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A Structurally and Functionally Biomimetic Biphasic Scaffold for Intervertebral Disc Tissue Engineering.

Choy AT, Chan BP - PLoS ONE (2015)

Bottom Line: On mechanical testing, the height of our engineered disc recovered by ~82-89% in an annulus-independent manner, when compared with the 99% recovery exhibited by native disc.Biphasic scaffolds comprised of 10 annulus fibrosus-like lamellae had the best overall mechanical performance among the various designs owing to their similarity to native disc in most aspects, including elastic compliance during creep and recovery, and viscous compliance during recovery.However, the dynamic mechanical performance (including dynamic stiffness and damping factor) of all the biphasic scaffolds was similar to that of the native discs.

View Article: PubMed Central - PubMed

Affiliation: Tissue Engineering Laboratory, Department of Mechanical Engineering, The University of Hong Kong, Hong Kong Special Administrative Region, China.

ABSTRACT
Tissue engineering offers high hopes for the treatment of intervertebral disc (IVD) degeneration. Whereas scaffolds of the disc nucleus and annulus have been extensively studied, a truly biomimetic and mechanically functional biphasic scaffold using naturally occurring extracellular matrix is yet to be developed. Here, a biphasic scaffold was fabricated with collagen and glycosaminoglycans (GAGs), two of the most abundant extracellular matrix components in the IVD. Following fabrication, the scaffold was characterized and benchmarked against native disc. The biphasic scaffold was composed of a collagen-GAG co-precipitate making up the nucleus pulposus-like core, and this was encapsulated in multiple lamellae of photochemically crosslinked collagen membranes comprising the annulus fibrosus-like lamellae. On mechanical testing, the height of our engineered disc recovered by ~82-89% in an annulus-independent manner, when compared with the 99% recovery exhibited by native disc. The annulus-independent nature of disc height recovery suggests that the fluid replacement function of the engineered nucleus pulposus core might mimic this hitherto unique feature of native disc. Biphasic scaffolds comprised of 10 annulus fibrosus-like lamellae had the best overall mechanical performance among the various designs owing to their similarity to native disc in most aspects, including elastic compliance during creep and recovery, and viscous compliance during recovery. However, the dynamic mechanical performance (including dynamic stiffness and damping factor) of all the biphasic scaffolds was similar to that of the native discs. This study contributes to the rationalized design and development of a biomimetic and mechanically viable biphasic scaffold for IVD tissue engineering.

No MeSH data available.


Related in: MedlinePlus

Dynamic stiffness and damping factor of samples during the dynamic mechanical analysis (DMA).(A) Line chart of the dynamic stiffness against the log loading frequency. (B) Bar chart showing the slope values measured for the dynamic stiffness-log loading frequency curves (mean+-2SE, n = 2–4). (C) Line charts of the damping factor (tangent delta) against log loading frequency; D: Bar chart showing the slopes of the tangent delta-log loading frequency curves (mean+-2SE, n = 2–4).
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pone.0131827.g006: Dynamic stiffness and damping factor of samples during the dynamic mechanical analysis (DMA).(A) Line chart of the dynamic stiffness against the log loading frequency. (B) Bar chart showing the slope values measured for the dynamic stiffness-log loading frequency curves (mean+-2SE, n = 2–4). (C) Line charts of the damping factor (tangent delta) against log loading frequency; D: Bar chart showing the slopes of the tangent delta-log loading frequency curves (mean+-2SE, n = 2–4).

Mentions: Fig 6 shows the changes in dynamic stiffness (K*) and the damping factor (tan delta) of samples at different loading frequencies using a log scale during DMA. Linear regression analyses showed that apart from a few exceptions in the 1-layer and 2-layer groups, all the groups showed a significant linear relationship (Fig 6A) between the dynamic stiffness and log loading frequency (at p< = 0.032). Although the overall values measured for the 10-layer group were higher than other groups, the slopes of the K*-log frequency curves (Fig 6B) were similar among all the groups including the native disc (one-way ANOVA, p = 0.149). Similarly, linear regression analyses showed that apart from a few exceptions in the 1-layer group, all the groups showed a significant linear relationship (Fig 6C) between the damping factor and log loading frequency (at p< = 0.05). The slopes of the tangent delta-log frequency curves (Fig 6D) were not significantly different among different groups (one-way ANOVA, p = 0.133) although Dunnett’s post-hoc test showed a significant difference between the native disc and the 10-layer group (p = 0.031).


A Structurally and Functionally Biomimetic Biphasic Scaffold for Intervertebral Disc Tissue Engineering.

Choy AT, Chan BP - PLoS ONE (2015)

Dynamic stiffness and damping factor of samples during the dynamic mechanical analysis (DMA).(A) Line chart of the dynamic stiffness against the log loading frequency. (B) Bar chart showing the slope values measured for the dynamic stiffness-log loading frequency curves (mean+-2SE, n = 2–4). (C) Line charts of the damping factor (tangent delta) against log loading frequency; D: Bar chart showing the slopes of the tangent delta-log loading frequency curves (mean+-2SE, n = 2–4).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4482706&req=5

pone.0131827.g006: Dynamic stiffness and damping factor of samples during the dynamic mechanical analysis (DMA).(A) Line chart of the dynamic stiffness against the log loading frequency. (B) Bar chart showing the slope values measured for the dynamic stiffness-log loading frequency curves (mean+-2SE, n = 2–4). (C) Line charts of the damping factor (tangent delta) against log loading frequency; D: Bar chart showing the slopes of the tangent delta-log loading frequency curves (mean+-2SE, n = 2–4).
Mentions: Fig 6 shows the changes in dynamic stiffness (K*) and the damping factor (tan delta) of samples at different loading frequencies using a log scale during DMA. Linear regression analyses showed that apart from a few exceptions in the 1-layer and 2-layer groups, all the groups showed a significant linear relationship (Fig 6A) between the dynamic stiffness and log loading frequency (at p< = 0.032). Although the overall values measured for the 10-layer group were higher than other groups, the slopes of the K*-log frequency curves (Fig 6B) were similar among all the groups including the native disc (one-way ANOVA, p = 0.149). Similarly, linear regression analyses showed that apart from a few exceptions in the 1-layer group, all the groups showed a significant linear relationship (Fig 6C) between the damping factor and log loading frequency (at p< = 0.05). The slopes of the tangent delta-log frequency curves (Fig 6D) were not significantly different among different groups (one-way ANOVA, p = 0.133) although Dunnett’s post-hoc test showed a significant difference between the native disc and the 10-layer group (p = 0.031).

Bottom Line: On mechanical testing, the height of our engineered disc recovered by ~82-89% in an annulus-independent manner, when compared with the 99% recovery exhibited by native disc.Biphasic scaffolds comprised of 10 annulus fibrosus-like lamellae had the best overall mechanical performance among the various designs owing to their similarity to native disc in most aspects, including elastic compliance during creep and recovery, and viscous compliance during recovery.However, the dynamic mechanical performance (including dynamic stiffness and damping factor) of all the biphasic scaffolds was similar to that of the native discs.

View Article: PubMed Central - PubMed

Affiliation: Tissue Engineering Laboratory, Department of Mechanical Engineering, The University of Hong Kong, Hong Kong Special Administrative Region, China.

ABSTRACT
Tissue engineering offers high hopes for the treatment of intervertebral disc (IVD) degeneration. Whereas scaffolds of the disc nucleus and annulus have been extensively studied, a truly biomimetic and mechanically functional biphasic scaffold using naturally occurring extracellular matrix is yet to be developed. Here, a biphasic scaffold was fabricated with collagen and glycosaminoglycans (GAGs), two of the most abundant extracellular matrix components in the IVD. Following fabrication, the scaffold was characterized and benchmarked against native disc. The biphasic scaffold was composed of a collagen-GAG co-precipitate making up the nucleus pulposus-like core, and this was encapsulated in multiple lamellae of photochemically crosslinked collagen membranes comprising the annulus fibrosus-like lamellae. On mechanical testing, the height of our engineered disc recovered by ~82-89% in an annulus-independent manner, when compared with the 99% recovery exhibited by native disc. The annulus-independent nature of disc height recovery suggests that the fluid replacement function of the engineered nucleus pulposus core might mimic this hitherto unique feature of native disc. Biphasic scaffolds comprised of 10 annulus fibrosus-like lamellae had the best overall mechanical performance among the various designs owing to their similarity to native disc in most aspects, including elastic compliance during creep and recovery, and viscous compliance during recovery. However, the dynamic mechanical performance (including dynamic stiffness and damping factor) of all the biphasic scaffolds was similar to that of the native discs. This study contributes to the rationalized design and development of a biomimetic and mechanically viable biphasic scaffold for IVD tissue engineering.

No MeSH data available.


Related in: MedlinePlus