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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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(a) Bar chart showing depth of the grooves as a percentage of expected value (depth of the rectangular cross-section templates). Seventy-five micrometres depth was taken as a 100%. Grooves were micro-moulded into the 10.6 mm deep collagen gels using templates with rungs of 25, 50 and 100 μm width. Bar charts comparing groove versus channel dimensions (depth and width), for 10.6 mm deep freshly cast collagen gels, for templates of (b) 100 × 75 μm, (c) 50 × 75 μm, (d) 25 × 75 μm template. Note the good width fidelity and depth infidelity. All dimensions were similar in both the initial grooves and the channels after they had been roofed with a second layer, indicating the stability of the grooves to the second compression.
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fig6-0885328214538865: (a) Bar chart showing depth of the grooves as a percentage of expected value (depth of the rectangular cross-section templates). Seventy-five micrometres depth was taken as a 100%. Grooves were micro-moulded into the 10.6 mm deep collagen gels using templates with rungs of 25, 50 and 100 μm width. Bar charts comparing groove versus channel dimensions (depth and width), for 10.6 mm deep freshly cast collagen gels, for templates of (b) 100 × 75 μm, (c) 50 × 75 μm, (d) 25 × 75 μm template. Note the good width fidelity and depth infidelity. All dimensions were similar in both the initial grooves and the channels after they had been roofed with a second layer, indicating the stability of the grooves to the second compression.

Mentions: Figure 6 provides an analysis and comparison of groove and channel shape. Firstly, this illustrates the degree of depth fidelity of grooves made at the three widths of rectangular cross-section template. Bars of 25 and 50 µm produced around 50% of the expected depth whilst 100 µm wide bars gave slightly better fidelity, at 60%. It is important to note, however, that this groove depth was both useful and reproducible, at a predictable proportion of the template dimension. Figure 6(b) to (d) compares the width-to-depth dimensions of both micro-moulded grooves and the roofed channels which were then produced. It is clear from this that the ratio of depth to width which characterised initial grooves from each of the test templates was exactly retained once the groove was roofed into a channel. In other words, the addition of a second gel layer with subsequent compression did not fill in or deform the features significantly. Both of these would have been possible, either blocking the grooves (and so channels) with liquid collagen solution or distorting them under subsequent compression.Figure 6.


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

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

(a) Bar chart showing depth of the grooves as a percentage of expected value (depth of the rectangular cross-section templates). Seventy-five micrometres depth was taken as a 100%. Grooves were micro-moulded into the 10.6 mm deep collagen gels using templates with rungs of 25, 50 and 100 μm width. Bar charts comparing groove versus channel dimensions (depth and width), for 10.6 mm deep freshly cast collagen gels, for templates of (b) 100 × 75 μm, (c) 50 × 75 μm, (d) 25 × 75 μm template. Note the good width fidelity and depth infidelity. All dimensions were similar in both the initial grooves and the channels after they had been roofed with a second layer, indicating the stability of the grooves to the second compression.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig6-0885328214538865: (a) Bar chart showing depth of the grooves as a percentage of expected value (depth of the rectangular cross-section templates). Seventy-five micrometres depth was taken as a 100%. Grooves were micro-moulded into the 10.6 mm deep collagen gels using templates with rungs of 25, 50 and 100 μm width. Bar charts comparing groove versus channel dimensions (depth and width), for 10.6 mm deep freshly cast collagen gels, for templates of (b) 100 × 75 μm, (c) 50 × 75 μm, (d) 25 × 75 μm template. Note the good width fidelity and depth infidelity. All dimensions were similar in both the initial grooves and the channels after they had been roofed with a second layer, indicating the stability of the grooves to the second compression.
Mentions: Figure 6 provides an analysis and comparison of groove and channel shape. Firstly, this illustrates the degree of depth fidelity of grooves made at the three widths of rectangular cross-section template. Bars of 25 and 50 µm produced around 50% of the expected depth whilst 100 µm wide bars gave slightly better fidelity, at 60%. It is important to note, however, that this groove depth was both useful and reproducible, at a predictable proportion of the template dimension. Figure 6(b) to (d) compares the width-to-depth dimensions of both micro-moulded grooves and the roofed channels which were then produced. It is clear from this that the ratio of depth to width which characterised initial grooves from each of the test templates was exactly retained once the groove was roofed into a channel. In other words, the addition of a second gel layer with subsequent compression did not fill in or deform the features significantly. Both of these would have been possible, either blocking the grooves (and so channels) with liquid collagen solution or distorting them under subsequent compression.Figure 6.

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