-oxidized cellulose nanofibers (CNFTs). The hydrogels were freeze-dried and named as gels. The nanocelluloses and the gels were characterized by different techniques such as Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMTA), while the biological features were characterized by cytotoxicity and cell growth assays. The addition of CNCTs or CNFTs in alginate gels contributed to the formation of porous structure (diameter of pores in the range between 40 and 150 μm). TEMPO-oxidized cellulose nanofibers have proven to play a crucial role in improving the dimensional stability of the samples when compared to the pure alginate gels, mainly after a thermal post-treatment of these gels containing 50 wt % of CNFT, which significantly increased the Ca2+ crosslinking density in the gel structure. The morphological characteristics, the mechanical properties, and the non-cytotoxic behavior of the CNFT-alginate gels improved bioadhesion, growth, and proliferation of the cells onto the gels. Thus, the alginate-nanocellulose gels might find applications in tissue engineering field, as for instance, in tissue repair or wound healing applications.


2020 ◽  
Vol 28 ◽  
Author(s):  
Qi Yuan ◽  
Jing Bian ◽  
Ming-Guo Ma

Background: Recently, there has been increasing interest in nanomaterials processed using renewable and sustainable resources. Nanocellulose-based materials are of paramount value in the applications of biomedicine owing to their tailorable surface modification, favorable optical transparency, good hydrophilicity, excellent biocompatibility, and outstanding mechanical properties. Methods: In the review, the recent advancements of nanocellulose, including cellulose nanofibers (CNFs), cellulose nanocrystals (CNCs), and bacterial cellulose (BC), are summarized, which are promising for biomedical applications. Results: By discussing different forms (one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D)), the superiority of the nanocellulose-based materials with different constructed structures will be clarified for various biomedical applications, such as biosensing, drug delivery, wound dressing, and tissue engineering. Conclusion: Furthermore, the challenges and prospects for future development of nanocellulose-based materials in biomedical applications are also discussed at the end in the review.


2004 ◽  
Vol 370 (1-2) ◽  
pp. 288-292 ◽  
Author(s):  
A Bartolotta ◽  
G Di Marco ◽  
M Lanza ◽  
G Carini ◽  
G D’Angelo ◽  
...  

2005 ◽  
Vol 475-479 ◽  
pp. 1001-1004
Author(s):  
Ninglin Zhou ◽  
Xiao Xian Xia ◽  
Li Li ◽  
Shao Hua Wei ◽  
Jian Shen

A novel exfoliated polyurethane (PU)/clay Interpenetrating Polymer Networks (IPNs) nanocomposite has been synthesized with polyurethane and organoclay. MTPAC is used as swelling agent to treat Na-montmorillonite for forming organoclay. The results indicate that there is very good compatibility between organoclay and PU. Nanoscale silicate dispersion was analyzed by XRD. The mechanical properties of the nanocomposites have been measured by tensile testing machine. The nanocomposites show obviously improved physical and mechanical properties when compared with the pure polymer. Additionally, PU /MTPAC- clay shows lower water absorption properties than pure PU do. In addition, the reinforcing and intercalating mechanism of silicate layers in polyurethane matrix are discussed.


2012 ◽  
Vol 627 ◽  
pp. 873-877
Author(s):  
Xiao Xia Jian ◽  
Le Qin Xiao ◽  
Wei Liang Zhou ◽  
Hai Qin Ding

The Semi-Interpenetrating Polymer Networks(Semi-IPNs) of poly(methyl methyacrylate/ethyl acrylate)(P(MMA/EA)) and polyurethane thermoplastic elastomer (PU) were synthesized by PU and copolymer of methyl methacrylate and ethyl acrylate to improve the compatibility of polymethyl methacrylate(PMMA) and PU Semi-IPNs . The structure and properties were investigated by Fourier transform infrared spectrometer, Solid nuclear magnetic resonance spectrometry, Dynamic mechanical thermal analysis and Mechanical properties. The tensile stress of (P(MMA/EA)/PU)( P(MMA/EA):PU=3:7) can get to 9.6MPa, the additional physical crosslinks and entanglement for Semi-IPNs are the reasons.


2005 ◽  
Vol 873 ◽  
Author(s):  
Masanobu Naito ◽  
Takashi Nakai ◽  
Takuma Kawabe ◽  
Kenji Mori ◽  
Daisuke Furuta ◽  
...  

AbstractEnvironmentally friendly organic-inorganic hybrid materials with repellent activity against marine fouling organisms have been developed using interpenetrating polymer networks (IPNs), composed of a three-dimensional silica matrix of tetraethoxysilane (TEOS) and chain-like polymers, such as poly(methylmethacrylate) (PMMA) and poly(vinylacetate) (PVAc). The repellent activity of the IPNs reached a maximum of approximately 90% relative to that of tetrabutyl tin oxide (TBTO). Simple bioassays using blue mussels and algae were used to screen out the adequate proportions of those components.


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