title: Beta-type calcium phosphates with and without magnesium: From hydrolysis of brushite powder to robocasting of periodic scaffolds.
abstract: Several approaches have attempted to replace extensive bone loss, but each of them has their limitation. Nowadays, additive manufacture techniques have shown great potential for bone engineering. The objective of this study was to synthesize beta tricalcium phosphate (β-TCP), beta tricalcium phosphate substituted by magnesium (β-TCMP), and biphasic calcium phosphate substituted by magnesium (BCMP) via hydrolysis and produce scaffolds for bone regeneration using robocasting technology. Calcium deficient apatites, with and without magnesium were obtained by hydrolysis, calcined and physico-chemically characterized. Colorimetric cell viability assay, calcium nodule formation, and the expression of alkaline phosphatase, osteocalcin, transforming growth factor beta-1 and collagen were assessed using a mouse osteoblastic cell line (MC3T3-E1). Direct-write assembly of cylindrical periodic scaffolds was done via robotic deposition using β-TCP, β-TCMP, and BCMP colloidal inks. The sintered scaffolds were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, Archimede's method, and uniaxial compression test. According to the cell viability assay, the powders induced cell proliferation. Calcium nodule formation and bone markers activity suggested that the materials present potential value in bone tissue engineering. The scaffolds built by robocasting presented interconnected porous and exhibited mean compressive strength between 7.63 and 18.67 MPa, compatible with trabecular bone.
authors.affiliation: Metallurgical and Materials Department, Federal University of Rio de Janeiro-UFRJ/COPPE, CP 68505, CEP 21945-970, Rio de Janeiro, RJ, Brazil.
authors.forename: Raquel C
authors.initials: RC
authors.lastname: Richard
authors.forename: Márcia S
authors.initials: MS
authors.lastname: Sader
authors.forename: Jisen
authors.initials: J
authors.lastname: Dai
authors.forename: Rossana M S M
authors.initials: RM
authors.lastname: Thiré
authors.forename: Gloria D A
authors.initials: GD
authors.lastname: Soares
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D006868:Hydrolysis; D008274:Magnesium / Q000494:pharmacology*; D051379:Mice; D011208:Powders; D012371:Robotics / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D002130:Calcium Phosphates; D011208:Powders; C485817:beta-tricalcium phosphate; D008274:Magnesium; C494366:calcium phosphate, dibasic, dihydrate
keywords: bone engineering; calcium phosphates hydrolysis; magnesium substitution; robocasting; scaffolds