scholarly journals Porous Geometry Guided Micro-mechanical Environment Within Scaffolds for Cell Mechanobiology Study in Bone Tissue Engineering

2021 ◽  
Vol 9 ◽  
Author(s):  
Feihu Zhao ◽  
Yi Xiong ◽  
Keita Ito ◽  
Bert van Rietbergen ◽  
Sandra Hofmann
Keyword(s):  
Porous Scaffold ◽  
Mechanical Strain ◽  
Three Dimensional ◽  
Pore Geometry ◽  
Cell Physiology ◽  
Porous Scaffolds ◽  
Mechanical Environment ◽  
Functional Features ◽  
Future Work

Mechanobiology research is for understanding the role of mechanics in cell physiology and pathology. It will have implications for studying bone physiology and pathology and to guide the strategy for regenerating both the structural and functional features of bone. Mechanobiological studies in vitro apply a dynamic micro-mechanical environment to cells via bioreactors. Porous scaffolds are commonly used for housing the cells in a three-dimensional (3D) culturing environment. Such scaffolds usually have different pore geometries (e.g. with different pore shapes, pore dimensions and porosities). These pore geometries can affect the internal micro-mechanical environment that the cells experience when loaded in the bioreactor. Therefore, to adjust the applied micro-mechanical environment on cells, researchers can tune either the applied load and/or the design of the scaffold pore geometries. This review will provide information on how the micro-mechanical environment (e.g. fluid-induced wall shear stress and mechanical strain) is affected by various scaffold pore geometries within different bioreactors. It shall allow researchers to estimate/quantify the micro-mechanical environment according to the already known pore geometry information, or to find a suitable pore geometry according to the desirable micro-mechanical environment to be applied. Finally, as future work, artificial intelligent – assisted techniques, which can achieve an automatic design of solid porous scaffold geometry for tuning/optimising the micro-mechanical environment are suggested.

Development of HA-PLGA Scaffold Encapsulating Intact BMP-2 Using Solid Freeform Fabrication Technology

2011 ◽  
Author(s):  
Jin-Hyung Shim ◽  
Jong Young Kim ◽  
Kyung Shin Kang ◽  
Jung Kyu Park ◽  
Sei Kwang Hahn ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bone Regeneration ◽  
Porous Scaffold ◽  
Solid Freeform Fabrication ◽  
Three Dimensional ◽  
Porous Scaffolds ◽  
Prolonged Release ◽  
Cellular Activity ◽  
Freeform Fabrication

Tissue engineering is an interdisciplinary field that focuses on restoring and repairing tissues or organs. Cells, scaffolds, and biomolecules are recognized as three main components of tissue engineering. Solid freeform fabrication (SFF) technology is required to fabricate three-dimensional (3D) porous scaffolds to provide a 3D environment for cellular activity. SFF technology is especially advantageous for achieving a fully interconnected, porous scaffold. Bone morphogenic protein-2 (BMP-2), an important biomolecule, is widely used in bone tissue engineering to enhance bone regeneration activity. However, methods for the direct incorporation of intact BMP-2 within 3D scaffolds are rare. In this work, 3D porous scaffolds with poly(lactic-co-glycolic acid) chemically grafted hyaluronic acid (HA-PLGA), in which intact BMP-2 was directly encapsulated, were successfully fabricated using SFF technology. BMP-2 was previously protected by poly(ethylene glycol) (PEG), and the BMP-2/PEG complex was incorporated in HA-PLGA using an organic solvent. The HAPLGA/PEG/BMP-2 mixture was dissolved in chloroform and deposited via a multi-head deposition system (MHDS), one type of SFF technology, to fabricate a scaffold for tissue engineering. An additional air blower system and suction were installed in the MHDS for the solvent-based fabrication method. An in vitro evaluation of BMP-2 release was conducted, and prolonged release of intact BMP-2, for up to 28 days, was confirmed. After confirmation of advanced proliferation of pre osteoblasts, a superior differentiation effect of the HA-PLGA/PEG/BMP-2 scaffold was validated by measuring high expression levels of bone-specific markers, such as alkaline phosphatase (ALP) and osteocalcin (OC). We show that our solvent-based fabrication is a non-toxic method for restoring cellular activity. Moreover, the HAPLGA/PEG/BMP-2 scaffold was effective for bone regeneration.

scholarly journals Label-free magnetic resonance imaging to locate live cells in three-dimensional porous scaffolds

2012 ◽  
Vol 9 (74) ◽  
pp. 2321-2331 ◽  
Author(s):  
A. Abarrategi ◽  
M. E. Fernandez-Valle ◽  
T. Desmet ◽  
D. Castejón ◽  
A. Civantos ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Porous Scaffold ◽  
Three Dimensional ◽  
Live Cells ◽  
Porous Scaffolds ◽  
Label Free ◽  
Resonance Imaging ◽  
Critical Feature

Porous scaffolds are widely tested materials used for various purposes in tissue engineering. A critical feature of a porous scaffold is its ability to allow cell migration and growth on its inner surface. Up to now, there has not been a method to locate live cells deep inside a material, or in an entire structure, using real-time imaging and a non-destructive technique. Herein, we seek to demonstrate the feasibility of the magnetic resonance imaging (MRI) technique as a method to detect and locate in vitro non-labelled live cells in an entire porous material. Our results show that the use of optimized MRI parameters (4.7 T; repetition time = 3000 ms; echo time = 20 ms; resolution 39 × 39 µm) makes it possible to obtain images of the scaffold structure and to locate live non-labelled cells in the entire material, with a signal intensity higher than that obtained in the culture medium. In the current study, cells are visualized and located in different kinds of porous scaffolds. Moreover, further development of this MRI method might be useful in several three-dimensional biomaterial tests such as cell distribution studies, routine qualitative testing methods and in situ monitoring of cells inside scaffolds.

scholarly journals COMPARATIVE ANALYSIS OF THREE-DIMENSIONAL NANOSTRUCTURE OF POROUS BIOCOMPATIBLE SCAFFOLDS MADE OF RECOMBINANT SPIDROIN AND SILK FIBROIN FOR REGENERATIVE MEDICINE

2015 ◽  
Vol 17 (2) ◽  
pp. 37-44 ◽  
Author(s):  
O. I. Agapova ◽  
A. E. Efimov ◽  
M. M. Moisenovich ◽  
V. G. Bogush ◽  
I. I. Agapov
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Scanning Probe ◽  
Porous Scaffolds ◽  
Volume Porosity ◽  
Integral Density ◽  
Regenerative Activity ◽  
Calculated Volume ◽  
Recombinant Spidroin

Aim.To perform a comparison of three-dimensional nanostructure of porous biocompatible scaffolds made of fibroinBombix moriand recombinant spidroin rS1/9.Materials and methods.Three-dimensional porous scaffolds were produced by salt leaching technique. The comparison of biological characteristics of the scaffolds shows that adhesion and proliferation of mouse fibroblastsin vitroon these two types of scaffolds do not differ significantly. Comparative experimentsin vivoshow that regeneration of bone tissue of rats is faster with implantation of recombinant spidroin scaffolds. Three-dimensional nanostructure of scaffolds and interconnectivity of nanopores were studied with scanning probe nanotomography (SPNT) to explain higher regenerative activity of spidroin-based scaffolds.Results.Significant differences were detected in the integral density and volume of pores: the integral density of nanopores detected on 2D AFM images is 46 μm–2    and calculated volume porosity is 24% in rS1/9-based scaffolds; in fibroin-based three-dimensional structures density of nanopores and calculated volume porosity were 2.4 μm–2  and 0.5%, respectively. Three-dimensional reconstruction system of nanopores and clusters of interconnected nanopores in rS1/9-based scaffolds showed that volume fraction of pores interconnected in percolation clusters is 35.3% of the total pore volume or 8.4% of the total scaffold volume.Conclusion.Scanning probe nanotomography method allows obtaining unique information about topology of micro – and nanopore systems of artificial biostructures. High regenerative activity of rS1/9-based scaffolds can be explained by higher nanoporosity of the scaffolds.

Preparation and Characterization of Ha/Gel/β-TCP Microspheres Composite Porous Scaffold

2018 ◽  
Vol 782 ◽  
pp. 103-115
Author(s):  
Yang Zi Zhao ◽  
You Fa Wang
Keyword(s):  
Tissue Engineering ◽  
Compressive Strength ◽  
Hyaluronic Acid ◽  
Pore Size ◽  
Porous Scaffold ◽  
Three Dimensional ◽  
Swelling Ratio ◽  
Cell Compatibility ◽  
Hydrogel Scaffolds

Being one of the three elements of tissue engineering, three-dimensional porous structure scaffold plays an important role in tissue engineering. As it not only prvovide cells for the life, but also serves as a template to guide tissue regeneration and control of organizational structure and other functions. In this study, hyaluronic acid and gelatin are successfully cross-linked by 1-ethyl- (3-dimethylaminopropyl) -carbodiimide hydrochloride (EDC) , and compound β-TCP microspheres to prepare porous hydrogel scaffolds. The microspheres were analyzed by X-ray diffraction (XRD). The scaffolds were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). At the same time, the compressive strength, swelling ratio, degradation of the scaffold were tested. To assess the in vitro cell compatibility of the scaffolds, mouse L929 fibroblasts were seeded onto scaffolds for cell morphology and cell viability studies. The results showed that the pore size of the porous scaffold can be adjusted by changing the ratio of gelatin to hyaluronic acid (HA), increasing the proportion of hyaluronic acid in a certain range, pore size will be significantly increased. With the increase of the proportion of hyaluronic acid in the scaffold, the swelling ratio and the degradation rate also increased. The compressive strength of the scaffold increased with the increase of the proportion of gelatin. The appropriate ratio of β-TCP can promote cell growth and proliferation.

scholarly journals Development and AFM study of porous scaffolds for wound healing applications

2004 ◽  
Vol 18 (4) ◽  
pp. 587-596 ◽  
Author(s):  
T. A. Doneva ◽  
H. B. Yin ◽  
P. Stephens ◽  
W. R. Bowen ◽  
D. W. Thomas
Keyword(s):  
Atomic Force Microscopy ◽  
Wound Healing ◽  
Human Fibroblasts ◽  
Three Dimensional ◽  
Positive Influence ◽  
Porous Scaffolds ◽  
Force Microscopy ◽  
Cellular Assays ◽  
Atomic Force

An engineering approach to the development of biomaterials for promotion of wound healing emphasises the importance of a well‒controlled architecture and concentrates on optimisation of morphology and surface chemistry to stimulate guidance of the cells within the wound environment. A series of three‒dimensional porous scaffolds with 80–90% bulk porosity and fully interconnected macropores were prepared from two biodegradable materials – cellulose acetate (CA) and poly (lactic‒co‒glycolic acid) (PLGA) through the phase inversion mechanism of formation. Surface morphology of obtained scaffolds was determined using atomic force microscopy (AFM) in conjunction with optical microscopy. Scanning Electron Microscopy (SEM) was applied to characterise scaffolds bulk morphology. Biocompatibility and biofunctionality of the prepared materials were assessed through a systematic study of cell/material interactions using atomic force microscopy (AFM) methodologies together within vitrocellular assays. Preliminary data with human fibroblasts demonstrated a positive influence of both scaffolds on cellular attachment and growth. The adhesion of cells on both biomaterials were quantified by AFM force measurements in conjunction with a cell probe technique since, for the first time, a fibroblast probe has been successfully developed and optimal conditions of immobilisation of the cells on the AFM cantilever have been experimentally determined.

Rapid characterization of candidate loss of function genes in primary organoid culture.

2017 ◽  
Vol 35 (4_suppl) ◽  
pp. 77-77
Author(s):  
Daniel James Hart ◽  
Ameen Abdulla Salahudeen ◽  
Sean de la O ◽  
Kyuho Han ◽  
David Morgens ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Suitable Model ◽  
Loss Of Function ◽  
Synonymous Mutations ◽  
Functional Control ◽  
Rapid Characterization ◽  
Air Liquid Interface ◽  
Shrna Screen ◽  
Future Work

77 Background: Genome scale sequencing efforts have identified chromosomal deletions and non-synonymous mutations as putative drivers of gastro-intestinal cancer. There is a need to rapidly validate these drivers in robust models. The culture of primary, non-transformed tissues in vitro as three-dimensional organoids that accurately recapitulate organ structure and physiology serves as an ideal model for such validation, and many other applications in biology. Methods: Mouse wild type and p53 flox/flox upper digestive tract tissue containing epithelial and mesenchymal components were cultured in an air-liquid interface and subjected to adenovirus expressing either a functional control or Cre recombinase. Resultant organoids were passaged at confluency until dysplasia was evident in histology. A lentiviral shRNA (loss-of-function) screen was then conducted, where proliferative activity was measured with barcode reads from the pooled library. Results: p53-null organoids showed histology consistent with human gastrointestinal cancer. These organoids were also able to form small tumors when injected subcutaneously into immune-deficient mice. The pooled lentiviral shRNA screen functionally validated candidate drivers. Conclusions: Gastrointestinal organoids are a suitable model for the introduction of oncogenic mutations in a tractable and replicable format. In future work we will validate loss-of function and gain-of-function screens with CRISPRi/a libraries, and replicate these screens in human gastrointestinal organoids.

Microscopic Analysis of Porous Biodegradable Scaffolds for Tissue Engineering

2000 ◽  
Vol 6 (S2) ◽  
pp. 988-989
Author(s):  
F. Buevich ◽  
S. Pulapura ◽  
J. Kohn
Keyword(s):  
Tissue Regeneration ◽  
Combinatorial Library ◽  
Three Dimensional ◽  
Microscopic Analysis ◽  
Porous Scaffolds ◽  
Biodegradable Scaffolds ◽  
Condensation Polymers ◽  
Scaffold Architecture ◽  
Useful Lifetime

Introduction: There is considerable interest in the use of three-dimensional porous scaffolds for tissue regeneration. The presence of an interconnected framework of pores with large surface area facilitates the formation of extracellular matrix and permits cellular ingrowth into implanted structures. For scaffolds to be useful for tissue regeneration, they must maintain good dimensional stability during the lifetime of the implant. While the initial scaffold architecture is often well characterized, a systematic study of the influence of incubation on the scaffold architecture is critical to ensure that the scaffolds retain their interconnected network of pores during their useful lifetime. Herein, we report on the evaluation of the architecture of polyarylate scaffolds and their stability under in vitro conditions using scanning electron microscopy (SEM).The polymers used in this study were selected from a library of degradable polyarylates. This library is the first reported combinatorial library of biodegradable condensation polymers.

scholarly journals Characterization and cytocompatibility of 3D porous biomimetic scaffold derived from rabbit nucleus pulposus tissue in vitro

2021 ◽  
Vol 32 (1) ◽  
Author(s):  
Yu Zhang ◽  
Wei Tan ◽  
Mingxin Wu ◽  
Jin Sun ◽  
Wei Cao ◽  
...  
Keyword(s):  
Nucleus Pulposus ◽  
Porous Scaffold ◽  
Experimental Treatment ◽  
Mechanical Tests ◽  
Control Group ◽  
Porous Scaffolds ◽  
High Porosity ◽  
Marrow Mesenchymal Stem Cells ◽  
Biomimetic Scaffold

Abstract Intervertebral disc (IVD) degeneration is one of the most important causes of lower back pain. Tissue engineering provides a new method for the experimental treatment of degenerative disc diseases. This study aims to develop a natural, acellular, 3D interconnected porous scaffold derived from the extracellular matrix (ECM) of nucleus pulposus. The nucleus pulposus (NP) was decellularized by sequential detergent-nuclease methods, including physical crushing, freeze-drying and cross-linking. These 3D porous scaffolds were fabricated with a high porosity of (81.28 ± 4.10)%, an ideal pore size with appropriate mechanical properties. Rabbit bone marrow mesenchymal stem cells (rBMSCs) were seeded and cultured on the scaffolds. And the mechanical tests showed the compressive elastic modulus of the scaffolds cultured for 4 weeks reached 0.12 MPa, which was better than that of the scaffolds cultured for 2 weeks (0.07 MPa) and that of the control group (0.04 MPa). Scanning electron microscopy (SEM), histological assays, molecular biology assays revealed that the scaffolds could provide an appropriate microstructure and environment for the adhesion, proliferation, migration and secretion of seeded cells in vitro. As assays like histology, immunohistochemistry and the real-time qRT-PCR showed, NP-like tissues were preliminarily formed. In conclusion, the 3D porous scaffold derived from NP ECM is a potential biomaterial for the regeneration of NP tissues.

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