Macro- and Micro-Scale Probing of the Mechanical Properties of DNA-Crosslinked Gels Using Embedded Inclusions

2005 ◽  
Vol 897 ◽  
Author(s):  
David C. Lin ◽  
Bernard Yurke ◽  
David I. Shreiber ◽  
Uday Chippada ◽  
Xue Jiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnetic Beads ◽  
Cell Attachment ◽  
Shape Change ◽  
Large Diameter ◽  
Tissue Engineering Scaffolds ◽  
Shear Moduli ◽  
Self Assembling ◽  
Subject Material ◽  
External Stimuli

AbstractMechanical properties of a class of self-assembling hydrogels based on DNA hybridization were studied using rigid, embedded inclusions. Because inclusions can be deflected without direct contact with a manipulator (e.g., magnet) once they are embedded within the subject material, the measurement technique is well suited for monitoring instantaneous and time-varying changes in the mechanical properties of active materials as they respond to external stimuli. In gels crosslinked with complementary strands of oligonucleotides, hybridization chemistry and strand displacement mechanisms allow reversible assembly, shape change, and large changes in compliance through the application of particular strands of DNA. In earlier work using large (diameter ∼0.8 mm) magnetic beads, the scaling behavior of the global elastic modulus with crosslink density was determined. More recently, it was shown that a threefold increase in stiffness was possible by generating prestress in the DNA-crosslinked gel network. Currently, the gels are functionalized to support cell attachment and embedded with micro-fabricated nickel bars. Through the measurement of local elastic and shear moduli as well as Poisson’s ratios, cell-substrate interactions can be used as a means of evaluating the potential of DNA-crosslinked gels as active cellular engineering substrates and tissue engineering scaffolds.

scholarly journals Design of RGDS Peptide-Immobilized Self-Assembling β-Strand Peptide from Barnacle Protein

2021 ◽  
Vol 22 (3) ◽  
pp. 1240
Author(s):  
Daisuke Fujii ◽  
Kento Takase ◽  
Ami Takagi ◽  
Kei Kamino ◽  
Yoshiaki Hirano
Keyword(s):  
Cell Adhesion ◽  
Cell Attachment ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Tissue Engineering Scaffolds ◽  
Self Assembling ◽  
Polystyrene Plate ◽  
Coated Cell ◽  
Ft Ir ◽  
Adhesive Proteins

We designed three types of RGD-containing barnacle adhesive proteins using self-assembling peptides. In the present study, three types of RGD-containing peptides were synthesized by solid-phase peptide synthesis, and the secondary structures of these peptides were analyzed by CD and FT-IR spectroscopy. The mechanical properties of peptide hydrogels were characterized by a rheometer. We discuss the correlation between the peptide conformation, and cell attachment and cell spreading activity from the viewpoint of developing effective tissue engineering scaffolds. We created a peptide-coated cell culture substrate by coating peptides on a polystyrene plate. They significantly facilitated cell adhesion and spreading compared to a non-coated substrate. When the RGDS sequence was modified at N- or C-terminal of R-Y, it was found that the self-assembling ability was dependent on the strongly affects hydrogel formation and cell adhesion caused by its secondary structure.

scholarly journals Fabrication and Characterization of Electrospun Polycaprolactone Blended with Chitosan-Gelatin Complex Nanofibrous Mats

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yongfang Qian ◽  
Zhen Zhang ◽  
Laijiu Zheng ◽  
Ruoyuan Song ◽  
Yuping Zhao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Weight Ratio ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Tissue Engineering Scaffolds ◽  
Elongation At Break ◽  
Nanofibrous Scaffolds ◽  
Two Peaks

Design and fabrication of nanofibrous scaffolds should mimic the native extracellular matrix. This study is aimed at investigating electrospinning of polycaprolactone (PCL) blended with chitosan-gelatin complex. The morphologies were observed from scanning electron microscope. As-spun blended mats had thinner fibers than pure PCL. X-ray diffraction was used to analyze the degree of crystallinity. The intensity at two peaks at 2θof 21° and 23.5° gradually decreased with the percentage of chitosan-gelatin complex increasing. Moreover, incorporation of the complex could obviously improve the hydrophilicity of as-spun blended mats. Mechanical properties of as-spun nanofibrous mats were also tested. The elongation at break of fibrous mats increased with the PCL content increasing and the ultimate tensile strength varied with different weight ratios. The as-spun mats had higher tensile strength when the weight ratio of PCL to CS-Gel was 75/25 compared to pure PCL. Both as-spun PCL scaffolds and PCL/CS-Gel scaffolds supported the proliferation of porcine iliac endothelial cells, and PCL/CS-Gel had better cell viability than pure PCL. Therefore, electrospun PCL/Chitosan-gelatin nanofibrous mats with weight ratio of 75/25 have better hydrophilicity mechanical properties, and cell proliferation and thus would be a promising candidate for tissue engineering scaffolds.

Quantitative Studies of Fibronectin Adsorption on Submicron Scaffolds

2012 ◽  
Author(s):  
Shawn Regis ◽  
Manisha Jassal ◽  
Sina Youssefian ◽  
Nima Rahbar ◽  
Sankha Bhowmick
Keyword(s):  
Surface Functionalization ◽  
Cultured Cells ◽  
Cell Attachment ◽  
Md Simulations ◽  
Cell Types ◽  
Biological Processes ◽  
Integrin Receptors ◽  
Tissue Engineering Scaffolds ◽  
Quantitative Studies

Fibronectin plays a crucial role in adhesion of several cell types, mainly due to the fact that it is recognized by at least ten different integrin receptors. Since most cell types can bind to fibronectin, it becomes involved in many various biological processes. The interaction of cells with ECM proteins such as fibronectin provides the signals affecting morphology, motility, gene expression, and survival of cells [1]. Fibronectin exists in both soluble and insoluble forms; soluble fibronectin is secreted by cells and exits in cell media or body fluids, whereas insoluble fibronectin exists in tissues or the extracellular matrix of cultured cells [2]. The ability to control adsorption of fibronectin on tissue engineering scaffolds would therefore play a huge role in controlling cell attachment and survival in vivo. This can be achieved through surface functionalization of the scaffolds. The goal of these studies is to use molecular dynamics (MD) simulations to mechanistically understand how fibronectin adsorption is enhanced by surface functionalization of submicron scaffolds.

A self-assembling amphiphilic perylene bisimide and its application for WORM memory devices

2016 ◽  
Vol 40 (10) ◽  
pp. 8886-8891 ◽  
Author(s):  
Junfeng Li ◽  
Chenglong Yang ◽  
Ying Chen ◽  
Wen-Yong Lai
Keyword(s):  
Memory Device ◽  
Memory Devices ◽  
Perylene Bisimide ◽  
Self Assembling ◽  
External Stimuli

Morphologies of the amphiphilic perylene bisimide assemblies were controlled and switched by external stimuli to afford a good-performance WORM memory device.

scholarly journals Drug-Loaded Biomimetic Ceramics for Tissue Engineering

Pharmaceutics ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 272 ◽  
Author(s):  
Patricia Diaz-Rodriguez ◽  
Mirian Sánchez ◽  
Mariana Landin
Keyword(s):  
Tissue Engineering ◽  
Cell Attachment ◽  
Release Kinetics ◽  
Drug Loading ◽  
Critical Parameters ◽  
Tissue Engineering Scaffolds ◽  
Biomimetic Scaffolds ◽  
Proliferation And Differentiation ◽  
Therapeutic Molecules ◽  
Biological Performance

The mimesis of biological systems has been demonstrated to be an adequate approach to obtain tissue engineering scaffolds able to promote cell attachment, proliferation, and differentiation abilities similar to those of autologous tissues. Bioceramics are commonly used for this purpose due to their similarities to the mineral component of hard tissues as bone. Furthermore, biomimetic scaffolds are frequently loaded with diverse therapeutic molecules to enhance their biological performance, leading to final products with advanced functionalities. In this review, we aim to describe the already developed bioceramic-based biomimetic systems for drug loading and local controlled release. We will discuss the mechanisms used for the inclusion of therapeutic molecules on the designed systems, paying special attention to the identification of critical parameters that modulate drug loading and release kinetics on these scaffolds.

Interfacial stability and shape change of anisotropic endoskeleton droplets

Soft Matter ◽  
2014 ◽  
Vol 10 (38) ◽  
pp. 7647-7652 ◽  
Author(s):  
Marco Caggioni ◽  
Alexandra V. Bayles ◽  
Jessica Lenis ◽  
Eric M. Furst ◽  
Patrick T. Spicer
Keyword(s):  
Yield Stress ◽  
Shape Change ◽  
Laplace Pressure ◽  
Interfacial Stability ◽  
External Stimuli

Stable anisotropic droplet shapes are created by balancing interfacial Laplace pressure with droplet yield stress. The endoskeleton droplets can be made to collapse controllably using external stimuli, like dilution, to enhance deposition on surfaces.

Effect of Expansion Ratio and Wall Thickness on Large-Diameter Solid Expandable Tubular after Expansion

2021 ◽  
Author(s):  
Changshuai Shi ◽  
Kailin Chen ◽  
Xiaohua Zhu ◽  
Feilong Cheng ◽  
Yuekui Qi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Internal Pressure ◽  
Wall Thickness ◽  
Performance Test ◽  
Large Diameter ◽  
Expansion Ratio ◽  
Fe Model ◽  
Laboratory Test Results ◽  
Low Efficiency ◽  
Pressure Resistance

Abstract The large-diameter solid expandable tubular with a smaller wall thickness faces the risk of internal pressure burst and external squeeze collapse in repairing damaged casing well. The internal pressure and external squeezing resistance calculation of the tubes using the analytical method require many expansion experiments and post-expansion tensile experiments, resulting in high costs and low efficiency. This paper gives a set of laboratory expansion and post-expansion performance test, which is based on the laboratory experiment and mechanical properties of material expansion. Two materials are studied: 316L and 20G. Then it analyses the error and causes of the error in the traditional analytical algorithm. Besides, it establishes an accurate finite element (FE) model to study the quantitative influence of expansion ratio and wall thickness on the burst strengths and collapse strengths of the tube. The results show that the toughness and hardening ratio of 316L is better than 20G at the same expansion ratio. The numerical simulation results of the model can effectively simulate the expansion process and the mechanical properties of SET in good agreement with the laboratory test results. The expansion ratio and wall thickness affect the mechanical properties after expansion. Thus the quantitative laws of the expansion driving force, internal pressure resistance, and external squeezing resistance under different variables are summarized. To ensure the integrity of the reinforced wellbore, the expansion ratio should not exceed 12.7%. In the current study lays a theoretical basis and technical support for optimizing SET and preventing downhole accidents.

The mechanics of single cross-links which mediate cell attachment at a hydrogel surface

Nanoscale ◽  
2019 ◽  
Vol 11 (24) ◽  
pp. 11596-11604 ◽  
Author(s):  
Arzu Çolak ◽  
Bin Li ◽  
Johanna Blass ◽  
Kaloian Koynov ◽  
Aranzazu del Campo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Adhesion ◽  
Cell Attachment ◽  
Force Spectroscopy ◽  
Single Cross ◽  
Mediate Cell Adhesion ◽  
Cross Links ◽  
Hydrogel Surface ◽  
Mediate Cell

The mechanical properties of single cross-links which mediate cell adhesion are explored by force spectroscopy.

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