Porous deproteinized bovine bone scaffold with three-dimensional localized drug delivery system using chitosan microspheres.

Qing Li,Yuan Xi,Tong Wang,Gang Zhou,Zhihui Tang,Xin Yu

doi:10.1186/s12938-015-0028-2

Qing Li, Yuan Xi + Show 4 more

Open Access

https://doi.org/10.1186/s12938-015-0028-2

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Abstract

BackgroundBone substation grafts, such as hydroxyapatite (HA) and tricalciumphosphate (TCP), have been extensively used in clinical applications, but evidence suggests that they offer poor osteoinductive properties compared to allografts and autografts. In order to increase bone growth with such grafts, Bone Morphogenetic Protein 2 (BMP-2) was incorporated into a three dimensional reservoir. The purpose of the present study was to develop a novel drug delivery system which is capable of controlled release of BMP-2.MethodsDBB were prepared from bovine cancellous bone harvested from fetal bovine femur or tibia and then sinting at 1000°C. BMP-2-loaded chitosan (CS) microspheres were fabricated by cross-linking. Then the treated DBB powders were blended with chitosan microspheres solution. Finally, the composites were lyophilized with a freeze dryer to obtain the DBB/CMs scaffolds. X-ray diffractor (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) were used to characterize the sample. The quantification of the delivery profile of BMP-2 was determined using an enzyme-linked immunosorbent assay (ELISA) kit. The in vitro assays were to characterize the biocompatibility of this composite.ResultsIn this study, BMP-2/Chitosan (CS) microspheres were successively loaded onto a deproteinized bovine bone (DBB) scaffold. The release profile of BMP-2 indicated an initial burst release followed by a more even sustained release. An in vitro bioactivity assay revealed that the encapsulated growth factor was biologically active.ConclusionsThe cell culture assay suggest that the excellent biocompatibility of the DBB- BMP-2/CS. Therefore, this novel microsphere scaffold system can be effectively used in current tissue engineering applications.

Highlights

Bone substation grafts, such as hydroxyapatite (HA) and tricalciumphosphate (TCP), have been extensively used in clinical applications, but evidence suggests that they offer poor osteoinductive properties compared to allografts and autografts
The deproteinized bovine bone (DBB)/chitosan microspheres (CMs) scaffold loaded with Bone Morphogenetic Protein 2 (BMP-2) showed excellent osteoinductivity
The findings of this study indicate that CMs scaffolds are degradable and both in vitro and in vivo results indicate that the coating can prevent and delay the degradation of underlying Bio-CaP, even though the coating is biodegradable

Summary

Introduction

Bone substation grafts, such as hydroxyapatite (HA) and tricalciumphosphate (TCP), have been extensively used in clinical applications, but evidence suggests that they offer poor osteoinductive properties compared to allografts and autografts. In order to increase bone growth with such grafts, Bone Morphogenetic Protein 2 (BMP-2) was incorporated into a three dimensional reservoir. Bone grafting, the gold standard in bone defect management, bears considerable risks; donor site pain and morbidity, infection, increased blood loss, and longer operating times [2,3,4]. Synthetic calcium phosphate ceramics (such as β-tricalciumphosphate (β-TCP) [6], and hydroxyapatite (HA) [7]) with their excellent biocompatibility are designed to mimic the native extracellular matrix as closely as possible [8], the porous network of the artificial bone scaffold still cannot compare to natural bone in terms of structure and function

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