A simultaneous process of 3D magnesium phosphate scaffold fabrication and bioactive substance loading for hard tissue regeneration

https://doi.org/10.1016/j.msec.2013.12.007Get rights and content

Highlights

  • 3D porous MgP scaffolds were prepared by novel two step room temperature fabrication.

  • Paste extruding deposition system was applied for fabricating 3D structure of scaffold.

  • Cementation was adapted for solidification of extruded ceramic paste at room temperature.

  • Suggested process enhanced both drug loading efficiency and release performance.

  • MgP scaffold showed good pore structural conditions, mechanical property and cell affinity.

Abstract

A novel room temperature process was developed to produce a 3D porous magnesium phosphate (MgP) scaffold with high drug load/release efficiency for use in hard tissue regeneration through a combination of a paste extruding deposition (PED) system and cement chemistry. MgP scaffolds were prepared using a two-step process. The first step was fabrication of the 3D porous scaffold green body to control both the morphology and pore structure using a PED system without hardening. The second step was cementation, which was carried out by immersing the scaffold green body in the binder solution for hardening instead of the typical sintering process in ceramic scaffold fabrication. Separation of the manufacturing process and cement reaction was important to secure enough time to fabricate a 3D scaffold with various sizes and architectures under homogeneous extruding conditions. Because the whole process is carried out at room temperature, the bioactive molecules, which are easily denatured by heat, may apply to scaffolds during the process. Lysozyme was selected as a model bioactive substance to demonstrate the efficiency of this process; this was directly mixed into MgP powder to introduce homogeneous distribution in the scaffold. The extruding paste for the PED system was prepared using the MgP–lysozyme blended powder as starting materials. That is, both 3D scaffold fabrication and functionalization of the scaffold with bioactive substances could be carried out simultaneously. This process significantly enhanced both drug loading efficiency and release performance compared to the typical sintering process, where the drug is generally loaded by adsorption after heat treatment. The MgP scaffold developed in this study satisfied the required conditions for scaffolding in hard tissue regeneration in an ideal manner, including 3 dimensionally well-interconnected pore structures, favorable mechanical properties, biodegradability, good cell affinity and in vitro biocompatibility; thus, it has excellent potential for application in the field of biomaterials.

Graphical abstract

A novel room temperature process was developed to produce a 3D porous magnesium phosphate (MgP) scaffold with high drug load/release efficiency for bone tissue regeneration, using a combination of a paste extruding deposition (PED) system and cement chemistry.

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Keywords

Magnesium phosphate
Room temperature fabrication
Paste extruding deposition
Bone scaffold
Direct drug loading

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These authors contributed equally to this work.

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