The influence of different geometries of matrix/scaffold on the remodeling process of a bone and bioresorbable material mixture with voids

2015 ◽  
Vol 22 (5) ◽  
pp. 969-987 ◽  
Author(s):  
Ivan Giorgio ◽  
Ugo Andreaus ◽  
Tomasz Lekszycki ◽  
Alessandro Della Corte
Keyword(s):  
Bone Growth ◽  
Matrix Material ◽  
Porous Solids ◽  
Artificial Material ◽  
Matrix Deposition ◽  
Aspect Ratios ◽  
Adopted Model ◽  
The Matrix ◽  
Bioresorbable Material

Since internal architecture greatly influences crucial factors for tissue regeneration, such as nutrient diffusion, cell adhesion and matrix deposition, scaffolds have to be carefully designed, keeping in mind case-specific mechanical, mass transport and biological requirements. However, customizing scaffold architecture to better suit conflicting requirements, such as biological and mechanical ones, remains a challenging issue. Recent advances in printing technologies, together with the synthesis of novel composite biomaterials, have enabled the fabrication of various scaffolds with defined shape and controlled in vitro behavior. Thus, the influence of different geometries of the assemblage of the matrix and scaffold on the remodeling processes of living bone and artificial material should be investigated. To this end, two implant shapes are considered in this paper, namely a circular inclusion and a rectangular groove of different aspect ratios. A model of a mixture of bone tissue and bioresorbable material with voids was used to numerically analyze the physiological balance between the processes of bone growth and resorption and artificial material resorption in a plate-like sample. The adopted model was derived from a theory for the behavior of porous solids in which the matrix material is elastic and the interstices are void of material.

scholarly journals Dynamic Compression Promotes the Matrix Synthesis of Nucleus Pulposus Cells Through Up-Regulating N-CDH Expression in a Perfusion Bioreactor Culture

2018 ◽  
Vol 46 (2) ◽  
pp. 482-491 ◽  
Author(s):  
Yichun Xu ◽  
Hui Yao ◽  
Pei Li ◽  
Wenbin Xu ◽  
Junbin Zhang ◽  
...  
Keyword(s):  
Nucleus Pulposus ◽  
Dynamic Compression ◽  
Akt Pathway ◽  
Bioreactor Culture ◽  
Nucleus Pulposus Cells ◽  
Matrix Synthesis ◽  
Static Compression ◽  
Matrix Deposition ◽  
The Matrix

Background/Aims: An adequate matrix production of nucleus pulposus (NP) cells is an important tissue engineering-based strategy to regenerate degenerative discs. Here, we mainly aimed to investigate the effects and mechanism of mechanical compression (i.e., static compression vs. dynamic compression) on the matrix synthesis of three-dimensional (3D) cultured NP cells in vitro. Methods: Rat NP cells seeded on small intestinal submucosa (SIS) cryogel scaffolds were cultured in the chambers of a self-developed, mechanically active bioreactor for 10 days. Meanwhile, the NP cells were subjected to compression (static compression or dynamic compression at a 10% scaffold deformation) for 6 hours once per day. Unloaded NP cells were used as controls. The cellular phenotype and matrix biosynthesis of NP cells were investigated by real-time PCR and Western blotting assays. Lentivirus-mediated N-cadherin (N-CDH) knockdown and an inhibitor, LY294002, were used to further investigate the role of N-CDH and the PI3K/Akt pathway in this process. Results: Dynamic compression better maintained the expression of cell-specific markers (keratin-19, FOXF1 and PAX1) and matrix macromolecules (aggrecan and collagen II), as well as N-CDH expression and the activity of the PI3K/Akt pathway, in the 3D-cultured NP cells compared with those expression levels and activity in the cells grown under static compression. Further analysis showed that the N-CDH knockdown significantly down-regulated the expression of NP cell-specific markers and matrix macromolecules and inhibited the activation of the PI3K/Akt pathway under dynamic compression. However, inhibition of the PI3K/Akt pathway had no effects on N-CDH expression but down-regulated the expression of NP cell-specific markers and matrix macromolecules under dynamic compression. Conclusion: Dynamic compression increases the matrix synthesis of 3D-cultured NP cells compared with that of the cells under static compression, and the N-CDH-PI3K/Akt pathway is involved in this regulatory process. This study provides a promising strategy to promote the matrix deposition of tissue-engineered NP tissue in vitro prior to clinical transplantation.

scholarly journals Chitosan-Based Thermo-Sensitive Hydrogel Loading Oyster Peptides for Hemostasis Application

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5038
Author(s):  
Dongying Zhang ◽  
Zhang Hu ◽  
Lingyu Zhang ◽  
Sitong Lu ◽  
Fengyan Liang ◽  
...  
Keyword(s):  
Matrix Material ◽  
Safety Evaluation ◽  
Massive Hemorrhage ◽  
Gelatin Sponge ◽  
Glycerol Phosphate ◽  
Modified Chitosan ◽  
The Matrix ◽  
Adsorption Rates

Uncontrolled massive hemorrhage is one of the principal causes of death in trauma emergencies. By using catechol-modified chitosan (CS-C) as the matrix material and β glycerol phosphate (β-GP) as a thermo-sensitive agent, chitosan-based thermo-sensitive hydrogel loading oyster peptides (CS-C/OP/β-GP) were prepared at physiological temperature. The hemostatic performance of CS-C/OP/β-GP hydrogel was tested in vivo and in vitro, and its biological safety was evaluated. The results showed that the in vitro coagulation time and blood coagulation index of CS-C/OP/β-GP hydrogel were better than those of a commercial gelatin sponge. Notably, compared with the gelatin sponge, CS-C/OP/β-GP hydrogel showed that the platelet adhesion and erythrocyte adsorption rates were 38.98% and 95.87% higher, respectively. Additionally, the hemostasis time in mouse liver injury was shortened by 19.5%, and the mass of blood loss in the mouse tail amputation model was reduced by 18.9%. The safety evaluation results demonstrated that CS-C/OP/β-GP had no cytotoxicity to L929 cells, and the hemolysis rates were less than 5% within 1 mg/mL, suggesting good biocompatibility. In conclusion, our results indicate that CS-C/OP/β-GP is expected to be a promising dressing in the field of medical hemostasis.

scholarly journals Mean deformation metrics for quantifying 3D cell–matrix interactions without requiring information about matrix material properties

2016 ◽  
Vol 113 (11) ◽  
pp. 2898-2903 ◽  
Author(s):  
David A. Stout ◽  
Eyal Bar-Kochba ◽  
Jonathan B. Estrada ◽  
Jennet Toyjanova ◽  
Haneesh Kesari ◽  
...  
Keyword(s):  
Matrix Material ◽  
Traction Force ◽  
Constitutive Law ◽  
Small Cells ◽  
Collagen Gels ◽  
Cellular Processes ◽  
Physiological Relevance ◽  
Cell Traction ◽  
The Matrix

Mechanobiology relates cellular processes to mechanical signals, such as determining the effect of variations in matrix stiffness with cell tractions. Cell traction recorded via traction force microscopy (TFM) commonly takes place on materials such as polyacrylamide- and polyethylene glycol-based gels. Such experiments remain limited in physiological relevance because cells natively migrate within complex tissue microenvironments that are spatially heterogeneous and hierarchical. Yet, TFM requires determination of the matrix constitutive law (stress–strain relationship), which is not always readily available. In addition, the currently achievable displacement resolution limits the accuracy of TFM for relatively small cells. To overcome these limitations, and increase the physiological relevance of in vitro experimental design, we present a new approach and a set of associated biomechanical signatures that are based purely on measurements of the matrix's displacements without requiring any knowledge of its constitutive laws. We show that our mean deformation metrics (MDM) approach can provide significant biophysical information without the need to explicitly determine cell tractions. In the process of demonstrating the use of our MDM approach, we succeeded in expanding the capability of our displacement measurement technique such that it can now measure the 3D deformations around relatively small cells (∼10 micrometers), such as neutrophils. Furthermore, we also report previously unseen deformation patterns generated by motile neutrophils in 3D collagen gels.

scholarly journals Engineered PLGA-PVP/VA based formulations to produce electro-drawn fast biodegradable microneedles for labile biomolecule delivery

2020 ◽  
Vol 9 (4) ◽  
pp. 203-217
Author(s):  
Valentina Onesto ◽  
Concetta Di Natale ◽  
Martina Profeta ◽  
Paolo Antonio Netti ◽  
Raffaele Vecchione
Keyword(s):  
Matrix Material ◽  
Entrapment Efficiency ◽  
Active Pharmaceutical Ingredient ◽  
Release Profile ◽  
Drug Release Profile ◽  
The Matrix ◽  
Emulsion Formulation ◽  
Industrial Needs ◽  
Mild Temperature

AbstractBiodegradable polymer microneedles (MNs) are recognized as non-toxic, safe and stable systems for advanced drug delivery and cutaneous treatments, allowing a direct intradermal delivery and in some cases a controlled release. Most of the microneedles found in the literature are fabricated by micromolding, which is a multistep thus typically costly process. Due to industrial needs, mold-free methods represent a very intriguing approach in microneedle fabrication. Electro-drawing (ED) has been recently proposed as an alternative fast, mild temperature and one-step strategy to the mold-based techniques for the fabrication of poly(lactic-co-glycolic acid) (PLGA) biodegradable MNs. In this work, taking advantage of the flexibility of the ED technology, we engineered microneedle inner microstructure by acting on the water-in-oil (W/O) precursor emulsion formulation to tune drug release profile. Particularly, to promote a faster release of the active pharmaceutical ingredient, we substituted part of PLGA with poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA), as compared to the PLGA alone in the matrix material. Moreover, we introduced lecithin and maltose as emulsion stabilizers. Microneedle inner structural analysis as well as collagenase entrapment efficiency, release and activity of different emulsion formulations were compared to reach an interconnected porosity MN structure, aimed at providing an efficient protein release profile. Furthermore, MN mechanical properties were examined as well as its ability to pierce the stratum corneum on a pig skin model, while the drug diffusion from the MN body was monitored in an in vitro collagen-based dermal model at selected time points.

scholarly journals Study of Drug Release Kinetics from Sustained Release Matrix Tablets of Acyclovir using Natural Polymer Obtained from Colocasia Esculenta

2020 ◽  
Vol 13 (3) ◽  
pp. 172-179
Author(s):  
Dharmendra Solanki ◽  
Mohit Motiwale ◽  
Sujata Mahapatra
Keyword(s):  
Drug Release ◽  
Sustained Release ◽  
Release Kinetics ◽  
Matrix Material ◽  
Colocasia Esculenta ◽  
Matrix Tablets ◽  
Wet Granulation ◽  
The Matrix ◽  
Release Data

Sustained-release (SR) matrix tablets of Acyclovir and polysaccharide isolated from corms of Colocasia esculenta, at different drug to polymer ratios, were prepared by using wet granulation method. The formulated tablets were also characterized by physical and chemical parameters and results were found in acceptable limits. The investigation focuses on the influence of the proportion of the matrix material on the mechanism and the release rate of the drug from the tablets. In vitro drug release appears to occur both by diffusion and a swelling-controlled mechanism, indicates the drug release from the tablet was non-Fickian super case II transport. The drug release data fit well to the Zero-order drug release Model and the Korsmeyer equation.

Decellularized matrix of the small intestine. Technology for obtaining, evaluating and using directions

2020 ◽  
Vol 22 (4) ◽  
pp. 87-90
Author(s):  
A. A. Kokorina ◽  
S. V. Kromsky ◽  
A. V. Kriventsov ◽  
E. V. Mikhailova ◽  
N. V. Pak ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Small Intestine ◽  
Ex Vivo ◽  
Matrix Material ◽  
Tissue Scaffold ◽  
The Matrix ◽  
Organ Tissue ◽  
Exogenous Origin ◽  
Bioresorbable Material ◽  
Technology Matrix

Matrix (scaffold, matrix, framework, template) is a bioresorbable or non-bioresorbable material that can be filled with stem or somatic cells in/ex vivo in order to obtain a tissue-engineering structure for restoration of a lost organ, part of an organ, tissue. Scaffold must be to the extent necessary strong, non-immunogenic, bioactive. The porosity of the matrix must be open, the surface is rough and, most importantly, the matrix must contain factors of chemotaxis of endo- or exogenous origin, cell adhesion of their proliferation, differentiation. In this context, on the example of creating a decellularized small intestine matrix, a number of fundamental issues are highlighted regarding the choice of matrix material, its production technology, matrix evaluation in accordance with the criteria that correspond to the matrix for tissue engineering, and possible directions for its use. As a result, a non-immunogenic extracellular matrix of the small intestine was obtained by the method of detergent-enzymatic perfusion decellularization, which was sufficient in characteristics for use in various areas of tissue engineering, including plasty of defects of the skin, mucous membranes, small intestine, etc.

scholarly journals Accumulation of PDGF B and cell-binding forms of PDGF A in the extracellular matrix.

1993 ◽  
Vol 121 (5) ◽  
pp. 1153-1163 ◽  
Author(s):  
J L Kelly ◽  
A Sánchez ◽  
G S Brown ◽  
C N Chesterman ◽  
M J Sleigh
Keyword(s):  
Matrix Material ◽  
Cell Types ◽  
Cell Binding ◽  
Laser Confocal Microscopy ◽  
Primary Transcript ◽  
Matrix Deposition ◽  
Cell Extracts ◽  
Binding Forms ◽  
Attachment Sites ◽  
The Matrix

PDGF is a powerful mitogen initially identified within platelets, but also shown to be produced by a wide variety of cell types. PDGF is encoded on two separate genes. These give rise to three polypeptides, PDGF B and two forms of PDGF A (SA and LA), resulting from alternative splicing of the PDGF A gene primary transcript. We report that in CHO cells transfected with PDGF gene constructs and producing moderate levels of PDGF homodimers, much of the PDGF LA and B produced, but little if any SA, is found in the matrix laid down beneath the cells. Immunoreactive PDGF in cells, and in matrix below expressing cells, was visualized by laser confocal microscopy. Western blotting of protein in matrix extracts, cell extracts, and secreted into the growth medium was used to demonstrate that the range of PDGF A polypeptides seen in the matrix was overlapping with those reported previously to be cell associated in cell types such as NIH3T3 and COS 7. This suggests that attachment to matrix or cell surface may be alternative fates for these polypeptides, with fate dependent on the characteristics of the producing cells. Immunoreactive PDGF A and B could be partially released by incubation of matrix material with heparin but not with other glycosaminoglycans. Digestion of matrix with chondroitin ABC lyase but not heparitinase or collagenase displaced some PDGF from its attachment sites. The results indicate attachment of PDGF to matrix proteoglycans, at least partly through the glycosaminoglycan moieties, and perhaps to additional components. The significance of matrix deposition for PDGF action is discussed.

Concept and Overview of Rigid Rod Molecular Composites

1988 ◽  
Vol 134 ◽  
Author(s):  
Wen-Fang Hwang ◽  
T. E. Helminiak
Keyword(s):  
Matrix Material ◽  
Extreme Environments ◽  
Material Technology ◽  
Thermal Expansion Coefficients ◽  
Aspect Ratios ◽  
Rigid Rods ◽  
The Matrix ◽  
Molecular Composites ◽  
Rigid Rod ◽  
New Generation

Recently, the concept of rigid rod molecular composites, originally demonstrated in the Air Force Materials Laboratory, has attracted wide spread attention in the global research community in the hope of creating a new generation of materials for structural and electronic applications in extreme environments. As originally conceived, a molecular composite is a homogeneous, synergistic composite of molecularly dispersed rigid rod polymer molecules (single molecules or small bundles of molecules with a lateral dimension of less than 50 Å) with high aspect ratios in a matrix material. The enhanced and desirable properties, such as superior chemical and environmental resistance, enhanced thermal and thermoxidative stability, toughness, and dimensional stability, resulting from the synergism between the reinforcing rigid rods and the matrix can only be realized in a true molecular composite. Without the development of true rigid rod molecular composite technology, the fundamental detrimental interfacial problems (adhesion, different thermal expansion coefficients, etc.) encountered in conventional fiber composites can not be averted. A truly revolutionary material technology can be developed only if one adheres to the original concept.

scholarly journals In VivoandIn VitroStudy of a Polylactide-Fiber-Reinforcedβ-Tricalcium Phosphate Composite Cage in an Ovine Anterior Cervical Intercorporal Fusion Model

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Janek Frantzén ◽  
Aliisa Pälli ◽  
Esa Kotilainen ◽  
Harri Heino ◽  
Bettina Mannerström ◽  
...  
Keyword(s):  
Tricalcium Phosphate ◽  
Bone Growth ◽  
Matrix Material ◽  
Fusion Model ◽  
Bone Contact ◽  
Osteogenic Effect ◽  
A Minor ◽  
Intercorporal Fusion

A poly-70L/30DL-lactide (PLA70)–β-tricalcium phosphate (β-TCP) composite implant reinforced by continuous PLA-96L/4D-lactide (PLA96) fibers was designed forin vivospinal fusion. The pilot study was performed with four sheep, using titanium cage implants as controls. The composite implants failed to direct bone growth as desired, whereas the bone contact and the proper integration were evident with controls 6 months after implantation. Therefore, the PLA70/β-TCP composite matrix material was further analyzed in thein vitroexperiment by human and ovine adipose stem cells (hASCs and oASCs). The composites proved to be biocompatible as confirmed by live/dead assay. The proliferation rate of oASCs was higher than that of hASCs at all times during the 28 d culture period. Furthermore, the composites had only a minor osteogenic effect on oASCs, whereas the hASC osteogenesis on PLA70/β-TCP composites was evident. In conclusion, the composite implant material can be applied with hASCs for tissue engineering but not be evaluatedin vivowith sheep.

An Experimental Study of Wedge Indentation of Porous Solids: Implications for Cutting and Drilling Processes

2018 ◽  
Author(s):  
Shwetabh Yadav ◽  
Tejas G. Murthy ◽  
Dinakar Sagapuram
Keyword(s):  
Experimental Study ◽  
Deformation Zone ◽  
Measurement Techniques ◽  
Matrix Material ◽  
Porous Solids ◽  
Radial Compression ◽  
Compaction Bands ◽  
The Matrix ◽  
Flow Features ◽  
Wedge Indentation

An experimental study of mechanics of wedge indentation of porous solids is carried out under plane-strain conditions. A comparison is made between the porous ductile copper and porous brittle gypsum to study the influence of matrix material on the indentation behavior. Image-based measurement techniques are used to capture the evolution of deformation zone and obtain quantitative velocity, strain and volume change fields at high resolution. The results show that despite widely-different characteristics of the matrix material, the overall deformation zone evolves in a manner that is largely similar across material systems. Porous copper exhibits a smoothly-varying radial compression-type plastic flow within the deformation zone, while localized flow features (compaction bands) are typical of gypsum. Implications of our observations on wedge indentation for modeling complex machining geometries such as cutting and drilling are briefly discussed.

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