A Brief Review of the Modelling of the Time Dependent Mechanical Properties of Tissue Engineering Scaffolds

2010 ◽  
Vol 6 ◽  
pp. 19-33 ◽  
Author(s):  
N.K. Bawolin ◽  
W.J. Zhang ◽  
Xiong Biao Chen
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Treatment Process ◽  
Effective Properties ◽  
Critical Role ◽  
Time Dependent ◽  
Tissue Engineering Scaffolds ◽  
Wide Range ◽  
Scaffold Degradation

The functionality of tissue scaffolds in vivo plays a critical role in the treatment process. Due to the time dependent nature of the mechanical properties of the constituent phases of the scaffold, a wide range of mechanical property histories may be observed during the treatment process, possibly influencing outcomes. The critical nature of the mechanical properties in load bearing applications indicates a need for the simultaneous modelling of both scaffold degradation and tissue regeneration with time, and the resulting effective properties of the tissue engineering construct. To this end, a review of the literature is conducted to identify the various existing approaches to modelling scaffold degradation, tissue behavior, and the dependency of the two processes on one another.

Modeling Material-Degradation-Induced Elastic Property of Tissue Engineering Scaffolds

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
N. K. Bawolin ◽  
M. G. Li ◽  
X. B. Chen ◽  
W. J. Zhang
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Molecular Weight ◽  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Element Model ◽  
Time Dependent ◽  
Tissue Engineering Scaffolds ◽  
The Finite Element Model

The mechanical properties of tissue engineering scaffolds play a critical role in the success of repairing damaged tissues/organs. Determining the mechanical properties has proven to be a challenging task as these properties are not constant but depend upon time as the scaffold degrades. In this study, the modeling of the time-dependent mechanical properties of a scaffold is performed based on the concept of finite element model updating. This modeling approach contains three steps: (1) development of a finite element model for the effective mechanical properties of the scaffold, (2) parametrizing the finite element model by selecting parameters associated with the scaffold microstructure and/or material properties, which vary with scaffold degradation, and (3) identifying selected parameters as functions of time based on measurements from the tests on the scaffold mechanical properties as they degrade. To validate the developed model, scaffolds were made from the biocompatible polymer polycaprolactone (PCL) mixed with hydroxylapatite (HA) nanoparticles and their mechanical properties were examined in terms of the Young modulus. Based on the bulk degradation exhibited by the PCL/HA scaffold, the molecular weight was selected for model updating. With the identified molecular weight, the finite element model developed was effective for predicting the time-dependent mechanical properties of PCL/HA scaffolds during degradation.

scholarly journals Investigation of the Effect of Agarose Gel Concentration and Culture Period on Bio and Mechanical Properties of Chondrocyte Tissue Engineering

2021 ◽  
Vol 22 (4) ◽  
pp. 767-774
Author(s):  
Akram Jawad
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Test Procedure ◽  
Mechanical Tests ◽  
Agarose Gel ◽  
Growth Environment ◽  
Wide Range ◽  
Curve Method

As a gel scaffold for chondrocyte tissue engineering, agarose concentration plays a significant role in the relationship between porosity and nutrition. In this work, the effect of concentration and period cultured on Glycosaminoglycan (GAG) and mechanical properties have been studied. A bovine chondrocytes have been isolated and seeded in different agarose gel scoffed concentrations, about 4% and 6%, for different period cultured, 0 and 7 days. The MTS machine and Spectrophotometric with calibration curve method were used to measure mechanical properties, and GAG concentration of the prepared samples, respectively. The results of mechanical tests and GAG contents shown that there are a wide range of dispersion in the most of the samples, which attribute to different factors. For mechanical properties, these factors could be attributed to anisotropic of the produced chondrocyte with agarose scaffolds, insufficient cells' dispersion within the gel scaffold during seeding and cultured time, and some test procedure condition, such as EBSS hydration. While for GAG results, those factors could be the differences of the cell growth environment between in-vitro and in vivo media. 

The Natural Flavonoid Naringenin Inhibits the Cell Growth of WilmsTumorinChildren by Suppressing TLR4/NF-κB Signaling

2020 ◽  
Vol 20 ◽  
Author(s):  
Hongtao Li ◽  
Peng Chen ◽  
Lei Chen ◽  
Xinning Wang
Keyword(s):  
Cell Growth ◽  
Western Blot ◽  
Wilms Tumor ◽  
Critical Role ◽  
Time Dependent ◽  
Luciferase Assay ◽  
Dependent Manner ◽  
Tlr4 Expression ◽  
Protein Levels

Background: Nuclear factor kappa B (NF-κB) is usually activated in Wilms tumor (WT) cells and plays a critical role in WT development. Objective: The study purpose was to screen a NF-κB inhibitor from natural product library and explore its effects on WT development. Methods: Luciferase assay was employed to assess the effects of natural chemical son NF-κB activity. CCK-8 assay was conducted to assess cell growth in response to naringenin. WT xenograft model was established to analyze the effect of naringenin in vivo. Quantitative real-time PCR and Western blot were performed to examine the mRNA and protein levels of relative genes, respectively. Results: Naringenin displayed significant inhibitory effect on NF-κB activation in SK-NEP-1 cells. In SK-NEP-1 and G-401 cells, naringenin inhibited p65 phosphorylation. Moreover, naringenin suppressed TNF-α-induced p65 phosphorylation in WT cells. Naringenin inhibited TLR4 expression at both mRNA and protein levels in WT cells. CCK-8 staining showed that naringenin inhibited cell growth of the two above WT cells in dose-and time-dependent manner, whereas Toll-like receptor 4 (TLR4) over expression partially reversed the above phenomena. Besides, naringenin suppressed WT tumor growth in dose-and time-dependent manner in vivo. Western blot found that naringenin inhibited TLR4 expression and p65 phosphorylation in WT xenograft tumors. Conclusion: Naringenin inhibits WT development viasuppressing TLR4/NF-κB signaling

Preparation, Characterization and In Vitro Release Kinetics of Vancomycin Carried β-TCP/Chitosan Composite Microspheres Used as Bone Tissue Engineering Scaffolds

2012 ◽  
Vol 512-515 ◽  
pp. 1821-1825
Author(s):  
Lin Zhang ◽  
Xue Min Cui ◽  
Qing Feng Zan ◽  
Li Min Dong ◽  
Chen Wang ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Release Kinetics ◽  
In Vitro Release ◽  
Cross Linking ◽  
Tissue Engineering Scaffolds ◽  
Composite Microspheres ◽  
Chitosan Composite ◽  
Vitro Release

A novel microsphere scaffolds composed of chitosan and β-TCP containing vancomycin was designed and prepared. The β-TCP/chitosan composite microspheres were prepared by solid-in-water-in-oil (s/w/o) emulsion cross-linking method with or without pre-cross-linking process. The mode of vancomycin maintaining in the β-TCP/chitosan composite microspheres was detected by Fourier transform infrared spectroscopy (FTIR). The in vitro release curve of vancomycin in simulated body fluid (SBF) was estimated. The results revealed that the pre-cross-linking prepared microspheres possessed higher loading efficiency (LE) and encapsulation efficiency (EE) especially decreasing the previous burst mass of vancomycin in incipient release. These composite microspheres got excellent sphere and well surface roughness in morphology. Vancomycin was encapsulated in composite microspheres through absorption and cross-linking. While in-vitro release curves illustrated that vancomycin release depond on diffusing firstly and then on the degradation ratio later. The microspheres loading with vancomycin would be to restore bone defect, meanwhile to inhibit bacterium proliferation. These bioactive, degradable composite microspheres have potential applications in 3D tissue engineering of bone and other tissues in vitro and in vivo.

scholarly journals Advanced Hydrogels for Cartilage Tissue Engineering: Recent Progress and Future Directions

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4199
Author(s):  
Mahshid Hafezi ◽  
Saied Nouri Khorasani ◽  
Mohadeseh Zare ◽  
Rasoul Esmaeely Neisiany ◽  
Pooya Davoodi
Keyword(s):  
Tissue Engineering ◽  
Cartilage Tissue Engineering ◽  
Cartilage Regeneration ◽  
Biomechanical Properties ◽  
Tissue Growth ◽  
Cartilage Tissue ◽  
Self Healing ◽  
Advantages And Disadvantages ◽  
Wide Range

Cartilage is a tension- and load-bearing tissue and has a limited capacity for intrinsic self-healing. While microfracture and arthroplasty are the conventional methods for cartilage repair, these methods are unable to completely heal the damaged tissue. The need to overcome the restrictions of these therapies for cartilage regeneration has expanded the field of cartilage tissue engineering (CTE), in which novel engineering and biological approaches are introduced to accelerate the development of new biomimetic cartilage to replace the injured tissue. Until now, a wide range of hydrogels and cell sources have been employed for CTE to either recapitulate microenvironmental cues during a new tissue growth or to compel the recovery of cartilaginous structures via manipulating biochemical and biomechanical properties of the original tissue. Towards modifying current cartilage treatments, advanced hydrogels have been designed and synthesized in recent years to improve network crosslinking and self-recovery of implanted scaffolds after damage in vivo. This review focused on the recent advances in CTE, especially self-healing hydrogels. The article firstly presents the cartilage tissue, its defects, and treatments. Subsequently, introduces CTE and summarizes the polymeric hydrogels and their advances. Furthermore, characterizations, the advantages, and disadvantages of advanced hydrogels such as multi-materials, IPNs, nanomaterials, and supramolecular are discussed. Afterward, the self-healing hydrogels in CTE, mechanisms, and the physical and chemical methods for the synthesis of such hydrogels for improving the reformation of CTE are introduced. The article then briefly describes the fabrication methods in CTE. Finally, this review presents a conclusion of prevalent challenges and future outlooks for self-healing hydrogels in CTE applications.

A novel biocompatible double network hydrogel consisting of konjac glucomannan with high mechanical strength and ability to be freely shaped

2015 ◽  
Vol 3 (9) ◽  
pp. 1769-1778 ◽  
Author(s):  
Zhiyong Li ◽  
Yunlan Su ◽  
Baoquan Xie ◽  
Xianggui Liu ◽  
Xia Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Cell Adhesion ◽  
Mechanical Strength ◽  
Synthetic Polymer ◽  
Natural Polymer ◽  
Tissue Engineering Scaffolds ◽  
Adhesion Properties ◽  
High Mechanical Strength ◽  
Double Network

A novel physically linked double-network (DN) hydrogel was prepared by natural polymer KGM and synthetic polymer PAAm. The DN hydrogels exhibit good mechanical properties, cell adhesion properties, and can be freely shaped, making such hydrogels promising for tissue engineering scaffolds.

scholarly journals Biomimicry in Bio-Manufacturing: Developments in Melt Electrospinning Writing Technology Towards Hybrid Biomanufacturing

2019 ◽  
Vol 9 (17) ◽  
pp. 3540 ◽  
Author(s):  
Ferdows Afghah ◽  
Caner Dikyol ◽  
Mine Altunbek ◽  
Bahattin Koc
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Cell Attachment ◽  
Three Dimensional ◽  
Future Perspective ◽  
Melt Electrospinning ◽  
Wide Range ◽  
Challenges And Opportunities ◽  
Potential Applications ◽  
Homogeneous Cell

Melt electrospinning writing has been emerged as a promising technique in the field of tissue engineering, with the capability of fabricating controllable and highly ordered complex three-dimensional geometries from a wide range of polymers. This three-dimensional (3D) printing method can be used to fabricate scaffolds biomimicking extracellular matrix of replaced tissue with the required mechanical properties. However, controlled and homogeneous cell attachment on melt electrospun fibers is a challenge. The combination of melt electrospinning writing with other tissue engineering approaches, called hybrid biomanufacturing, has introduced new perspectives and increased its potential applications in tissue engineering. In this review, principles and key parameters, challenges, and opportunities of melt electrospinning writing, and particularly, recent approaches and materials in this field are introduced. Subsequently, hybrid biomanufacturing strategies are presented for improved biological and mechanical properties of the manufactured porous structures. An overview of the possible hybrid setups and applications, future perspective of hybrid processes, guidelines, and opportunities in different areas of tissue/organ engineering are also highlighted.

scholarly journals A Critical Role of the p75 Tumor Necrosis Factor Receptor (p75TNF-R) in Organ Inflammation Independent of  TNF, Lymphotoxin α, or the p55TNF-R

1998 ◽  
Vol 188 (7) ◽  
pp. 1343-1352 ◽  
Author(s):  
Eleni Douni ◽  
George Kollias
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Critical Role ◽  
Tumor Necrosis Factor Receptor ◽  
Peripheral Blood Mononuclear ◽  
Enhanced Production ◽  
Wide Range ◽  
Lymphotoxin Α ◽  
Necrosis Factor

Despite overwhelming evidence that enhanced production of the p75 tumor necrosis factor receptor (p75TNF-R) accompanies development of specific human inflammatory pathologies such as multi-organ failure during sepsis, inflammatory liver disease, pancreatitis, respiratory distress syndrome, or AIDS, the function of this receptor remains poorly defined in vivo. We show here that at levels relevant to human disease, production of the human p75TNF-R in transgenic mice results in a severe inflammatory syndrome involving mainly the pancreas, liver, kidney, and lung, and characterized by constitutively increased NF-κB activity in the peripheral blood mononuclear cell compartment. This process is shown to evolve independently of the presence of TNF, lymphotoxin α, or the p55TNF-R, although coexpression of a human TNF transgene accelerated pathology. These results establish an independent role for enhanced p75TNF-R production in the pathogenesis of inflammatory disease and implicate the direct involvement of this receptor in a wide range of human inflammatory pathologies.

scholarly journals Feasibility of Spatially Offset Raman Spectroscopy for in Vitro and in Vivo Monitoring Mineralization of Bone Tissue Engineering Scaffolds

2016 ◽  
Vol 89 (1) ◽  
pp. 847-853 ◽  
Author(s):  
Zhiyu Liao ◽  
Faris Sinjab ◽  
Amy Nommeots-Nomm ◽  
Julian Jones ◽  
Laura Ruiz-Cantu ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Raman Spectroscopy ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Tissue Engineering Scaffolds ◽  
In Vivo Monitoring

Trajectory-Based Tissue Engineering for Cartilage Repair: Correlation Between Maturation Rate and Integration Capacity

2013 ◽  
Author(s):  
Matthew B. Fisher ◽  
Nicole Söegaard ◽  
David R. Steinberg ◽  
Robert L. Mauck
Keyword(s):  
Tissue Engineering ◽  
Time Course ◽  
Biomechanical Properties ◽  
Time Dependent ◽  
In Vivo Studies ◽  
Surgical Approaches ◽  
General Hypothesis ◽  
Vitro Assay

Given the limitations of current surgical approaches to treat articular cartilage injuries, tissue engineering (TE) approaches have been aggressively pursued over the past two decades. Although biochemical and biomechanical properties on the order of the native tissue have been achieved (1–5), several in-vitro and in-vivo studies indicate that increased tissue maturity may limit the ability of engineered constructs to remodel and integrate with surrounding cartilage, although results are highly variable (2, 6–8). Thus, “static” measures of construct maturity (e.g. compressive modulus) upon implantation may not be the best indicators of in-vivo success, which likely requires implanted TE constructs to mature, remodel, and integrate with the host over time to achieve optimal results. We recently introduced the concept of “trajectory-based” tissue engineering (TB-TE), which is based on the general hypothesis that time-dependent increases in construct maturation in-vitro prior to implantation (i.e. positive rates) may provide a better predictor of in-vivo success (9). As a first step in evaluating this concept, in the current study we hypothesized that time-dependent increases in equilibrium modulus (a metric of growth) would be correlated to ability of constructs to integrate to cartilage using an in-vitro assay. To test this hypothesis, the current objective was to determine and model the time course of maturation of TE constructs during in-vitro culture and to assess the ability of these constructs to integrate to cartilage at various points during their maturation.

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