Analysis of the Dynamic Permeation Experiment with Implication to Cartilaginous Tissue Engineering

2004 ◽  
Vol 126 (4) ◽  
pp. 485-491 ◽  
Author(s):  
W. Y. Gu ◽  
D. N. Sun ◽  
W. M. Lai ◽  
V. C. Mow
Keyword(s):  
Tissue Engineering ◽  
Constitutive Model ◽  
Electrolyte Solution ◽  
Diffusion Coefficients ◽  
Electrical Potential ◽  
Fluid Pressure ◽  
Spatial Distributions ◽  
Cartilaginous Tissue ◽  
Fixed Charge Density ◽  
Ion Concentrations

In the present study, a 1-D dynamic permeation of a monovalent electrolyte solution through a negatively charged-hydrated cartilaginous tissue is analyzed using the mechano-electrochemical theory developed by Lai et al. (1991) as the constitutive model for the tissue. The spatial distributions of stress, strain, fluid pressure, ion concentrations, electrical potential, ion and fluid fluxes within and across the tissue have been calculated. The dependencies of these mechanical, electrical and physicochemical responses on the tissue fixed charge density, with specified modulus, permeability, diffusion coefficients, and frequency and magnitude of pressure differential are determined. The results demonstrate that these mechanical, electrical and physicochemical fields within the tissue are intrinsically and nonlinearly coupled, and they all vary with time and depth within the tissue.

SIPNs polymeric scaffold for use in cartilaginous tissue engineering: physical-chemical evaluation and biological behavior

2021 ◽  
Vol 26 ◽  
pp. 102111
Author(s):  
Elcio Malcher Dias Junior ◽  
Dayane dos Reis Costa Dias ◽  
Ana Paula Drummond Rodrigues ◽  
Carmen Gilda Barroso Tavares Dias ◽  
Gilmara de Nazareth Tavares Bastos ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Biological Behavior ◽  
Cartilaginous Tissue ◽  
Chemical Evaluation ◽  
Polymeric Scaffold ◽  
Physical Chemical

Measurement of spatial distributions of residual gas density and electrical potential in a plasma

1978 ◽  
Vol 18 (5) ◽  
pp. 617-621
Author(s):  
V. N. Bocharov ◽  
A. M. Kudryavtsev ◽  
A. F. Sorokin ◽  
Yu. N. Ul'yanov
Keyword(s):  
Electrical Potential ◽  
Spatial Distributions ◽  
Gas Density ◽  
Residual Gas

Electrophysiology of renal capillary membranes: gel concept applied and Starling model challenged

1988 ◽  
Vol 254 (3) ◽  
pp. F364-F373 ◽  
Author(s):  
M. Wolgast ◽  
G. Ojteg
Keyword(s):  
Charge Density ◽  
Electrical Potential ◽  
Potential Gradient ◽  
Swelling Pressure ◽  
Porous Membrane ◽  
Fixed Charge ◽  
Fixed Charge Density ◽  
Capillary Membranes ◽  
External Forces ◽  
Gel Membranes

In the classical Starling model the hydrostatic pressure in the pores is generally lower than that in capillary plasma, a phenomenon that necessitates the assumption of a rigid porous membrane. In flexible gel membranes, the capillary pressure is suggested to be balanced by a gel swelling pressure generated by negative fixed charges. Regarding the fluid transfer, the transmembranous electrical potential gradient will generate a net driving electroosmotic force. This force will be numerically similar to the net driving Starling force in small pores, but distinctly different in large pores. From previous data on the hydrostatic and colloid osmotic forces, the fixed charge density at the two interfaces of 1) the glomerular and 2) the peritubular capillary membrane were calculated and used to predict the flux of a series of charged protein probes. The close fit to the experimental data in both the capillary beds is in line with the gel concept presented. The gel concept (but hardly a rigid membrane) explains the ability of capillary membranes to alter their permeability in response to external forces. Gel membranes can furthermore be predicted to have a self-rinsing ability, as entrapped proteins will increase the local fixed charge density, leading to fluid entry into the region between the particle and the pore rim, which by consequent widening of the channel will facilitate extrusion of trapped proteins.

A Model for Bone Resorption

2006 ◽  
Author(s):  
Lars Johansson ◽  
Ulf Edlund ◽  
Anna Fahlgren ◽  
Per Aspenberg
Keyword(s):  
Fluid Flow ◽  
Bone Resorption ◽  
Constitutive Model ◽  
Bone Tissue ◽  
Driving Force ◽  
Strain State ◽  
Bone Remodelling ◽  
Fluid Pressure ◽  
Fluid Flow Velocity ◽  
Surgical Implants

In the present paper a model for the resorption of bone, such as that observed at the interface between surgical implants and bone tissue, is developed. While there are many previous studies where models for bone remodelling calculations are proposed, these have been based on the stress or strain state of the bone tissue itself as the driving force for bone remodelling. We, instead, develop a constitutive model based on observations in recent experiments where it seems that fluid pressure, or possibly fluid flow velocity, is a major factor in the bone resorption process.

scholarly journals Recent advances on gradient hydrogels in biomimetic cartilage tissue engineering

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 2158 ◽  
Author(s):  
Ivana Gadjanski
Keyword(s):  
Tissue Engineering ◽  
Articular Cartilage ◽  
Blood Vessels ◽  
Cartilage Tissue Engineering ◽  
Structure And Function ◽  
Cartilage Tissue ◽  
Cartilaginous Tissue ◽  
Zonal Structure ◽  
Promising Target ◽  
And Function

Articular cartilage (AC) is a seemingly simple tissue that has only one type of constituting cell and no blood vessels and nerves. In the early days of tissue engineering, cartilage appeared to be an easy and promising target for reconstruction and this was especially motivating because of widespread AC pathologies such as osteoarthritis and frequent sports-induced injuries. However, AC has proven to be anything but simple. Recreating the varying properties of its zonal structure is a challenge that has not yet been fully answered. This caused the shift in tissue engineering strategies toward bioinspired or biomimetic approaches that attempt to mimic and simulate as much as possible the structure and function of the native tissues. Hydrogels, particularly gradient hydrogels, have shown great potential as components of the biomimetic engineering of the cartilaginous tissue.

A Continuum Theory for Simulation of Ionic-Strength-Sensitive Hydrogel for BioMEMS Application

2009 ◽  
Vol 74 ◽  
pp. 21-24
Author(s):  
Fu Kun Lai ◽  
Hua Li
Keyword(s):  
Ionic Strength ◽  
Charge Density ◽  
Electrical Potential ◽  
Continuum Theory ◽  
Ionic Concentration ◽  
Fixed Charge ◽  
Buffer Solution ◽  
Fixed Charge Density ◽  
Flux System ◽  
Smart Hydrogel

A continuum multiphysics theory is presented for simulation of the ionic-strength-sensitive hydrogel and surrounding solution. The theory considers the coupled effects of chemical, electrical and mechanical multi-energy domains on the swelling behavior of the ionic-strength-sensitive hydrogel and is thus termed the multi-effect-coupling ionic-strength-stimuli (MECis) model. The MECis model consists of several governing equations, including Nernst-Planck flux system, Poisson equation, fixed charge density and mechanical equilibrium equation, in which the effect of the ionic strength is incorporated into the governing equation of diffusive flux and fixed charge. The theory is capable of simulating the swelling/shrinking behavior of smart hydrogel in buffer solution subject to the change in the ionic strength, and providing the distribution of the ionic concentration and electrical potential for applications of BioMEMS design. Apart from the ionic strength as the main stimulus, the influence of several parameters is discussed in detail, including the initial fixed charge density and Young’s modulus of the hydrogel.

Mechano-Active Cartilage Tissue Engineering

2006 ◽  
Vol 49 ◽  
pp. 189-196
Author(s):  
Soo Hyun Kim ◽  
Young Mee Jung ◽  
Sang Heon Kim ◽  
Young Ha Kim ◽  
Jun Xie ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Dynamic Compression ◽  
Cartilage Tissue Engineering ◽  
Compressive Deformation ◽  
Cartilage Tissue ◽  
Cartilaginous Tissue ◽  
Pressing Method ◽  
Safranin O

To engineer cartilaginous constructs with a mechano-active scaffold and dynamic compression was performed for effective cartilage tissue engineering. Mechano-active scaffolds were fabricated from very elastic poly(L-lactide-co-ε-carprolactone)(5:5). The scaffolds with 85 % porosity and 300~500 μm pore size were prepared by a gel-pressing method. The scaffolds were seeded with chondrocytes and the continuous compressive deformation of 5% strain was applied to cell-polymer constructs with 0.1Hz to evaluate for the effect of dynamic compression for regeneration of cartilage. Also, the chondrocytes-seeded constructs stimulated by the continuous compressive deformation of 5% strain with 0.1Hz for 10 days and 24 days respectively were implanted in nude mice subcutaneously to investigate their biocompatibility and cartilage formation. From biochemical analyses, chondrogenic differentiation was sustained and enhanced significantly and chondrial extracellular matrix was increased through mechanical stimulation. Histological analysis showed that implants stimulated mechanically formed mature and well-developed cartilaginous tissue, as evidenced by chondrocytes within lacunae. Masson’s trichrome and Safranin O staining indicated an abundant accumulation of collagens and GAGs. Also, ECM in constructs was strongly immuno-stained with anti-rabbit collagen type II antibody. Consequently, the periodic application of dynamic compression can improve the quality of cartilaginous tissue formed in vitro and in vivo.

Extended “LMPHETS” Finite Element Models for Coupled Mechano-Electro-Chemical Transport in Soft Tissues

2002 ◽  
Author(s):  
B. R. Simon ◽  
G. A. Radtke ◽  
P. H. Rigby ◽  
S. K. Williams ◽  
Z. P. Liu
Keyword(s):  
Finite Element ◽  
Soft Tissues ◽  
Electrical Potential ◽  
Fluid Pressure ◽  
Nonlinear Material ◽  
Solid Matrix ◽  
Test Problems ◽  
Finite Element Models ◽  
Material Interfaces ◽  
Mobile Species

Soft tissues are hydrated fibrous materials that exhibit nonlinear material response and undergo finite straining during in vivo loading. A continuum model of these structures (“LMPHETS” [1,2]) is a porous solid matrix (with charges fixed to the solid fibers) saturated by a mobile fluid (water) and multiple species (e.g., three mobile species designated by α, β = p, m, b where p = +, m = −, and b = ± charge) dissolved in the mobile fluid. A “mixed” LMPHETS theory and finite element models (FEMs) were presented [1] in which the “primary fields” are the displacements, ui = xi − Xi and the mechano-electro-chemical potentials, ν˜ξ* (ξ, η = f, e, m, b) that are continuous across material interfaces. “Secondary fields” (discontinuous at material boundaries) are mechanical fluid pressure, pf; electrical potential, μ˜e; and concentration or “molarity”, cα = dnα / dVf. Here an extended version of these models is described and numerical results are presented for representative test problems associated with transport in soft tissues.

A Model to Determine the Location of Heavy Metal Contaminant Source

2012 ◽  
Vol 610-613 ◽  
pp. 1023-1027 ◽  
Author(s):  
Zhi Jia Wang ◽  
Hu Wang ◽  
Hai Lang Gao ◽  
Peiai Zhang
Keyword(s):  
Heavy Metal ◽  
Diffusion Coefficients ◽  
High Accuracy ◽  
Spatial Distributions ◽  
Absorption Coefficients ◽  
Contaminant Source ◽  
Transmission Modes ◽  
Contaminant Sources ◽  
Metal Contaminant ◽  
Human Brains

We conducted a tracing model which was based on the process of dopamine diffusion in human brains, taking the diffusion coefficients and absorption coefficients into consideration. By combining with the spatial distributions of heavy metals plotted by ArcGIS, we can determine the contaminant sources and the results have high accuracy. Besides, we made an improvement in consideration of different transmission modes of heavy metal contaminants and the corresponding dilution factors.

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