Controlling calcium and phosphate ion release of 3D printed bioactive ceramic scaffolds: An in vitro study

Abstract

This paper characterizes in an in vitro setting the release of calcium (Ca) and phosphate (PO 4 ) of 3D printed bioactive ceramic scaffold prepared from extrudable paste containing hydroxyapatite and β-tricalcium phosphate (β-TCP). Hydroxyapatite and β-TCP were calcined at 800 ℃ for 11 h, fabricated into four experimental groups (100% HA, 100% β-TCP, 15%/85% HA/β-TCP, and 15%/85% HA/β-TCP (design)), sintered to 1100 ℃ for 4 h. Calcium and phosphorus concentrations were evaluated using ICP spectroscopy, and the release of Ca and PO 4 ions during dissolution of the CaP-based scaffolds was measured by submerging in 0.05 mol/L Tris(hydroxymethyl)aminomethane-HCl and maintaining a temperature of 37 ℃. The Ca and PO 4 concentrations of the solutions were measured with the utilization of a calcium assay kit and a phosphate assay kit and read in a UV-visible spectrophotometer. The 100% HA scaffold group showed the greatest concentration of Ca ions (~1.9 mg/dL), but ultimately released at a lower amount as time increased; the 100% HA scaffold also showed the lowest total amount of calcium ions released over the course of evaluation. The results for the 100% β-TCP were on the opposite of the HA with the highest amount of calcium ion release over the study. While the PO 4 ion release showed a similar trend as those observed with Ca ions with an apparent difference in the 100% HA scaffold group. There was nearly 0 mg/dL of the phosphate ions released in the first 24 h, in comparison to the amount of Ca ions released during the same time frame. Since various formulations can lead to different properties of these bioactive ceramic scaffolds, it is important to understand how the tailoring of this important biphasic material can impact the long-term outcome of an ever-important in vivo clinical trial in the future.

Repair of Critical‐Sized Long Bone Defects Using Dipyridamole‐Augmented 3D‐Printed Bioactive Ceramic Scaffolds

“…Previously prepared, calcined and milled, β‐TCP (Product 21218, Lot 1305078; Sigma‐Aldrich, St. Louis, MO) powder was utilized to fabricate the 100% β‐TCP colloidal gel suspension. The colloidal gel was fabricated with a solids volume fraction of approximately 46%, (ϕ solids = ~0.46), the detailed gel fabrication process can be found in previous work by Lopez et al and Tovar et al…”

“…A–C). The custom‐built machine uses motion and flow‐rate controllers to deposit the colloidal ink through fine‐tipped nozzles, ~250‐μm‐diameter (EFD Inc., Nordson, Westlake, OH) . Identical to our previous 3D printing work, to produce a cylindrical structure, the software calculated a necessary support structure.…”

Thermal analysis of pure and multisubstituted hydroxyapatite pastes

“…and tetraethyl orthosilicate (C 2 H 5 O) 4 Si, (TEOS). Pure HAP and three doped hydroxyapatites with the same content of Mg, Zn, Si and different contents in Sr were obtained by a wet precipitation method, previously reported [6,10,13,26].…”

“…Nanocrystalline HAP paste is suitable bone substitute in dental and orthopedic surgery for filling bone defects in minimally invasive surgery. HAP pastes have various applications: as tooth pastes for remineralising and repairing of teeth enamel, for the fabrication of 3D printed bioactive ceramic scaffolds [2,4].…”

Complex phase evolution of Brushite-based calcium phosphate CaHPO4·2H2O using in situ high temperature X-ray diffraction and thermal analysis

“…The calcium-phosphate system constitutes an attractive class of materials in many elds of science and technology due to its diversity of compositions and structures, depending on the molar ratio Ca/P which can vary from 0.5 to 2 [1][2][3]. Several two and three-dimensional structures have been isolated and different synthesis strategies have been proposed.…”