Effect of Sodium Alginate Concentration During Laser-Assisted Printing of Alginate Tubes

Author(s):  
Jingyuan Yan ◽  
Hemanth Gudapati ◽  
Yong Huang ◽  
Changxue Xu

For the free-form fabrication of various tissue constructs, three-dimensional (3D) additive printing technology has emerged as a promising approach for organ fabrication. This study aims to print a tube structure using a laser-assisted orifice-free printing technique and further investigate the effect of sodium alginate concentration on the tube wall thickness. Alginate tubes have been successfully printed. It is found that highly viscous materials can be laser printed into well-defined tube structures. A higher concentration solution such as the 8% sodium alginate solution leads to a thin wall, meaning a better resolution. Imaging analysis also illustrates that higher concentration solutions help develop smooth, slim jets upon the incidence of laser pulse.

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 679 ◽  
Author(s):  
Seyedmahmoud ◽  
Çelebi-Saltik ◽  
Barros ◽  
Nasiri ◽  
Banton ◽  
...  

Skeletal muscle tissue engineering aims to fabricate tissue constructs to replace or restore diseased or injured skeletal muscle tissues in the body. Several biomaterials and microscale technologies have been used in muscle tissue engineering. However, it is still challenging to mimic the function and structure of the native muscle tissues. Three-dimensional (3D) bioprinting is a powerful tool to mimic the hierarchical structure of native tissues. Here, 3D bioprinting was used to fabricate tissue constructs using gelatin methacryloyl (GelMA)-alginate bioinks. Mechanical and rheological properties of GelMA-alginate hydrogels were characterized. C2C12 myoblasts at the density 8 × 106 cells/mL were used as the cell model. The effects of alginate concentration (0, 6, and 8% (w/v)) and crosslinking mechanism (UV crosslinking or ionic crosslinking with UV crosslinking) on printability, cell viability, proliferation, and differentiation of bioinks were studied. The results showed that 10% (w/v) GelMA-8% (w/v) alginate crosslinked using UV light and 0.1 M CaCl2 provided the optimum niche to induce muscle tissue formation compared to other hydrogel compositions. Furthermore, metabolic activity of cells in GelMA bioinks was improved by addition of oxygen-generating particles to the bioinks. It is hoped that such bioprinted muscle tissues may find wide applications in drug screening and tissue regeneration.


2008 ◽  
Vol 400-402 ◽  
pp. 347-353
Author(s):  
Xiang Dong Xie ◽  
Li Hua Xu ◽  
Hao Ran Xu ◽  
Jian Min Zhou

With the rapid development of the subgrade or the foundation over recent years in China, there is a growing tendency for tall building to orient its directions to the more numbers of plies, much higher and more complex in plane layout. Moreover, some buildings adopt tube structure or bundled tube structure and so on to diversified development. The changing-rigidity of ground or foundation has obvious effects on superstructure when the buildings act on much higher and huge type. Therefore, in view of this, taking the bundled-tube structure of super high building for example in the paper, the method, equal the bundled tube structure of super high building and its foundation to stiffening-thin wall-combination, is adopted, then based on the three-dimensional model, the rigidity of subgrade and foundation’s effect on superstructure are given by calculation with semi-analysis. The calculated result indicated that there exist remarkable influence on sideway of the top end, the sideway between layers, the warp of the tube and the stresses between the subgrade and the bottom of the foundation.


Author(s):  
Deepika Saini ◽  
Sanoj Kumar ◽  
Manoj K. Singh ◽  
Musrrat Ali

AbstractThe key job here in the presented work is to investigate the performance of Generalized Ant Colony Optimizer (GACO) model in order to evolve the shape of three dimensional free-form Non Uniform Rational B-Spline (NURBS) curve using stereo (two) views. GACO model is a blend of two well known meta-heuristic optimization algorithms known as Simple Ant Colony and Global Ant Colony Optimization algorithms. Basically, the work talks about the solution of NURBS-fitting based reconstruction process. Therefore, GACO model is used to optimize the NURBS parameters (control points and weights) by minimizing the weighted least-square errors between the data points and the fitted NURBS curve. The algorithm is applied by first assuming some pre-fixed values of NURBS parameters. The experiments clearly show that the optimization procedure is a better option in a case where good initial locations of parameters are selected. A detailed experimental analysis is given in support of our algorithm. The implemented error analysis shows that the proposed methodology perform better as compared to the conventional methods.


Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 399
Author(s):  
Ambuj Srivastava ◽  
Dhanusha Yesudhas ◽  
Shandar Ahmad ◽  
M. Michael Gromiha

tRNA methyltransferase 5 (Trm5) enzyme is an S-adenosyl methionine (AdoMet)-dependent methyltransferase which methylates the G37 nucleotide at the N1 atom of the tRNA. The free form of Trm5 enzyme has three intrinsically disordered regions, which are highly flexible and lack stable three-dimensional structures. These regions gain ordered structures upon the complex formation with tRNA, also called disorder-to-order transition (DOT) regions. In this study, we performed molecular dynamics (MD) simulations of archaeal Trm5 in free and complex forms and observed that the DOT residues are highly flexible in free proteins and become stable in complex structures. The energetic contributions show that DOT residues are important for stabilising the complex. The DOT1 and DOT2 are mainly observed to be important for stabilising the complex, while DOT3 is present near the active site to coordinate the interactions between methyl-donating ligands and G37 nucleotides. In addition, mutational studies on the Trm5 complex showed that the wild type is more stable than the G37A tRNA mutant complex. The loss of productive interactions upon G37A mutation drives the AdoMet ligand away from the 37th nucleotide, and Arg145 in DOT3 plays a crucial role in stabilising the ligand, as well as the G37 nucleotide, in the wild-type complex. Further, the overall energetic contribution calculated using MMPBSA corroborates that the wild-type complex has a better affinity between Trm5 and tRNA. Overall, our study reveals that targeting DOT regions for binding could improve the inhibition of Trm5.


Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 794 ◽  
Author(s):  
Su Jeong Lee ◽  
Ji Min Seok ◽  
Jun Hee Lee ◽  
Jaejong Lee ◽  
Wan Doo Kim ◽  
...  

Bio-ink properties have been extensively studied for use in the three-dimensional (3D) bio-printing process for tissue engineering applications. In this study, we developed a method to synthesize bio-ink using hyaluronic acid (HA) and sodium alginate (SA) without employing the chemical crosslinking agents of HA to 30% (w/v). Furthermore, we evaluated the properties of the obtained bio-inks to gauge their suitability in bio-printing, primarily focusing on their viscosity, printability, and shrinkage properties. Furthermore, the bio-ink encapsulating the cells (NIH3T3 fibroblast cell line) was characterized using a live/dead assay and WST-1 to assess the biocompatibility. It was inferred from the results that the blended hydrogel was successfully printed for all groups with viscosities of 883 Pa∙s (HA, 0% w/v), 1211 Pa∙s (HA, 10% w/v), and 1525 Pa∙s, (HA, 30% w/v) at a 0.1 s−1 shear rate. Their structures exhibited no significant shrinkage after CaCl2 crosslinking and maintained their integrity during the culture periods. The relative proliferation rate of the encapsulated cells in the HA/SA blended bio-ink was 70% higher than the SA-only bio-ink after the fourth day. These results suggest that the 3D printable HA/SA hydrogel could be used as the bio-ink for tissue engineering applications.


AIP Advances ◽  
2015 ◽  
Vol 5 (8) ◽  
pp. 084901 ◽  
Author(s):  
Shangting You ◽  
Cuifang Kuang ◽  
Shuai Li ◽  
Xu Liu ◽  
Zhihua Ding

2010 ◽  
Vol 96 (2) ◽  
pp. 023114 ◽  
Author(s):  
B. D. F. Casse ◽  
W. T. Lu ◽  
Y. J. Huang ◽  
E. Gultepe ◽  
L. Menon ◽  
...  

2012 ◽  
Vol 166-169 ◽  
pp. 277-281
Author(s):  
Xiang Dong Xie ◽  
Xuan Wang ◽  
Li Qin

The superstructure and its foundation of a super tall building mega-frame structure are simplified equivalently and continuously to a stiffened-thin-wall tube on semi-infinite elastic subgrade. And the influences of static response on super tall building mega-frame structure caused by changes of frame rigidity are computed and analyzed with the three-dimensional model by semi-analytical approach based on ODE(Ordinary Differential Equation) Solver, considering the interactions of subgrade, foundation and superstructure. Then some valuable conclusions are obtained through analyzing the reasonable results of the numerical example.


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