Development of a Hydroxyapatite Bone Tissue Engineering Scaffold with a Trimodal Pore Structure

2007 ◽  
Vol 361-363 ◽  
pp. 931-934 ◽  
Author(s):  
Conor T. Buckley ◽  
K.U. O’Kelly
Keyword(s):  
Tissue Engineering ◽  
Cell Viability ◽  
Porous Scaffold ◽  
Tissue Engineering Scaffold ◽  
Porous Scaffolds ◽  
Cell Penetration ◽  
Nutrient Delivery ◽  
And Migration

Tissue-engineering scaffold-based strategies have suffered from limited cell depth viability when cultured in vitro, with viable cells existing within the outer 250-500μm from the fluid-scaffold interface. This is primarily believed to be due to the lack of nutrient delivery into and waste removal from the inner regions of the scaffold construct. Other issues associated with porous scaffolds involve poor seeding efficiencies and limited cell penetration resulting in heterogeneous cellular distributions. This work focuses on the development a novel hydroxyapatite multi-domain porous scaffold architecture (i.e. a scaffold providing a discrete domain for cell occupancy and a separate domain for nutrient delivery) with the specific objectives of embodying in one scaffold the structures required to optimise cell seeding, cell proliferation and migration and potentially to facilitate vascularisation once implanted in vivo. This paper presents the development of the multidomain architecture and preliminary results on cell viability which show a significant improvement in cell viability in the scaffold interiors.

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 Engineered Hypopharynx from Coculture of Epithelial Cells and Fibroblasts Using Poly(ester urethane) as Substratum

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Zhisen Shen ◽  
Jingjing Chen ◽  
Cheng Kang ◽  
Changfeng Gong ◽  
Yabin Zhu
Keyword(s):  
Tissue Engineering ◽  
Epithelial Cells ◽  
Silk Fibroin ◽  
Porous Scaffold ◽  
Engineering Research ◽  
Polymeric Scaffolds ◽  
Cell Tissue ◽  
Silkworm Cocoon

Porous polymeric scaffolds have been much investigated and applied in the field of tissue engineering research. Poly(ester urethane) (PEU) scaffolds, comprising pores of 1–20 μm in diameter on one surface and ≥200 μm on the opposite surface and in bulk, were fabricated using phase separation method for hypopharyngeal tissue engineering. The scaffolds were grafted with silk fibroin (SF) generated from natural silkworm cocoon to enhance the scaffold’s hydrophilicity and further improve cytocompatibility to both primary epithelial cells (ECs) and fibroblasts of human hypopharynx tissue. Coculture of ECs and fibroblasts was conducted on the SF-grafted PEU scaffold (PEU-SF) to evaluate itsin vitrocytocompatibility. After co-culture for 14 days, ECs were lined on the scaffold surface while fibroblasts were distributed in scaffold bulk. The results ofin vivoinvestigation showed that PEU porous scaffold possessed good biocompatibility after it was grafted by silk fibroin. SF grafting improved the cell/tissue infiltration into scaffold bulk. Thus, PEU-SF porous scaffold is expected to be a good candidate to support the hypopharynx regeneration.

scholarly journals Nanoparticles Loaded with the BET Inhibitor JQ1 Block the Growth of Triple Negative Breast Cancer Cells In Vitro and In Vivo

Cancers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 91 ◽  
Author(s):  
Valentina Maggisano ◽  
Marilena Celano ◽  
Rocco Malivindi ◽  
Ines Barone ◽  
Donato Cosco ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Viability ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Anticancer Efficacy ◽  
Bet Inhibitor ◽  
Physico Chemical ◽  
And Migration

Inhibition of bromo-and extra-terminal domain (BET) proteins, epigenetic regulators of genes involved in cell viability, has been efficiently tested in preclinical models of triple negative breast cancer (TNBC). However, the use of the selective BET-inhibitor JQ1 on humans is limited by its very short half-life. Herein, we developed, characterized and tested a novel formulation of nanoparticles containing JQ1 (N-JQ1) against TNBC in vitro and in vivo. N-JQ1, prepared using the nanoprecipitation method of preformedpoly-lactid-co-glycolic acid in an aqueous solution containing JQ1 and poloxamer-188 as a stabilizer, presented a high physico-chemical stability. Treatment of MDA-MB 157 and MDA-MB 231 TNBC cells with N-JQ1 determined a significant decrease in cell viability, adhesion and migration. Intra-peritoneal administration (5 days/week for two weeks) of N-JQ1 in nude mice hosting a xenograft TNBC after flank injection of MDA-MB-231 cells determined a great reduction in the growth and vascularity of the neoplasm. Moreover, the treatment resulted in a minimal infiltration of nearby tissues. Finally, the encapsulation of JQ1 in nanoparticles improved the anticancer efficacy of this epigenetic compound against TNBC in vitro and in vivo, opening the way to test it in the treatment of TNBC.

Biocompatibility and biodegradation properties of polycaprolactone/polydioxanone composite scaffolds prepared by blend or co-electrospinning

2019 ◽  
Vol 34 (2) ◽  
pp. 115-130 ◽  
Author(s):  
Xin Zhou ◽  
Yiwa Pan ◽  
Ruihua Liu ◽  
Xin Luo ◽  
Xianyan Zeng ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Mechanical Strength ◽  
Structural Characteristics ◽  
Tissue Engineering Scaffold ◽  
Morphological Properties ◽  
Composite Scaffolds ◽  
Electrospun Scaffolds ◽  
Hybrid Scaffolds

Electrospun polymer scaffolds are regarded as an ideal tissue engineering scaffold due to similar morphological properties with the native extracellular matrix. Among these, polycaprolactone is widely used to fabricate electrospun fibrous scaffolds due to its excellent biocompatibility, good mechanical properties, and ease of manufacture. However, its low biodegradation rate has a negative influence on its application in tissue engineering scaffold. To address this issue, this study prepared hybrid scaffolds composed of polycaprolactone and polydioxanone (a fast-degrading polyether-ester) via either the blend or co-electrospinning. Subsequently, the structural characteristics, mechanical strength, in vitro/vivo degradation, cellularization, and vascularization of two kinds of hybrid scaffolds were evaluated to decide which method is more suitable for producing tissue engineering scaffolds. The incorporation of polydioxanone increased the mechanical strength of both composite scaffolds. Moreover, co-electrospun scaffolds exhibited improved hydrophilicity compared to blend scaffolds. The results of in vitro and in vivo degradation studies showed that the degradation rate of both composite scaffolds was faster than that of neat polycaprolactone scaffolds due to the incorporated polydioxanone component. Especially in co-electrospun scaffolds, the fast degradation of polydioxanone fiber gave rise to larger pore size, thus leading to faster cellularization and better vascularization compared to blend scaffolds. Therefore, co-electrospinning was demonstrated to be superior to blend electrospinning for the preparation of composite scaffolds. Co-electrospun polycaprolactone–polydioxanone scaffolds may be promising candidates for tissue engineering.

scholarly journals Graphene Coated Scaffold for Bone Tissue Engineering: Physicochemical and Osteogenic Characterizations

2021 ◽  
Author(s):  
Sajad Bahrami ◽  
Nafiseh Baheiraei ◽  
Mostafa Shahrezaee
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Cranial Bone ◽  
Drying Methods ◽  
Porous Scaffolds ◽  
Alizarin Red

Abstract Variety of bone-related diseases and injures and limitations of traditional regeneration methods need to introduce new tissue substitutes. Tissue engineering and regeneration combined with nanomedicine can provide different natural or synthetic and combined scaffolds with bone mimicking properties for implant in the injured area. In this study, we synthesized collagen (Col) and reduced graphene oxide coated collagen (Col-rGO) scaffolds and evaluated their in vitro and in vivo effects on bone tissue repair. Col and Col-rGO scaffolds were synthesized by chemical crosslinking and freeze-drying methods. The surface topography, mechanical and chemical properties of scaffolds were characterized and showed three-dimensional (3D) porous scaffolds and successful coating of rGO on Col. rGO coating enhanced mechanical strength of Col-rGO scaffolds compared with Col scaffolds by 2.8 folds. Furthermore, Col-rGO scaffolds confirmed that graphene addition not only did not any cytotoxic effects but also enhanced human bone marrow-derived mesenchymal stem cells (hBMSCs) viability and proliferation with 3D adherence and expansion. Finally, scaffolds implantation into rabbit cranial bone defect for 12 weeks showed increased bone formation, confirmed by Hematoxylin-Eosin (H&E) and alizarin red staining. Altogether, the study showed that rGO coating improves Col scaffold properties and could be a promising implant for bone injuries.

Bio-Testing of Poly-L-Lactic Acid/Hydroxyapatite Porous Bone Scaffolds

2011 ◽  
Author(s):  
Qingwei Zhang ◽  
Wei Zhang ◽  
Jephte Augustin ◽  
Donggang Yao ◽  
David M. Wootton ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Lactic Acid ◽  
Porous Structure ◽  
Bone Tissue ◽  
Bone Architecture ◽  
Porous Scaffolds ◽  
Porous Structures ◽  
Sacrificial Material

Tissue engineering is a rapidly growing interdisciplinary field which offers a promising new technology to create artificial constructs for regeneration of tissues. One important aspect of bone tissue engineering is to build scaffolds with interconnected 3-D porous structure in order to mimic natural bone architecture. In this work, co-continuous micro-porous scaffolds made of Poly-L-lactic acid (PLLA) with 50% porosity and PLLA/hydroxyapatite (HA) with 40% porosity were prepared by injection molding of an immiscible polymer blend with polystyrene as sacrificial material. The sacrificial material was then removed by solvent leaching with cyclohexane. The porous PLLA/HA matrix supported murine osteoblast (7F2) cell growth for up to 9 days, suggesting that that the introduction and replacement of sacrificial material had no negative effects on cell proliferation. In vitro studies also indicate an increase in mineralization by osteoblasts cultured on the porous structure, as compared to cells cultured on solid scaffold. One month subcutaneous degradation tests showed a mild foreign body reaction and complete fibrous encapsulation. Following surgical implantation of the scaffolds into circular defects in canine tibia, we observed after 12 weeks new bone tissue grew into the porous structures. Taken together our data suggest that interconnected porous structures with good cytocompatibility and increased mineralization in vitro paired with enhanced osteoinductive properties in vivo suggest a great potential of the porous PLLA/HA for inducing and sustaining bone tissue repair.

A Finite Element Prediction of Strain on Cells in a Highly Porous Collagen-Glycosaminoglycan Scaffold

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
A. J. F. Stops ◽  
L. A. McMahon ◽  
D. O’Mahoney ◽  
P. J. Prendergast ◽  
P. E. McHugh
Keyword(s):  
Tissue Engineering ◽  
Finite Element ◽  
Load Transfer ◽  
Porous Scaffold ◽  
Computational Prediction ◽  
Element Model ◽  
Porous Scaffolds ◽  
Wide Range ◽  
A Cell

Tissue engineering often involves seeding cells into porous scaffolds and subjecting the scaffold to mechanical stimulation. Current experimental techniques have provided a plethora of data regarding cell responses within scaffolds, but the quantitative understanding of the load transfer process within a cell-seeded scaffold is still relatively unknown. The objective of this work was to develop a finite element representation of the transient and heterogeneous nature of a cell-seeded collagen-GAG-scaffold. By undertaking experimental investigation, characteristics such as scaffold architecture and shrinkage, cellular attachment patterns, and cellular dimensions were used to create a finite element model of a cell-seeded porous scaffold. The results demonstrate that a very wide range of microscopic strains act at the cellular level when a sample value of macroscopic (apparent) strain is applied to the collagen-GAG-scaffold. An external uniaxial strain of 10% generated a cellular strain as high as 49%, although the majority experienced less than ∼5% strain. The finding that the strain on some cells could be higher than the macroscopic strain was unexpected and proves contrary to previous in vitro investigations. These findings indicate a complex system of biophysical stimuli created within the scaffolds and the difficulty of inducing the desired cellular responses from artificial environments. Future in vitro studies could also corroborate the results from this computational prediction to further explore mechanoregulatory mechanisms in tissue engineering.

scholarly journals Three dimensional porous scaffolds derived from collagen, elastin and fibrin proteins orchestrate adipose tissue regeneration

2021 ◽  
Vol 12 ◽  
pp. 204173142110192
Author(s):  
Prasad Sawadkar ◽  
Nandin Mandakhbayar ◽  
Kapil D Patel ◽  
Jennifer Olmas Buitrago ◽  
Tae Hyun Kim ◽  
...  
Keyword(s):  
Stem Cells ◽  
Soft Tissue ◽  
Porous Scaffold ◽  
Pathological Condition ◽  
Donor Site ◽  
Porous Scaffolds ◽  
Adipose Derived Stem Cells ◽  
Natural Polymers

Current gold standard to treat soft tissue injuries caused by trauma and pathological condition are autografts and off the shelf fillers, but they have inherent weaknesses like donor site morbidity, immuno-compatibility and graft failure. To overcome these limitations, tissue-engineered polymers are seeded with stem cells to improve the potential to restore tissue function. However, their interaction with native tissue is poorly understood so far. To study these interactions and improve outcomes, we have fabricated scaffolds from natural polymers (collagen, fibrin and elastin) by custom-designed processes and their material properties such as surface morphology, swelling, wettability and chemical cross-linking ability were characterised. By using 3D scaffolds, we comprehensive assessed survival, proliferation and phenotype of adipose-derived stem cells in vitro. In vivo, scaffolds were seeded with adipose-derived stem cells and implanted in a rodent model, with X-ray microtomography, histology and immunohistochemistry as read-outs. Collagen-based materials showed higher cell adhesion and proliferation in vitro as well as higher adipogenic properties in vivo. In contrast, fibrin demonstrated poor cellular and adipogenesis properties but higher angiogenesis. Elastin formed the most porous scaffold, with cells displaying a non-aggregated morphology in vitro while in vivo elastin was the most degraded scaffold. These findings of how polymers present in the natural polymers mimicking ECM and seeded with stem cells affect adipogenesis in vitro and in vivo can open avenues to design 3D grafts for soft tissue repair.

scholarly journals Poly(lactide- co -glycolide) porous scaffolds for tissue engineering and regenerative medicine

2012 ◽  
Vol 2 (3) ◽  
pp. 366-377 ◽  
Author(s):  
Zhen Pan ◽  
Jiandong Ding
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Regenerative Medicine ◽  
Porous Scaffolds ◽  
Plga Scaffold ◽  
Degradation Rates ◽  
Long Time ◽  
Facile Fabrication

Porous scaffolds fabricated from biocompatible and biodegradable polymers play vital roles in tissue engineering and regenerative medicine. Among various scaffold matrix materials, poly(lactide- co -glycolide) (PLGA) is a very popular and an important biodegradable polyester owing to its tunable degradation rates, good mechanical properties and processibility, etc. This review highlights the progress on PLGA scaffolds. In the latest decade, some facile fabrication approaches at room temperature were put forward; more appropriate pore structures were designed and achieved; the mechanical properties were investigated both for dry and wet scaffolds; a long time biodegradation of the PLGA scaffold was observed and a three-stage model was established; even the effects of pore size and porosity on in vitro biodegradation were revealed; the PLGA scaffolds have also been implanted into animals, and some tissues have been regenerated in vivo after loading cells including stem cells.

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