scholarly journals Poly (Butylene Adipate-Co-Terephthalate) and Poly (Ɛ-Caprolactone) and Their Bionanocomposites with Cellulose Nanocrystals: Thermo-Mechanical Properties and Cell Viability Study

2019 ◽  
Vol 7 (3) ◽  
pp. 269-277
Author(s):  
Marcia Cristina Branciforti ◽  
Caroline Faria Bellani ◽  
Carolina Lipparelli Morelli ◽  
Alice Ferr ◽  
Nadia Benkirane-Jessel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Viability ◽  
Cellulose Nanocrystals ◽  
Viability Study

scholarly journals Mechanical properties and degradation studies of poly(mannitol sebacate)/cellulose nanocrystals nanocomposites

RSC Advances ◽  
2015 ◽  
Vol 5 (69) ◽  
pp. 55879-55891 ◽  
Author(s):  
Águeda Sonseca ◽  
Oscar Sahuquillo ◽  
E. Johan Foster ◽  
Enrique Giménez
Keyword(s):  
Mechanical Properties ◽  
Cellulose Nanocrystals ◽  
Sebacic Acid ◽  
Temperature Profiles ◽  
Degradation Studies

Two pre-polymers with ad-mannitol : sebacic acid 1 : 1 and 1 : 2 ratios respectively were combined with cellulose nanocrystals (CNCs) and crosslinked applying different time–temperature profiles to obtain PMS/CNC nanocomposites with different properties.

Effect of Freezing on Cell Viability and Mechanical Strength of Bioartificial Tissues

2001 ◽  
Author(s):  
Ramachandra V. Devireddy ◽  
Michael R. Neidert ◽  
John C. Bischof ◽  
Robert T. Tranquillo
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Cell Viability ◽  
Ultimate Tensile Stress ◽  
Collagen Gels ◽  
Cooling Rates ◽  
Human Foreskin Fibroblasts ◽  
Lower Strain ◽  
Maximum Stiffness ◽  
Eden Prairie

Abstract The effect of freezing on the viability and mechanical strength of bioartificial tissues was determined under a variety of cooling conditions, with the ultimate aim of optimizing the cryopreservation process. Bioartificial tissues (i.e. tissue-equivalents or TEs) were prepared by incubating entrapped human foreskin fibroblasts in collagen gels for a period of 2 weeks. The bioartificial tissues were frozen using a controlled rate freezer at various cooling rates (0.5, 2, 5, 20, 40 and > 1000°C/min or slam freezing). The viability (< 60 min after thawing) of the fibroblasts in the bioartificial tissue was assessed using the Ethidium Homodimer (dead cells stain red) and Hoechst Give cells stain blue) assay. Uniaxial tension experiments were performed on an MTS Microbionix System (Eden Prairie, MN) to assess the post-thaw mechanical properties (Maximum Stiffness; Ultimate Tensile Stress; and Strain to Failure) of the frozen-thawed bioartificial tissue (≤ 3 hours after thawing). The results suggest that cooling rates of either 2 or 5°C/min are optimal for preserving both the cell viability and mechanical properties of the bioartificial tissues, post-freeze. Bioartificial tissues were also frozen using a directional solidification stage at 5°C/min. The post-thaw viability results are comparable in both the directionally cooled and the controlled rate freezer samples. However, the mechanical properties of the directionally cooled samples are significantly different (with a higher maximum stiffness and a lower strain to failure) than those obtained for samples frozen using a controlled rate freezer. This suggests that the directionality of ice propagation into the sample affects the measured mechanical properties.

scholarly journals Three-Dimensional Stable Alginate-Nanocellulose Gels for Biomedical Applications: Towards Tunable Mechanical Properties and Cell Growing

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 78 ◽  
Author(s):  
Priscila Siqueira ◽  
Éder Siqueira ◽  
Ana Elza De Lima ◽  
Gilberto Siqueira ◽  
Ana Delia Pinzón-Garcia ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Tissue Engineering ◽  
Wound Healing ◽  
Cellulose Nanocrystals ◽  
Biomedical Applications ◽  
Cellulose Nanofibers ◽  
Oxidized Cellulose ◽  
Freeze Dried ◽  
Alginate Gels

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.

scholarly journals Effects of Encapsulated Cells on the Physical–Mechanical Properties and Microstructure of Gelatin Methacrylate Hydrogels

2019 ◽  
Vol 20 (20) ◽  
pp. 5061 ◽  
Author(s):  
Srikumar Krishnamoorthy ◽  
Behnam Noorani ◽  
Changxue Xu
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Cell Viability ◽  
Physical Properties ◽  
Pore Size ◽  
Cell Density ◽  
Tensile Modulus ◽  
Encapsulated Cells ◽  
3T3 Fibroblasts ◽  
Cell Densities

Gelatin methacrylate (GelMA) has been gaining popularity in recent years as a photo-crosslinkable biomaterial widely used in a variety of bioprinting and tissue engineering applications. Several studies have established the effects of process-based and material-based parameters on the physical–mechanical properties and microstructure of GelMA hydrogels. However, the effect of encapsulated cells on the physical–mechanical properties and microstructure of GelMA hydrogels has not been fully understood. In this study, 3T3 fibroblasts were encapsulated at different cell densities within the GelMA hydrogels and incubated over 96 h. The effects of encapsulated cells were investigated in terms of mechanical properties (tensile modulus and strength), physical properties (swelling and degradation), and microstructure (pore size). Cell viability was also evaluated to confirm that most cells were alive during the incubation. It was found that with an increase in cell density, the mechanical properties decreased, while the degradation and the pore size increased.

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