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Roofed grooves: rapid layer engineering of perfusion channels in collagen tissue models.

Tan NS, Alekseeva T, Brown RA - J Biomater Appl (2014)

Bottom Line: In the second part, this was used for effective fabrication of multi-layered plastically compressed collagen constructs with internal channels by roofing the grooves with a second layer.Resulting µ-channels retained their dimensions and were stable over time in culture with fibroblasts and could be cell seeded with a lining layer by simple transfer of epithelial cells.The results of this study provide a valuable platform for rapid fabrication of complex collagen-based tissues in particular for provision of perfusing microchannels through the bulk material for improved core nutrient supply.

View Article: PubMed Central - PubMed

Affiliation: Tissue Repair & Engineering Centre, Institute of Orthopaedics, University College London, United Kingdom.

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Collagen constructs (Sirius Red staining), showing the collagen deposition patterns around micro-moulded features within the FLS: (a) round cross-section groove, and (b) a construct embossed with a rectangular groove. In both cases the arrows indicate direction of hypothetical fluid flow, around the obstructing template at the FLS, during early compression. In both shapes the asterisk indicates the actual position of maximum collagen fibril deposition – associated with a predicted point where there will be a split in the fluid flow.
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fig8-0885328214538865: Collagen constructs (Sirius Red staining), showing the collagen deposition patterns around micro-moulded features within the FLS: (a) round cross-section groove, and (b) a construct embossed with a rectangular groove. In both cases the arrows indicate direction of hypothetical fluid flow, around the obstructing template at the FLS, during early compression. In both shapes the asterisk indicates the actual position of maximum collagen fibril deposition – associated with a predicted point where there will be a split in the fluid flow.

Mentions: Using micro-densitometry analysis of collagen, deposited around embossing templates it was possible to identify specific differences associated with altered patterns of fluid outflow. We suggest that the mechanism of formation of these patterns may be explained, at least in part, by local splitting (bifurcation) of fluid flow as it is forced to go around the template (Figure 8). During PC, fluid flows, from the bottom of the gel, up and out into the absorbent plunger, but it seems likely that mobile collagen fibrils will be deposited at points where flow bifurcates around the non-permeable template. This would most likely be the case at the early stages of compression where the FLS is first forming and fibrils are most likely to be moved. Figure 8 illustrates this idea, suggesting why round cross-section templates have a single central density peak, whilst rectangular sections have densities at each corner. The same fluid flow pattern, across the axis of the template bar, would also explain the perpendicular ridges of aligned collagen in the floor of rectangular templates.Figure 8.


Roofed grooves: rapid layer engineering of perfusion channels in collagen tissue models.

Tan NS, Alekseeva T, Brown RA - J Biomater Appl (2014)

Collagen constructs (Sirius Red staining), showing the collagen deposition patterns around micro-moulded features within the FLS: (a) round cross-section groove, and (b) a construct embossed with a rectangular groove. In both cases the arrows indicate direction of hypothetical fluid flow, around the obstructing template at the FLS, during early compression. In both shapes the asterisk indicates the actual position of maximum collagen fibril deposition – associated with a predicted point where there will be a split in the fluid flow.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2 - License 3
Show All Figures
getmorefigures.php?uid=PMC4230962&req=5

fig8-0885328214538865: Collagen constructs (Sirius Red staining), showing the collagen deposition patterns around micro-moulded features within the FLS: (a) round cross-section groove, and (b) a construct embossed with a rectangular groove. In both cases the arrows indicate direction of hypothetical fluid flow, around the obstructing template at the FLS, during early compression. In both shapes the asterisk indicates the actual position of maximum collagen fibril deposition – associated with a predicted point where there will be a split in the fluid flow.
Mentions: Using micro-densitometry analysis of collagen, deposited around embossing templates it was possible to identify specific differences associated with altered patterns of fluid outflow. We suggest that the mechanism of formation of these patterns may be explained, at least in part, by local splitting (bifurcation) of fluid flow as it is forced to go around the template (Figure 8). During PC, fluid flows, from the bottom of the gel, up and out into the absorbent plunger, but it seems likely that mobile collagen fibrils will be deposited at points where flow bifurcates around the non-permeable template. This would most likely be the case at the early stages of compression where the FLS is first forming and fibrils are most likely to be moved. Figure 8 illustrates this idea, suggesting why round cross-section templates have a single central density peak, whilst rectangular sections have densities at each corner. The same fluid flow pattern, across the axis of the template bar, would also explain the perpendicular ridges of aligned collagen in the floor of rectangular templates.Figure 8.

Bottom Line: In the second part, this was used for effective fabrication of multi-layered plastically compressed collagen constructs with internal channels by roofing the grooves with a second layer.Resulting µ-channels retained their dimensions and were stable over time in culture with fibroblasts and could be cell seeded with a lining layer by simple transfer of epithelial cells.The results of this study provide a valuable platform for rapid fabrication of complex collagen-based tissues in particular for provision of perfusing microchannels through the bulk material for improved core nutrient supply.

View Article: PubMed Central - PubMed

Affiliation: Tissue Repair & Engineering Centre, Institute of Orthopaedics, University College London, United Kingdom.

Show MeSH