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The fusion of tissue spheroids attached to pre-stretched electrospun polyurethane scaffolds.

Beachley V, Kasyanov V, Nagy-Mehesz A, Norris R, Ozolanta I, Kalejs M, Stradins P, Baptista L, da Silva K, Grainjero J, Wen X, Mironov V - J Tissue Eng (2014)

Bottom Line: Tissue spheroids attached, spread, and fused after being placed on pre-stretched polyurethane electrospun matrices and formed tissue constructs.Efforts to eliminate hole defects with fibrogenic tissue growth factor-β resulted in the increased synthesis of collagen and periostin and a dramatic reduction in hole size and number.In control experiments, tissue spheroids fuse on a non-adhesive hydrogel and form continuous tissue constructs without holes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Rowan University, Glassboro, NJ, USA.

ABSTRACT
Effective cell invasion into thick electrospun biomimetic scaffolds is an unsolved problem. One possible strategy to biofabricate tissue constructs of desirable thickness and material properties without the need for cell invasion is to use thin (<2 µm) porous electrospun meshes and self-assembling (capable of tissue fusion) tissue spheroids as building blocks. Pre-stretched electrospun meshes remained taut in cell culture and were able to support tissue spheroids with minimal deformation. We hypothesize that elastic electrospun scaffolds could be used as temporal support templates for rapid self-assembly of cell spheroids into higher order tissue structures, such as engineered vascular tissue. The aim of this study was to investigate how the attachment of tissue spheroids to pre-stretched polyurethane scaffolds may interfere with the tissue fusion process. Tissue spheroids attached, spread, and fused after being placed on pre-stretched polyurethane electrospun matrices and formed tissue constructs. Efforts to eliminate hole defects with fibrogenic tissue growth factor-β resulted in the increased synthesis of collagen and periostin and a dramatic reduction in hole size and number. In control experiments, tissue spheroids fuse on a non-adhesive hydrogel and form continuous tissue constructs without holes. Our data demonstrate that tissue spheroids attached to thin stretched elastic electrospun scaffolds have an interrupted tissue fusion process. The resulting tissue-engineered construct phenotype is a direct outcome of the delicate balance of the competing physical forces operating during the tissue fusion process at the interface of the pre-stretched elastic scaffold and the attached tissue spheroids. We have shown that with appropriate treatments, this process can be modulated, and thus, a thin pre-stretched elastic polyurethane electrospun scaffold could serve as a supporting template for rapid biofabrication of thick tissue-engineered constructs without the need for cell invasion.

No MeSH data available.


Related in: MedlinePlus

Formation of holes in tissue constructs as a result of incomplete tissue spheroids fusion on pre-stretched electrospun matrix and their dramatic reduction after TGF-β1 treatment. (a) Tissue spheroids placed on electrospun polyurethane scaffold before tissue fusion and without TGF-β1 treatment (control). Scale bar—1 mm. (b) Large holes in the fused tissue construct are formed on the pre-stretched electrospun polyurethane scaffold without TGF-β1 treatment (control). Scale bar—1 mm. (c) Tissue spheroids adherent to the electrospun polyurethane scaffold before tissue fusion and TGF-β1 treatment (experiment). Scale bar—1 mm. (d) A reduction in the size and density of holes in the fused tissue construct on pre-stretched electrospun polyurethane scaffold after TGF-β1 treatment (experiment). Scale bar—1 mm.TGF: tissue growth factor.
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fig5-2041731414556561: Formation of holes in tissue constructs as a result of incomplete tissue spheroids fusion on pre-stretched electrospun matrix and their dramatic reduction after TGF-β1 treatment. (a) Tissue spheroids placed on electrospun polyurethane scaffold before tissue fusion and without TGF-β1 treatment (control). Scale bar—1 mm. (b) Large holes in the fused tissue construct are formed on the pre-stretched electrospun polyurethane scaffold without TGF-β1 treatment (control). Scale bar—1 mm. (c) Tissue spheroids adherent to the electrospun polyurethane scaffold before tissue fusion and TGF-β1 treatment (experiment). Scale bar—1 mm. (d) A reduction in the size and density of holes in the fused tissue construct on pre-stretched electrospun polyurethane scaffold after TGF-β1 treatment (experiment). Scale bar—1 mm.TGF: tissue growth factor.

Mentions: Potent fibrogenic factor TGF-β1 capable of inducing extracellular matrix synthesis and deposition as well as contractile phenotype in employed human ADSCs was used to eliminate holes and mature the tissue constructs. In order to estimate the effect of TGF-β1 treatment on material properties of tissue-engineered constructs, biomechanical testing was performed using cell-free electrospun scaffolds and tissue spheroid seeded electrospun scaffolds (but without TGF treatment) and as controls. The use of TGF-β1 dramatically reduced the number and diameter of the holes (Figure 5). The number of holes reduced from 3.4 ± 0.6 to 1.9 ± 0.3 (p < 0.05), and the diameter of holes reduced from 229 ± 63 to 110 ± 24 (p < 0.05) (Figure 6). The observations revealed that after TGF-β1 treatment, the remaining tissue spheroids inside tissue-engineered constructs were more regularly packed. Moreover, the incubation with the TGF-β1 resulted in an increased maximal load and stiffness of tissue-engineered construct (Figure 7(a)). Finally, TGF-β1 was also shown to induce the synthesis of collagen type 1 and the matricellular protein periostin in the tissue-engineered construct (Figure 7(b)).


The fusion of tissue spheroids attached to pre-stretched electrospun polyurethane scaffolds.

Beachley V, Kasyanov V, Nagy-Mehesz A, Norris R, Ozolanta I, Kalejs M, Stradins P, Baptista L, da Silva K, Grainjero J, Wen X, Mironov V - J Tissue Eng (2014)

Formation of holes in tissue constructs as a result of incomplete tissue spheroids fusion on pre-stretched electrospun matrix and their dramatic reduction after TGF-β1 treatment. (a) Tissue spheroids placed on electrospun polyurethane scaffold before tissue fusion and without TGF-β1 treatment (control). Scale bar—1 mm. (b) Large holes in the fused tissue construct are formed on the pre-stretched electrospun polyurethane scaffold without TGF-β1 treatment (control). Scale bar—1 mm. (c) Tissue spheroids adherent to the electrospun polyurethane scaffold before tissue fusion and TGF-β1 treatment (experiment). Scale bar—1 mm. (d) A reduction in the size and density of holes in the fused tissue construct on pre-stretched electrospun polyurethane scaffold after TGF-β1 treatment (experiment). Scale bar—1 mm.TGF: tissue growth factor.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2 - License 3
Show All Figures
getmorefigures.php?uid=PMC4229054&req=5

fig5-2041731414556561: Formation of holes in tissue constructs as a result of incomplete tissue spheroids fusion on pre-stretched electrospun matrix and their dramatic reduction after TGF-β1 treatment. (a) Tissue spheroids placed on electrospun polyurethane scaffold before tissue fusion and without TGF-β1 treatment (control). Scale bar—1 mm. (b) Large holes in the fused tissue construct are formed on the pre-stretched electrospun polyurethane scaffold without TGF-β1 treatment (control). Scale bar—1 mm. (c) Tissue spheroids adherent to the electrospun polyurethane scaffold before tissue fusion and TGF-β1 treatment (experiment). Scale bar—1 mm. (d) A reduction in the size and density of holes in the fused tissue construct on pre-stretched electrospun polyurethane scaffold after TGF-β1 treatment (experiment). Scale bar—1 mm.TGF: tissue growth factor.
Mentions: Potent fibrogenic factor TGF-β1 capable of inducing extracellular matrix synthesis and deposition as well as contractile phenotype in employed human ADSCs was used to eliminate holes and mature the tissue constructs. In order to estimate the effect of TGF-β1 treatment on material properties of tissue-engineered constructs, biomechanical testing was performed using cell-free electrospun scaffolds and tissue spheroid seeded electrospun scaffolds (but without TGF treatment) and as controls. The use of TGF-β1 dramatically reduced the number and diameter of the holes (Figure 5). The number of holes reduced from 3.4 ± 0.6 to 1.9 ± 0.3 (p < 0.05), and the diameter of holes reduced from 229 ± 63 to 110 ± 24 (p < 0.05) (Figure 6). The observations revealed that after TGF-β1 treatment, the remaining tissue spheroids inside tissue-engineered constructs were more regularly packed. Moreover, the incubation with the TGF-β1 resulted in an increased maximal load and stiffness of tissue-engineered construct (Figure 7(a)). Finally, TGF-β1 was also shown to induce the synthesis of collagen type 1 and the matricellular protein periostin in the tissue-engineered construct (Figure 7(b)).

Bottom Line: Tissue spheroids attached, spread, and fused after being placed on pre-stretched polyurethane electrospun matrices and formed tissue constructs.Efforts to eliminate hole defects with fibrogenic tissue growth factor-β resulted in the increased synthesis of collagen and periostin and a dramatic reduction in hole size and number.In control experiments, tissue spheroids fuse on a non-adhesive hydrogel and form continuous tissue constructs without holes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Rowan University, Glassboro, NJ, USA.

ABSTRACT
Effective cell invasion into thick electrospun biomimetic scaffolds is an unsolved problem. One possible strategy to biofabricate tissue constructs of desirable thickness and material properties without the need for cell invasion is to use thin (<2 µm) porous electrospun meshes and self-assembling (capable of tissue fusion) tissue spheroids as building blocks. Pre-stretched electrospun meshes remained taut in cell culture and were able to support tissue spheroids with minimal deformation. We hypothesize that elastic electrospun scaffolds could be used as temporal support templates for rapid self-assembly of cell spheroids into higher order tissue structures, such as engineered vascular tissue. The aim of this study was to investigate how the attachment of tissue spheroids to pre-stretched polyurethane scaffolds may interfere with the tissue fusion process. Tissue spheroids attached, spread, and fused after being placed on pre-stretched polyurethane electrospun matrices and formed tissue constructs. Efforts to eliminate hole defects with fibrogenic tissue growth factor-β resulted in the increased synthesis of collagen and periostin and a dramatic reduction in hole size and number. In control experiments, tissue spheroids fuse on a non-adhesive hydrogel and form continuous tissue constructs without holes. Our data demonstrate that tissue spheroids attached to thin stretched elastic electrospun scaffolds have an interrupted tissue fusion process. The resulting tissue-engineered construct phenotype is a direct outcome of the delicate balance of the competing physical forces operating during the tissue fusion process at the interface of the pre-stretched elastic scaffold and the attached tissue spheroids. We have shown that with appropriate treatments, this process can be modulated, and thus, a thin pre-stretched elastic polyurethane electrospun scaffold could serve as a supporting template for rapid biofabrication of thick tissue-engineered constructs without the need for cell invasion.

No MeSH data available.


Related in: MedlinePlus