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Platform technology for scalable assembly of instantaneously functional mosaic tissues.

Zhang B, Montgomery M, Davenport-Huyer L, Korolj A, Radisic M - Sci Adv (2015)

Bottom Line: We invented Tissue-Velcro, a bio-scaffold with a microfabricated hook and loop system.The assembled cardiac 3D tissue constructs were immediately functional as measured by their ability to contract in response to electrical field stimulation.Facile, on-demand tissue disassembly was demonstrated while preserving the structure, physical integrity, and beating function of individual layers.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada. ; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada.

ABSTRACT
Engineering mature tissues requires a guided assembly of cells into organized three-dimensional (3D) structures with multiple cell types. Guidance is usually achieved by microtopographical scaffold cues or by cell-gel compaction. The assembly of individual units into functional 3D tissues is often time-consuming, relying on cell ingrowth and matrix remodeling, whereas disassembly requires an invasive method that includes either matrix dissolution or mechanical cutting. We invented Tissue-Velcro, a bio-scaffold with a microfabricated hook and loop system. The assembly of Tissue-Velcro preserved the guided cell alignment realized by the topographical features in the 2D scaffold mesh and allowed for the instant establishment of coculture conditions by spatially defined stacking of cardiac cell layers or through endothelial cell coating. The assembled cardiac 3D tissue constructs were immediately functional as measured by their ability to contract in response to electrical field stimulation. Facile, on-demand tissue disassembly was demonstrated while preserving the structure, physical integrity, and beating function of individual layers.

No MeSH data available.


Related in: MedlinePlus

Tissue function and viability upon assembly and disassembly.(A) Coculture conditions were instantaneously established in the z direction by assembling two layers of Tissue-Velcro (day 7): one consisting of cardiac FBs (red) and the second consisting of CMs (green). Scale bar, 800 μm. Tissue interlocking was visualized with high-magnification fluorescent images focusing on layer 1 (L1) and layer 2 (L2). Scale bar, 200 μm. (B) Assembly into a three-layer CM tissue construct. Scale bar, 800 μm. High-magnification fluorescent images focused on L1 and L3 confirm Tissue-Velcro interlocking. Scale bar, 200 μm. Arrowheads point to T-shaped microhooks protruding from the middle layer (L2) into the top layer (L1). (C) Electrical excitability parameters of the cardiac Tissue-Velcro (day 7) before assembly (mean ± SD, n = 8), after assembly (two-layer, mean ± SD, n = 4), after disassembly (mean ± SD, n = 8), and 1 day after disassembly (mean ± SD, n = 8). (D and E) Viability staining of CM Tissue-Velcro (day 4) (D) before (n = 3) and (E) after the tissue assembly/disassembly process (n = 4). Scale bar, 200 μm. CFDA, green; propidium iodide (PI), red. Scaffold struts exhibit autofluorescence in the red channel. (F) Quantification of tissue viability from LDH activity in tissue culture media collected before (mean ± SD, n = 8) and after the tissue assembly/disassembly process (mean ± SD, n = 4).
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Figure 4: Tissue function and viability upon assembly and disassembly.(A) Coculture conditions were instantaneously established in the z direction by assembling two layers of Tissue-Velcro (day 7): one consisting of cardiac FBs (red) and the second consisting of CMs (green). Scale bar, 800 μm. Tissue interlocking was visualized with high-magnification fluorescent images focusing on layer 1 (L1) and layer 2 (L2). Scale bar, 200 μm. (B) Assembly into a three-layer CM tissue construct. Scale bar, 800 μm. High-magnification fluorescent images focused on L1 and L3 confirm Tissue-Velcro interlocking. Scale bar, 200 μm. Arrowheads point to T-shaped microhooks protruding from the middle layer (L2) into the top layer (L1). (C) Electrical excitability parameters of the cardiac Tissue-Velcro (day 7) before assembly (mean ± SD, n = 8), after assembly (two-layer, mean ± SD, n = 4), after disassembly (mean ± SD, n = 8), and 1 day after disassembly (mean ± SD, n = 8). (D and E) Viability staining of CM Tissue-Velcro (day 4) (D) before (n = 3) and (E) after the tissue assembly/disassembly process (n = 4). Scale bar, 200 μm. CFDA, green; propidium iodide (PI), red. Scaffold struts exhibit autofluorescence in the red channel. (F) Quantification of tissue viability from LDH activity in tissue culture media collected before (mean ± SD, n = 8) and after the tissue assembly/disassembly process (mean ± SD, n = 4).

Mentions: Individual tissues cultured in parallel were assembled simply by overlapping multiple tissues one on top of the other, allowing the hooks from one scaffold to grab onto the struts of the other scaffold (Fig. 4). This interlocking mechanism was achieved by a gentle compression of the two tissues together. Once affixed in place, each tissue could be separated by specifically peeling one off another; handling or manipulating the entire multilayer tissue did not disassemble the individual layers (movie S3). During assembly, different cell types cultured on different scaffold meshes were positioned strategically to stack the tissues in the z axis. To demonstrate this, we labeled rat cardiac FBs and rat CMs red and green, respectively, and affixed the layers together, instantaneously establishing coculture conditions (Fig. 4A). The two-layer stack had a thickness of 580 ± 5 μm, which was derived from the scaffold dimensions and based on the overlap configuration of two Tissue-Velcro scaffolds. Additionally, three cardiac tissue meshes labeled with two different fluorescent cell trackers were locked into one tissue construct (Fig. 4B and movie S8). The three-layer stack had a thickness of 712 ± 7 μm. High-magnification images show the hooks from the red tissue mesh penetrated through and locked onto the struts of the green tissue mesh on top (Fig. 4B).


Platform technology for scalable assembly of instantaneously functional mosaic tissues.

Zhang B, Montgomery M, Davenport-Huyer L, Korolj A, Radisic M - Sci Adv (2015)

Tissue function and viability upon assembly and disassembly.(A) Coculture conditions were instantaneously established in the z direction by assembling two layers of Tissue-Velcro (day 7): one consisting of cardiac FBs (red) and the second consisting of CMs (green). Scale bar, 800 μm. Tissue interlocking was visualized with high-magnification fluorescent images focusing on layer 1 (L1) and layer 2 (L2). Scale bar, 200 μm. (B) Assembly into a three-layer CM tissue construct. Scale bar, 800 μm. High-magnification fluorescent images focused on L1 and L3 confirm Tissue-Velcro interlocking. Scale bar, 200 μm. Arrowheads point to T-shaped microhooks protruding from the middle layer (L2) into the top layer (L1). (C) Electrical excitability parameters of the cardiac Tissue-Velcro (day 7) before assembly (mean ± SD, n = 8), after assembly (two-layer, mean ± SD, n = 4), after disassembly (mean ± SD, n = 8), and 1 day after disassembly (mean ± SD, n = 8). (D and E) Viability staining of CM Tissue-Velcro (day 4) (D) before (n = 3) and (E) after the tissue assembly/disassembly process (n = 4). Scale bar, 200 μm. CFDA, green; propidium iodide (PI), red. Scaffold struts exhibit autofluorescence in the red channel. (F) Quantification of tissue viability from LDH activity in tissue culture media collected before (mean ± SD, n = 8) and after the tissue assembly/disassembly process (mean ± SD, n = 4).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4643798&req=5

Figure 4: Tissue function and viability upon assembly and disassembly.(A) Coculture conditions were instantaneously established in the z direction by assembling two layers of Tissue-Velcro (day 7): one consisting of cardiac FBs (red) and the second consisting of CMs (green). Scale bar, 800 μm. Tissue interlocking was visualized with high-magnification fluorescent images focusing on layer 1 (L1) and layer 2 (L2). Scale bar, 200 μm. (B) Assembly into a three-layer CM tissue construct. Scale bar, 800 μm. High-magnification fluorescent images focused on L1 and L3 confirm Tissue-Velcro interlocking. Scale bar, 200 μm. Arrowheads point to T-shaped microhooks protruding from the middle layer (L2) into the top layer (L1). (C) Electrical excitability parameters of the cardiac Tissue-Velcro (day 7) before assembly (mean ± SD, n = 8), after assembly (two-layer, mean ± SD, n = 4), after disassembly (mean ± SD, n = 8), and 1 day after disassembly (mean ± SD, n = 8). (D and E) Viability staining of CM Tissue-Velcro (day 4) (D) before (n = 3) and (E) after the tissue assembly/disassembly process (n = 4). Scale bar, 200 μm. CFDA, green; propidium iodide (PI), red. Scaffold struts exhibit autofluorescence in the red channel. (F) Quantification of tissue viability from LDH activity in tissue culture media collected before (mean ± SD, n = 8) and after the tissue assembly/disassembly process (mean ± SD, n = 4).
Mentions: Individual tissues cultured in parallel were assembled simply by overlapping multiple tissues one on top of the other, allowing the hooks from one scaffold to grab onto the struts of the other scaffold (Fig. 4). This interlocking mechanism was achieved by a gentle compression of the two tissues together. Once affixed in place, each tissue could be separated by specifically peeling one off another; handling or manipulating the entire multilayer tissue did not disassemble the individual layers (movie S3). During assembly, different cell types cultured on different scaffold meshes were positioned strategically to stack the tissues in the z axis. To demonstrate this, we labeled rat cardiac FBs and rat CMs red and green, respectively, and affixed the layers together, instantaneously establishing coculture conditions (Fig. 4A). The two-layer stack had a thickness of 580 ± 5 μm, which was derived from the scaffold dimensions and based on the overlap configuration of two Tissue-Velcro scaffolds. Additionally, three cardiac tissue meshes labeled with two different fluorescent cell trackers were locked into one tissue construct (Fig. 4B and movie S8). The three-layer stack had a thickness of 712 ± 7 μm. High-magnification images show the hooks from the red tissue mesh penetrated through and locked onto the struts of the green tissue mesh on top (Fig. 4B).

Bottom Line: We invented Tissue-Velcro, a bio-scaffold with a microfabricated hook and loop system.The assembled cardiac 3D tissue constructs were immediately functional as measured by their ability to contract in response to electrical field stimulation.Facile, on-demand tissue disassembly was demonstrated while preserving the structure, physical integrity, and beating function of individual layers.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada. ; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada.

ABSTRACT
Engineering mature tissues requires a guided assembly of cells into organized three-dimensional (3D) structures with multiple cell types. Guidance is usually achieved by microtopographical scaffold cues or by cell-gel compaction. The assembly of individual units into functional 3D tissues is often time-consuming, relying on cell ingrowth and matrix remodeling, whereas disassembly requires an invasive method that includes either matrix dissolution or mechanical cutting. We invented Tissue-Velcro, a bio-scaffold with a microfabricated hook and loop system. The assembly of Tissue-Velcro preserved the guided cell alignment realized by the topographical features in the 2D scaffold mesh and allowed for the instant establishment of coculture conditions by spatially defined stacking of cardiac cell layers or through endothelial cell coating. The assembled cardiac 3D tissue constructs were immediately functional as measured by their ability to contract in response to electrical field stimulation. Facile, on-demand tissue disassembly was demonstrated while preserving the structure, physical integrity, and beating function of individual layers.

No MeSH data available.


Related in: MedlinePlus