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Biomimetic apatite-coated alginate/chitosan microparticles as osteogenic protein carriers

Paper ID Volume ID Publish Year Pages File Format Full-Text
9752 644 2009 8 PDF Available
Title
Biomimetic apatite-coated alginate/chitosan microparticles as osteogenic protein carriers
Abstract

Bone morphogenetic proteins (BMPs) are currently approved for spinal fusion, tibial fracture repair, and maxillofacial bone regeneration. However, BMP pleiotropism, paradoxical activities on precursor cells, and unexpected side effects at local and ectopic sites may limit their usage. Thus, the need remains for alternative osteoinductive factors that provide more bone-specific activities with fewer adverse effects. Nell-1 [Nel-like molecule-1; Nel (a protein highly expressed in neural tissue encoding epidermal growth factor like domain)] is a novel osteogenic protein believed to specifically target cells committed to the osteogenic lineage. The objective of this project is to incorporate Nell-1 into a moldable putty carrier that can adapt to bony defects and deliver Nell-1 to the local microenvironment. We show here that moldability can be achieved by mixing hyaluronan hydrogel with two types of particles: demineralized bone powder for osteoconductivity, and biomimetic apatite-coated alginate/chitosan microparticles for controlled Nell-1 delivery. Besides enhancing overall osteoconductivity of the carrier, the biomimetic apatite coating also provides a more sustained release (∼15% cumulative release over 30 days) and greatly reduces the initial burst release that is observed with non-coated alginate/chitosan microparticles (∼40% release after 1 day). The efficacy of Nell-1 delivery from these carriers was evaluated in a rat spinal fusion model against Nell-free carriers as controls. At 4 weeks post-implantation, Nell-1 enhanced spinal fusion rates as assessed by manual palpation, radiographs, high-resolution micro-computerized tomography (μCT), and histology. This moldable putty carrier system appears to be a suitable carrier for promoting osteogenesis, and will be further evaluated in larger animal models over longer periods to follow the remodeling of the regenerated bone.

Keywords
Biomimetic apatite; Alginate; Chitosan; Microparticles; Nell-1; Controlled release
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Biomimetic apatite-coated alginate/chitosan microparticles as osteogenic protein carriers
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 30, Issue 30, October 2009, Pages 6094–6101
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