DOS BULLETIN - Dansk Ortopædisk Selskab

2010-378_DOS nr. 3 2010 29/09/10 10:08 Side 108
Development of a Structurally Graded Polycaprolactone
Scaffold for Hyaline Cartilage Repair
Bjørn B. Christensen, Casper B. Foldager, Asger Kristiansen,
Jens Nygaard, Cody Bünger, Martin Lind
Orthopeadic Research Laboratory, Aarhus Sygehus; iNano,
Aarhus University; Sports- and Trauma clinic, Aarhus Sygehus
Background: This study was at pilot study for an ongoing in vivo study.
We needed to determine the optimal dioxane-water ratio and molecular
weight, of the structurally graded scaffolds, before moving on the animal
experiments.
Purpose: Rapid prototyping is a very precise scaffold manufacturing
technique where scaffolds can be constructed from MRI or CT scans to
fit into the individual tissue defects. The aim of this study is to develop
a novel Structurally Graded Poly-Capro-Lactone scaffold using rapid
prototyping for cartilage tissue engineering.
Methods: A novel SG-PCL scaffold was constructed using rapid prototyping
?(Ø 4 mm, height 2 mm). PCL fibers (MW 50 kDa) with a diameter
of 120 m were plotted producing a 3-dimensional web. The scaffold
was subsequently submerged into a mixture of dioxane, PCL and water,
and lyophilized at -32°C, creating an extremely porous graded structure.
By shifting the water-dioxane ratio, 16 batches of scaffolds with different
pore sizes were made. Using scanning electron microscopy, two scaffolds
were selected, based on porous structure. The two scaffolds were
then constructed with a graded structure of 25 and 50 kDa, giving a total
of four different scaffolds (#1-4). They were cultured with human chondrocytes
and the viability was analyzed using confocal microscopy after
1, 3 and 6 days. The scaffolds were rated based on cell migration, cell
shape and distribution of viable cells.
Findings: The scaffolds contained macro-, micro-, and nano-pores. A
large difference in investigated parameters was observed and Scaffold #3
with a water-dioxane ratio of 0.0415 provided the most viable environment
for chondrocytes according to the above-mentioned criteria. This
scaffold consisted of PCL fibers of 50 kDa and lyophilized PCL of 25
kDa.
Conclusion: We successfully constructed a SG-PCL scaffold that can be
used in future in vivo experiments, and has the potential of subsequent
functionalization with nanoparticles and growth- and differentiation factors.
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