scholarly journals Helical nanofiber yarn enabling highly stretchable engineered microtissue

2019 ◽  
Vol 116 (19) ◽  
pp. 9245-9250 ◽  
Author(s):  
Yiwei Li ◽  
Fengyun Guo ◽  
Yukun Hao ◽  
Satish Kumar Gupta ◽  
Jiliang Hu ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Nuclear Translocation ◽  
Myogenic Differentiation ◽  
Helical Structure ◽  
Large Strains ◽  
Binding Motif ◽  
Nanofiber Yarn ◽  
High Viability ◽  
Highly Stretchable ◽  
Nonaffine Deformation

Development of microtissues that possess mechanical properties mimicking those of native stretchable tissues, such as muscle and tendon, is in high demand for tissue engineering and regenerative medicine. However, regardless of the significant advances in synthetic biomaterials, it remains challenging to fabricate living microtissue with high stretchability because application of large strains to microtissues can damage the cells by rupturing their structures. Inspired by the hierarchical helical structure of native fibrous tissues and its behavior of nonaffine deformation, we develop a highly stretchable and tough microtissue fiber made up of a hierarchical helix yarn scaffold, scaling from nanometers to millimeters, that can overcome this limitation. This microtissue can be stretched up to 15 times its initial length and has a toughness of 57 GJ m−3. More importantly, cells grown on this scaffold maintain high viability, even under severe cyclic strains (up to 600%) that can be attributed to the nonaffine deformation under large strains, mimicking native biopolymer scaffolds. Furthermore, as proof of principle, we demonstrate that the nanotopography of the helical nanofiber yarn is able to induce cytoskeletal alignment and nuclear elongation, which promote myogenic differentiation of mesenchymal stem cells by triggering nuclear translocation of transcriptional coactivator with PDZ-binding motif (TAZ). The highly stretchable microtissues we develop here will facilitate a variety of tissue engineering applications and the development of engineered living systems.

scholarly journals Long-Term Cryostorage of Mesenchymal Stem Cell-Containing Hybrid Hydrogel Scaffolds Based on Fibrin and Collagen

Gels ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 44
Author(s):  
Marfa N. Egorikhina ◽  
Yulia P. Rubtsova ◽  
Diana Ya. Aleynik
Keyword(s):  
Tissue Engineering ◽  
Proliferative Activity ◽  
Experimental Protocol ◽  
Hydrogel Scaffold ◽  
Hybrid Hydrogel ◽  
Hydrogel Scaffolds ◽  
High Viability ◽  
Scaffold Structure ◽  
Difficult Issue

The most difficult issue when using tissue engineering products is enabling the ability to store them without losing their restorative capacity. The numbers and viability of mesenchymal stem cells encapsulated in a hydrogel scaffold after cryostorage at −80 °C (by using, individually, two kinds of cryoprotectors—Bambanker and 10% DMSO (Dimethyl sulfoxide) solution) for 3, 6, 9, and 12 months were determined, with subsequent assessment of cell proliferation after 96 h. The analysis of the cellular component was performed using fluorescence microscopy and the two fluorochromes—Hoechst 3334 and NucGreenTM Dead 488. The experimental protocol ensured the preservation of cells in the scaffold structure, retaining both high viability and proliferative activity during storage for 3 months. Longer storage of scaffolds led to their significant changes. Therefore, after 6 months, the proliferative activity of cells decreased. Cryostorage of scaffolds for 9 months led to a decrease in cells’ viability and proliferative activity. As a result of cryostorage of scaffolds for 12 months, a decrease in viability and proliferative activity of cells was observed, as well as pronounced changes in the structure of the hydrogel. The described scaffold cryostorage protocol could become the basis for the development of storage protocols for such tissue engineering products, and for helping to extend the possibilities of their clinical use while accelerating their commercialization.

scholarly journals Calmodulin Directly Interacts with the Cx43 Carboxyl-Terminus and Cytoplasmic Loop Containing Three ODDD-Linked Mutants (M147T, R148Q, and T154A) that Retain α-Helical Structure, but Exhibit Loss-of-Function and Cellular Trafficking Defects

Biomolecules ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1452
Author(s):  
Li Zheng ◽  
Sylvie Chenavas ◽  
Fabien Kieken ◽  
Andrew Trease ◽  
Sarah Brownell ◽  
...  
Keyword(s):  
Helical Structure ◽  
Binding Motif ◽  
Loss Of Function ◽  
Dye Transfer ◽  
Cytoplasmic Loop ◽  
Calmodulin Binding ◽  
Downstream Effects ◽  
Junction Protein ◽  
Trafficking Defects

The autosomal-dominant pleiotropic disorder called oculodentodigital dysplasia (ODDD) is caused by mutations in the gap junction protein Cx43. Of the 73 mutations identified to date, over one-third are localized in the cytoplasmic loop (Cx43CL) domain. Here, we determined the mechanism by which three ODDD mutations (M147T, R148Q, and T154A), all of which localize within the predicted 1-5-10 calmodulin-binding motif of the Cx43CL, manifest the disease. Nuclear magnetic resonance (NMR) and circular dichroism revealed that the three ODDD mutations had little-to-no effect on the ability of the Cx43CL to form α-helical structure as well as bind calmodulin. Combination of microscopy and a dye-transfer assay uncovered these mutations increased the intracellular level of Cx43 and those that trafficked to the plasma membrane did not form functional channels. NMR also identify that CaM can directly interact with the Cx43CT domain. The Cx43CT residues involved in the CaM interaction overlap with tyrosines phosphorylated by Pyk2 and Src. In vitro and in cyto data provide evidence that the importance of the CaM interaction with the Cx43CT may lie in restricting Pyk2 and Src phosphorylation, and their subsequent downstream effects.

Soft network materials with isotropic negative Poisson's ratios over large strains

Soft Matter ◽  
2018 ◽  
Vol 14 (5) ◽  
pp. 693-703 ◽  
Author(s):  
Jianxing Liu ◽  
Yihui Zhang
Keyword(s):  
Tissue Engineering ◽  
Large Strains ◽  
Potential Applications ◽  
Poisson's Ratios ◽  
Poisson’S Ratios ◽  
Relative Constant

Soft network materials with isotropic and relative constant Poisson's ratios in the range from −1 to 1 over large strains are presented, with potential applications in tissue engineering and bioelectronics.

scholarly journals Nuclear import of isoforms of the cytomegalovirus kinase pUL97 is mediated by differential activity of NLS1 and NLS2 both acting through classical importin-α binding

2012 ◽  
Vol 93 (8) ◽  
pp. 1756-1768 ◽  
Author(s):  
Rike Webel ◽  
Sara M. Ø. Solbak ◽  
Christian Held ◽  
Jens Milbradt ◽  
Andrea Groß ◽  
...  
Keyword(s):  
Virus Replication ◽  
Nuclear Localization ◽  
Evaluation System ◽  
Nuclear Translocation ◽  
Helical Structure ◽  
Nucleocytoplasmic Transport ◽  
Resonance Spectroscopy ◽  
Translational Initiation ◽  
Importin Α ◽  
Arginine Residues

The multifunctional protein kinase pUL97 of human cytomegalovirus (HCMV) strongly determines the efficiency of virus replication. Previously, the existence of two pUL97 isoforms that arise from alternative translational initiation and show a predominant nuclear localization was described. Two bipartite nuclear localization sequences, NLS1 and NLS2, were identified in the N terminus of the large isoform, whilst the small isoform exclusively contained NLS2. The current study found the following: (i) pUL97 nuclear localization in HCMV-infected primary fibroblasts showed accumulations in virus replication centres and other nuclear sections; (ii) in a quantitative evaluation system for NLS activity, the large isoform showed higher efficiency of nuclear translocation than the small isoform; (iii) NLS1 was mapped to aa 6–35 and NLS2 to aa 190–213; (iv) using surface plasmon resonance spectroscopy, the binding of both NLS1 and NLS2 to human importin-α was demonstrated, stressing the importance of individual arginine residues in the bipartite consensus motifs; (v) nuclear magnetic resonance spectroscopy of pUL97 peptides confirmed an earlier statement about the functional requirement of NLS1 embedding into an intact α-helical structure; and (vi) a bioinformatics investigation of the solvent-accessible surface suggested a high accessibility of NLS1 and an isoform-specific, variable accessibility of NLS2 for interaction with importin-α. Thus, the nucleocytoplasmic transport mechanism of the isoforms appeared to be differentially regulated, and this may have consequences for isoform-dependent functions of pUL97 during virus replication.

scholarly journals Stretchable, Transparent, Ionic Conductors

Science ◽  
2013 ◽  
Vol 341 (6149) ◽  
pp. 984-987 ◽  
Author(s):  
Christoph Keplinger ◽  
Jeong-Yun Sun ◽  
Choon Chiang Foo ◽  
Philipp Rothemund ◽  
George M. Whitesides ◽  
...  
Keyword(s):  
Electrochemical Reaction ◽  
Transparent Conductors ◽  
Large Strains ◽  
Stretchable Electronics ◽  
Ionic Conductors ◽  
Sensors And Actuators ◽  
Electromechanical Transduction ◽  
Highly Stretchable ◽  
Electronic Conductors ◽  
Lower Sheet Resistance

Existing stretchable, transparent conductors are mostly electronic conductors. They limit the performance of interconnects, sensors, and actuators as components of stretchable electronics and soft machines. We describe a class of devices enabled by ionic conductors that are highly stretchable, fully transparent to light of all colors, and capable of operation at frequencies beyond 10 kilohertz and voltages above 10 kilovolts. We demonstrate a transparent actuator that can generate large strains and a transparent loudspeaker that produces sound over the entire audible range. The electromechanical transduction is achieved without electrochemical reaction. The ionic conductors have higher resistivity than many electronic conductors; however, when large stretchability and high transmittance are required, the ionic conductors have lower sheet resistance than all existing electronic conductors.

scholarly journals Preparation and Characterization of Sodium Alginate Polymeric Scaffold by Electrospinning Method for Skin Tissue Engineering Application

2021 ◽  
Author(s):  
Sorour Jadbabaei ◽  
Farid Naiemi ◽  
Hassan Ebadi-Dehaghani ◽  
Majid Kolahdoozan
Keyword(s):  
Tissue Engineering ◽  
Sodium Alginate ◽  
Engineering Application ◽  
L929 Cell ◽  
Skin Tissue ◽  
Tissue Engineering Application ◽  
Skin Tissue Engineering ◽  
Working Space ◽  
Polymeric Scaffold ◽  
High Viability

Abstract Sodium alginate (SA) approved its high potential in tissue engineering and regenerative medicine. One of the main weaknesses of this polysaccharide is its low spinnability which nanofiber based scaffolds are the interest of scientists in biomedical engineering. The main aim of this study was to improve the spinnability of SA in combination with polyvinyl alcohol (PVA). It was also tried to optimize the main parameters in electrospinning of the optimized SA;PVA ratio including voltage, flow rate, and working space. To aim this, Response surface methodology under central composite design was employed to design the experiments scientifically. The final nanofiber scaffolds were studied using scanning electron microscopy, Fourier transform infrared spectroscopy, degradability, swelling, tensile strength, porosity, nanofiber diameter, contact angle, and cytotoxicity. Based on the results, the best ratio for SA:PVA was 1:6.5. The solution with this concentration was spinnable in various values for the process parameters. The fabricated scaffolds under these conditions revealed good physical, chemical, mechanical, and biological features. L929 cell lines revealed high viability during 48 h of culture. The results revealed the uniform and homogeneous nanofibers with the regular size distribution (166 nm) were obtained at 30 kV, 0.55 µl/h, and 12.5 cm. To sum up, the optimized ratio under the reported conditions can be a good biologically compatible candidate for skin tissue engineering.

The Relevance of Large Strains in Functional Tissue Engineering of Heart Valves

2003 ◽  
Vol 51 (2) ◽  
pp. 78-83 ◽  
Author(s):  
A. Mol ◽  
C. V. C. Bouten ◽  
G. Zünd ◽  
C. I. Günter ◽  
J. F. Visjager ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Heart Valves ◽  
Large Strains ◽  
Functional Tissue Engineering ◽  
Functional Tissue

scholarly journals Myogenic differentiation of human amniotic mesenchymal cells and its tissue repair capacity on volumetric muscle loss

2019 ◽  
Vol 10 ◽  
pp. 204173141988710 ◽  
Author(s):  
Di Zhang ◽  
Kai Yan ◽  
Jing Zhou ◽  
Tianpeng Xu ◽  
Menglei Xu ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Tissue Engineering ◽  
Stem Cell ◽  
Tissue Repair ◽  
Myogenic Differentiation ◽  
Embryonic Stem ◽  
Mesenchymal Cells ◽  
Muscle Loss ◽  
Repair Capacity ◽  
Volumetric Muscle Loss

Stem cell–based tissue engineering therapy is the most promising method for treating volumetric muscle loss. Human amniotic mesenchymal cells possess characteristics similar to those of embryonic stem cells. In this study, we verified the stem cell characteristics of human amniotic mesenchymal cells by the flow cytometry analysis, and osteogenic and adipogenic differentiation. Through induction with the DNA demethylating agent 5-azacytidine, human amniotic mesenchymal cells can undergo myogenic differentiation and express skeletal muscle cell–specific markers such as desmin and MyoD. The Wnt/β-catenin signaling pathway also plays an important role. After 5-azacytidine-induced human amniotic mesenchymal cells were implanted into rat tibialis anterior muscle with volumetric muscle loss, we observed increased angiogenesis and improved local tissue repair. We believe that human amniotic mesenchymal cells can serve as a potential source of cells for skeletal muscle tissue engineering.

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