Fabrication of β‐tricalcium phosphate composite ceramic scaffolds based on spheres prepared by extrusion‐spheronization

Abstract

In this study, β‐tricalcium phosphate/phosphate‐based glass (β‐TCP/PG) composite spheres were prepared by an extrusion‐spheronization method featuring high production and fine control of sphere size. Subsequently, fully interconnected β‐TCP composite ceramic sphere‐based (TCCS) scaffolds were fabricated by sintering the randomly packed β‐TCP/PG composite spheres. The results manifested that at least 20% microcrystalline cellulose (MCC) was required to obtain β‐TCP/PG composite spheres in good spherical shape. The prepared TCCS scaffolds showed hierarchical pore architecture, which consisted of interconnected macropores among the spheres, a hollow core in the sphere, plentiful medium‐sized pores in the sphere shell and micropores among the grains. The pore architecture and mechanical strength of the TCCS scaffolds could be tailored by adjusting the sintering temperature, sphere size, and amounts of PG and MCC in the β‐TCP/PG composite spheres. This work is believed to open up new paths for the design and fabrication of interconnected bioceramic scaffolds for application in bone regeneration.

Modification of honeycomb bioceramic scaffolds for bone regeneration under the condition of excessive bone resorption

“…In this case, the positions of diffraction peaks for β‐TCP in the TCP‐GPGs patterns shifted to the higher angles, and the shift extent hinged on the Ga amount in the TCP‐GPGs. The ionic substitution can stabilize the phase stability of β‐TCP, and inhibit its reaction with PG in the sintering process; this explained why fewer or no β‐Ca 2 P 2 O 7 phase was shown in the TCP‐GPG2 and TCP‐GPG3, which were involved with the more ionic substitutions as compared with TCP‐GPG1 (Fig. C).…”

“…In the sintering process, the phosphorus-rich PG may react with β-TCP, giving rise to β-Ca 2 P 2 O 7 ; moreover, the metal ions of PG partially replace the Ca ions in the β-TCP lattice, leading to lattice distortion. 17,18,[35][36][37] The position of new peak in the patterns of TCP-GPG1 and TCP-GPG2 was overlapped with the strongest peak of β-Ca 2 P 2 O 7 (JCPDS # 09-346). It is inferred that the β-Ca 2 P 2 O 7 phase was produced as sintering TCP-GPG1 and TCP-GPG2 (Fig.…”

“…Great efforts have been made to increase the mechanical strength of β‐TCP bioceramics . Introduction of phosphate‐based glass (PG) additive is an efficient approach to improve the mechanical strength of β‐TCP bioceramics, because PG additive enables more effective liquid‐state sintering for β‐TCP . In general, the bioceramics are processed to porous form to conduct the bone growth.…”

“…[32][33][34] Introduction of phosphate-based glass (PG) additive is an efficient approach to improve the mechanical strength of β-TCP bioceramics, because PG additive enables more effective liquidstate sintering for β-TCP. 17,18,[35][36][37] In general, the bioceramics are processed to porous form to conduct the bone growth. It is generally regarded that the minimum pore size of 100 μm supports bone ingrowth, and the size >300 μm is more beneficial for vascularization.…”

Development of bioinks for 3D printing microporous, sintered calcium phosphate scaffolds

“…Another study using compacted pure β-TCP, which was densified at 1250 °C, reported a final grain size of 4.6 µm and compact material strength of ~75 MPa [ 37 ]. Moreover, β-TCP and phosphate-based glass composite scaffolds (prepared by extrusion spheronization and then sintered at 1100 °C), resulted in both hexagonal and tetragonal grains ranging from 1 to 20 µm in size; compressive strength of 14 MPa was reported for such scaffolds when the total porosity was 48% [ 38 ]. In comparison, by increasing the β-TCP fraction in the ink, and by sintering at 1240 °C, hexagonal grain sizes of 6.3 µm were obtained in the present study (Fig.…”