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The impact of critical point drying with liquid carbon dioxide on collagen–hydroxyapatite composite scaffolds

Paper ID Volume ID Publish Year Pages File Format Full-Text
1564 86 2008 10 PDF Available
Title
The impact of critical point drying with liquid carbon dioxide on collagen–hydroxyapatite composite scaffolds
Abstract

Collagen–hydroxyapatite composites for bone tissue engineering are usually made by freezing an aqueous dispersion of these components and then freeze-drying. This method creates a foamed matrix which may not be optimum for growing cell colonies larger than a few hundred micrometres due to the limited diffusion of nutrients and oxygen, and the limited removal of waste metabolites. Incorporating a network of microchannels in the interior of the scaffold which may permit the flow of nutrient-rich media has been proposed as a method to overcome these diffusion constraints. A novel three-dimensional printing and critical point drying technique previously used to make collagen scaffolds has been modified to create collagen–hydroxyapatite scaffolds. This study investigates the properties of collagen and collagen–hydroxyapatite scaffolds and whether subjecting collagen and hydroxyapatite to critical point drying with liquid carbon dioxide results in any changes to the individual components. Specifically, the hydroxyapatite component was characterized before and after processing using wavelength-dispersive X-ray spectroscopy, X-ray diffraction and infrared spectroscopy. Critical point drying did not induce elemental, crystallographic or molecular changes in the hydroxyapatite. The quaternary structure of collagen was characterized using transmission electron microscopy and the quarter-staggered array characteristic of native collagen remained after processing. Microstructural characterization of the composites using scanning electron microscopy showed the hydroxyapatite particles were mechanically interlocked in the collagen matrix. The in vitro biological response of MG63 osteogenic cells to the composite scaffolds were characterized using the Alamar Blue™, PicoGreen™, alkaline phosphate and Live/Dead™ assays, and revealed that the critical point dried scaffolds were non-cytotoxic.

Keywords
Bone tissue engineering; Critical point drying; Supercritical carbon dioxide; Rapid prototyping; Collagen
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The impact of critical point drying with liquid carbon dioxide on collagen–hydroxyapatite composite scaffolds
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Publisher
Database: Elsevier - ScienceDirect
Journal: Acta Biomaterialia - Volume 4, Issue 5, September 2008, Pages 1322–1331
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us