Evaluation of Sustained BMP-2 Release Profiles Using a Novel Fluorescence-Based Retention Assay.

Wonmo Kang,Dong-Sung Lee,Jun-Hyeog Jang,Chih-Hsin Tang

doi:10.1371/journal.pone.0123402

Wonmo Kang, Dong-Sung Lee + Show 2 more

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https://doi.org/10.1371/journal.pone.0123402

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Journal: PloS one	Publication Date: Apr 22, 2015
Citations: 10	License type: CC BY 4.0

Affiliation: Inha University, Konkuk University

Abstract

The purpose of this study was to develop and characterize a novel fluorescence-based retention assay for the evaluation of the release profile of bone morphogenetic protein-2 (BMP-2) released from bone graft carrier. In this study, we evaluated the binding, release kinetics, and delivery efficacies of BMP-2 incorporated into hydroxyapatite (HA) bone grafts. The evaluation of the release profile of BMP-2 from HA bone grafts using a fluorescence-based retention assay revealed initial burst releases from the HA bone grafts followed by long sustained releases up to 14 weeks. The sustained biological activity of the released BMP-2 from HA bone grafts over the full 14-week period supports a long sustained mechanism via fluorescence-based retention assay. Thus, the results from this study show that BMP-2 could be incorporated into HA bone grafts for sustained release over a prolonged period of time with retention of bioactivity and our fluorescence-based retention assay, which is principally detecting the retention profile of BMP-2 in HA bone grafts, is more accurate than conventionally collecting the released BMP-2 for evaluation of BMP-2 release profiles.

Highlights

Bone morphogenetic protein-2 (BMP-2) has become the most powerful osteoinductive growth factor for bone regeneration [1]
To develop a new method to evaluate the release of BMP-2 from HA bone grafts and to assess the suitability of these HA bone grafts for bone regeneration, we constructed fluorescent BMP2 fusion protein, BMP-2GFP
After 1 week, the remaining amount of BMP-2GFP released from HA bone grafts was barely detectable, detecting 14.7% of the total loaded BMP-2GFP in HA bone grafts over 14 weeks (Fig 4)

Summary

Introduction

Bone morphogenetic protein-2 (BMP-2) has become the most powerful osteoinductive growth factor for bone regeneration [1]. Recombinant BMP-2 in combination with a collagen sponge has been approved for the treatment of open long bone fractures and combined with a metal cage for spinal fusions [2, 3]. Due to a short half-life, supraphysiological doses are applied resulting in negative side effects such as ectopic bone formation, or even loss of bone [4, 5]. Current applications include rhBMP-2 loaded in delivery systems to retain rhBMP-2 at the site of injury for a prolonged time frame with a controlled release enhancing the effect [6, 7]. Sustained release of growth factors is a highly desired property of controlled-release materials [6, 8].

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