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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

Cardiac Tissue-Velcro characterization.(A) Cardiac cell assembly around a mesh over 7 days. Scale bar, 100 μm. (B) Area decrease (%) during 1-Hz paced contraction derived from scaffold deformation increased from day 4 to 6 (day 4: 0.9 ± 0.3%, day 6: 1.4 ± 0.07%, mean ± SD, n = 3). Representative plots of electrically paced (1-Hz) cardiac tissue contracting and compressing the scaffold on days 4 and 6 of culture (n = 3). (C) Immunostaining of cardiac Tissue-Velcro on day 7 with sarcomeric α-actinin (red) and F-actin (green) (n = 4). Scale bar, 30 μm. (D) SEM of a Tissue-Velcro showing tissue bundles (day 7); scale bar, 100 μm. Inset, high-magnification SEM of a segment of Tissue-Velcro; scale bar, 100 μm. (E) EC coating around 7-day-old cardiac tissue grew to confluence in 24 hours (CD31, red). Scale bar, 100 μm. (F) CFDA cell tracker (green)–labeled endothelial cells; scale bar, 50 μm. (G) Representative images of nuclear staining (DAPI, blue) overlaid with nuclear orientation vectors along the long nuclear axis (n = 3). Scale bar, 50 μm. (H) Normalized distribution of orientation angles for cell nuclei and scaffold struts, respectively (representative trace of n = 3).
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Figure 3: Cardiac Tissue-Velcro characterization.(A) Cardiac cell assembly around a mesh over 7 days. Scale bar, 100 μm. (B) Area decrease (%) during 1-Hz paced contraction derived from scaffold deformation increased from day 4 to 6 (day 4: 0.9 ± 0.3%, day 6: 1.4 ± 0.07%, mean ± SD, n = 3). Representative plots of electrically paced (1-Hz) cardiac tissue contracting and compressing the scaffold on days 4 and 6 of culture (n = 3). (C) Immunostaining of cardiac Tissue-Velcro on day 7 with sarcomeric α-actinin (red) and F-actin (green) (n = 4). Scale bar, 30 μm. (D) SEM of a Tissue-Velcro showing tissue bundles (day 7); scale bar, 100 μm. Inset, high-magnification SEM of a segment of Tissue-Velcro; scale bar, 100 μm. (E) EC coating around 7-day-old cardiac tissue grew to confluence in 24 hours (CD31, red). Scale bar, 100 μm. (F) CFDA cell tracker (green)–labeled endothelial cells; scale bar, 50 μm. (G) Representative images of nuclear staining (DAPI, blue) overlaid with nuclear orientation vectors along the long nuclear axis (n = 3). Scale bar, 50 μm. (H) Normalized distribution of orientation angles for cell nuclei and scaffold struts, respectively (representative trace of n = 3).

Mentions: The fibers of the mesh provided topographical cues to guide cellular assembly in the xy plane. Neonatal rat CMs were seeded onto the scaffolds with Matrigel, where the cells initially wrapped around the struts of the mesh and then remodeled the matrix by compacting and elongating around the struts over a period of 7 days (Fig. 3A and movie S4). After 4 to 6 days, the tissues displayed spontaneous contraction (movie S5). Cardiac tissue contraction was paced using an electrical stimulator (movie S6). As the tissue contracted, it compressed the scaffold in a spring-like fashion. Scaffold autofluorescence allowed for the deformation of the scaffold mesh under fluorescence microscopy to be tracked with image processing (movie S7). The degree of scaffold compression was characterized by tracking the decrease in the honeycomb area during contraction. A trend toward higher scaffold compression (percent area decrease at each beat) was recorded at day 6 compared to day 4 (day 4: 0.87 ± 0.27%, day 6: 1.44 ± 0.07%, n = 3) (Fig. 3B). On day 8, the linear percent shortening was higher in the short-axis (yD) direction than in the long-axis (xD) direction (P = 0.038) (fig. S3), consistent with the lower modulus in the short-axis direction allowing for greater deformability (Fig. 2B). Immunofluorescence staining of the cytoskeletal actin filament F-actin and the contractile protein sarcomeric α-actinin and SEM revealed formation of a tissue layer with elongated CMs around the scaffold struts and visible cross-striations (Fig. 3, C and D, and fig. S4). Cardiac tissue was also able to exhibit a positive chronotropic response upon exposure to 300 nM epinephrine (fig. S5 and movie S11).


Platform technology for scalable assembly of instantaneously functional mosaic tissues.

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

Cardiac Tissue-Velcro characterization.(A) Cardiac cell assembly around a mesh over 7 days. Scale bar, 100 μm. (B) Area decrease (%) during 1-Hz paced contraction derived from scaffold deformation increased from day 4 to 6 (day 4: 0.9 ± 0.3%, day 6: 1.4 ± 0.07%, mean ± SD, n = 3). Representative plots of electrically paced (1-Hz) cardiac tissue contracting and compressing the scaffold on days 4 and 6 of culture (n = 3). (C) Immunostaining of cardiac Tissue-Velcro on day 7 with sarcomeric α-actinin (red) and F-actin (green) (n = 4). Scale bar, 30 μm. (D) SEM of a Tissue-Velcro showing tissue bundles (day 7); scale bar, 100 μm. Inset, high-magnification SEM of a segment of Tissue-Velcro; scale bar, 100 μm. (E) EC coating around 7-day-old cardiac tissue grew to confluence in 24 hours (CD31, red). Scale bar, 100 μm. (F) CFDA cell tracker (green)–labeled endothelial cells; scale bar, 50 μm. (G) Representative images of nuclear staining (DAPI, blue) overlaid with nuclear orientation vectors along the long nuclear axis (n = 3). Scale bar, 50 μm. (H) Normalized distribution of orientation angles for cell nuclei and scaffold struts, respectively (representative trace of n = 3).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Cardiac Tissue-Velcro characterization.(A) Cardiac cell assembly around a mesh over 7 days. Scale bar, 100 μm. (B) Area decrease (%) during 1-Hz paced contraction derived from scaffold deformation increased from day 4 to 6 (day 4: 0.9 ± 0.3%, day 6: 1.4 ± 0.07%, mean ± SD, n = 3). Representative plots of electrically paced (1-Hz) cardiac tissue contracting and compressing the scaffold on days 4 and 6 of culture (n = 3). (C) Immunostaining of cardiac Tissue-Velcro on day 7 with sarcomeric α-actinin (red) and F-actin (green) (n = 4). Scale bar, 30 μm. (D) SEM of a Tissue-Velcro showing tissue bundles (day 7); scale bar, 100 μm. Inset, high-magnification SEM of a segment of Tissue-Velcro; scale bar, 100 μm. (E) EC coating around 7-day-old cardiac tissue grew to confluence in 24 hours (CD31, red). Scale bar, 100 μm. (F) CFDA cell tracker (green)–labeled endothelial cells; scale bar, 50 μm. (G) Representative images of nuclear staining (DAPI, blue) overlaid with nuclear orientation vectors along the long nuclear axis (n = 3). Scale bar, 50 μm. (H) Normalized distribution of orientation angles for cell nuclei and scaffold struts, respectively (representative trace of n = 3).
Mentions: The fibers of the mesh provided topographical cues to guide cellular assembly in the xy plane. Neonatal rat CMs were seeded onto the scaffolds with Matrigel, where the cells initially wrapped around the struts of the mesh and then remodeled the matrix by compacting and elongating around the struts over a period of 7 days (Fig. 3A and movie S4). After 4 to 6 days, the tissues displayed spontaneous contraction (movie S5). Cardiac tissue contraction was paced using an electrical stimulator (movie S6). As the tissue contracted, it compressed the scaffold in a spring-like fashion. Scaffold autofluorescence allowed for the deformation of the scaffold mesh under fluorescence microscopy to be tracked with image processing (movie S7). The degree of scaffold compression was characterized by tracking the decrease in the honeycomb area during contraction. A trend toward higher scaffold compression (percent area decrease at each beat) was recorded at day 6 compared to day 4 (day 4: 0.87 ± 0.27%, day 6: 1.44 ± 0.07%, n = 3) (Fig. 3B). On day 8, the linear percent shortening was higher in the short-axis (yD) direction than in the long-axis (xD) direction (P = 0.038) (fig. S3), consistent with the lower modulus in the short-axis direction allowing for greater deformability (Fig. 2B). Immunofluorescence staining of the cytoskeletal actin filament F-actin and the contractile protein sarcomeric α-actinin and SEM revealed formation of a tissue layer with elongated CMs around the scaffold struts and visible cross-striations (Fig. 3, C and D, and fig. S4). Cardiac tissue was also able to exhibit a positive chronotropic response upon exposure to 300 nM epinephrine (fig. S5 and movie S11).

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