Fabrication of calcium phosphate 3D scaffolds for bone repair using magnetic levitational assembly

Vladislav A Parfenov,Igor V Vakhrushev,Timur Aydemir,Yury V Zobkov,Vladimir S Komlev,Yusef D Khesuani,Igor V Smirnov,Alisa A Krokhmal,Pavel A Karalkin,Stanislav V Petrov,Utkan Demirci,Frederico Das Pereira,Alexander Yu Fedotov,Vladimir A Mironov,Elizaveta V Koudan,Elizaveta K Nezhurina

doi:10.1038/s41598-020-61066-3

Abstract

The calcium phosphate particles can be used as building blocks for fabrication of 3D scaffolds intended for bone tissue engineering. This work presents for the first time a rapid creation of 3D scaffolds using magnetic levitation of calcium phosphate particles. Namely, tricalcium phosphate particles of equal size and certain porosity are used, which undergo the process of recrystallization after magnetic levitational assembly of the scaffold to ensure stitching of the scaffold. Label-free levitational assembly is achieved by using a custom-designed magnetic system in the presence of gadolinium salts, which allows the levitation of calcium phosphate particles. Chemical transformation of tricalcium- to octacalcium phosphate under the condition of magnetic levitation in non-homogeneous magnetic field is also demonstrated. This approach allows obtaining rapidly the octacalcium phosphate phase in the final 3D product, which is biocompatible.

Highlights

In the past decade, a several number of techniques for rapid prototyping of 3D bone grafts based on ceramics have been developed and widely applied[9,10,11,12]
Scanning electron micrographs of initial α-tricalcium phosphate (TCP) ceramic particles intended for fabrication of a CP-based 3D scaffold in a magnetic field are shown in Fig. S1 (Supporting Information)
The magnetic setup provides levitation of particles on the different height depending on the magnetophoretic force/gravity force ratio which in turn is regulated by concentration of paramagnetic salt in the medium (Fig. 1d)

Summary

Introduction

A several number of techniques for rapid prototyping of 3D bone grafts based on ceramics have been developed and widely applied[9,10,11,12]. The most frequently used techniques is mixing of ceramic particles with polymers followed by their 3D binding, and further high-temperature treatment[11,17] Another route based on inverse matrix-negative 3D printing, its filling with CP slurry, and heat processing for burning out the negative[10]. To compensate for gravity, levitation of CP requires several times greater magnetic force than levitation of living cells due to material density difference. This problem can be solved by using higher magnetic field gradient, which can be achieved by application of either superconductive electromagnets (or Bitter electromagnets) or higher concentrations of paramagnetic salts in medium. For the first time, we present successful fabrication via formative technology of biocompatible scaffold for the purpose of bone tissue engineering

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Conclusion