SrO‐ and MgO‐doped microwave sintered 3D printed tricalcium phosphate scaffolds: Mechanical properties and in vivo osteogenesis in a rabbit model

Abstract

The presence of interconnected macro pores allows guided tissue regeneration in tissue engineering scaffolds. However, highly porous scaffolds suffer from having poor mechanical strength. Previously, we showed that microwave sintering could successfully be used to improve mechanical strength of macro porous tricalcium phosphate (TCP) scaffolds. This study reports the presence of SrO and MgO as dopants in TCP scaffolds improves mechanical and in vivo biological performance. We have used direct three dimensional printing (3DP) technology for scaffold fabrication. These 3DP scaffolds possessed multiscale porosity, that is, 3D interconnected designed macro pores along with intrinsic micro pores. A significant increase in mechanical strength, between 37 and 41%, was achieved due to SrO and MgO doping in TCP as compared with pure TCP. Maximum compressive strengths of 9.38 ± 1.86 MPa and 12.01 ± 1.56 MPa were achieved by conventional and microwave sintering, respectively, for SrO‐MgO‐doped 3DP scaffolds with 500 μm designed pores. Histomorphological and histomorphometric analysis revealed a significantly higher osteoid, bone and haversian canal formation induced by the presence of SrO and MgO dopants in 3DP TCP as compared with pure TCP scaffolds when tested in rabbit femoral condyle defect model. Increased osteon and thus enhanced network of blood vessel formation, and osteocalcin expression were observed in the doped TCP scaffolds. Our results show that these 3DP SrO‐MgO‐doped TCP scaffolds have the potential for early wound healing through accelerated osteogenesis and vasculogenesis. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 679–690, 2015.

Effect of Chemistry on Osteogenesis and Angiogenesis Towards Bone Tissue Engineering Using 3D Printed Scaffolds

“…9 In our earlier studies, we examined the effect of binary doping on in vivo osteogenesis and angiogenesis in rat 13,51 and rabbit 52 models: (i) 1 wt.% SrO & 1 wt.% MgO 51,52 and (ii) 0.5 wt.% SiO2 & 0.25 wt.% ZnO 13 doped 3DP TCP scaffold. Multiscale porosity is a great feature of these scaffolds, which is exhibited by the presence of intrinsic micro pores along with the designed macro pores as shown in Figure 2.…”

“…% SrO and 1 wt. % MgO doped 3DP TCP scaffolds showed very promising induced bone formation caused by the presence of these dopants in TCP scaffolds in both rat 51 and rabbit 52 models.…”

Bridging the Gap: From 2D Cell Culture to 3D Microengineered Extracellular Matrices

“…For a more in depth review of 3D printing techniques we would like to refer the reader to the following reviews [209], [210]. A newly printed device can be used for biomedical applications as scaffolds[211]–[213], be used as a mold for creation of microfluidic devices [214], or cells can be directly printed for tissue engineering applications. Scaffolds have been fabricated by printing hard extracellular components of a tissue or organ which mimics the original composition and structure, and have been demonstrated for applications in bone tissue regeneration to increase osteogenesis and vaculogenesis[211]–[213], [215].…”

“…A newly printed device can be used for biomedical applications as scaffolds[211]–[213], be used as a mold for creation of microfluidic devices [214], or cells can be directly printed for tissue engineering applications. Scaffolds have been fabricated by printing hard extracellular components of a tissue or organ which mimics the original composition and structure, and have been demonstrated for applications in bone tissue regeneration to increase osteogenesis and vaculogenesis[211]–[213], [215]. These scaffold can be made to be biodegradable, allowing them to be replaced over time by growing bone[200] or cartilage[216].…”

Application of 3-D Printing for Tissue Regeneration in Oral and Maxillofacial Surgery: What is Upcoming?

“…Ceramic scaffolds are usually composed of calcium and phosphate mineral phases, such as hydroxyapatite [39] or b-tricalcium phosphate [40]. The noticeable ability of these scaffolds to upregulate osteogenesis due to inherent properties of the formation of a bioactive ion-rich cellular microenvironment, also as mentioned before their ability to mechanically provide space maintenance, makes these materials interesting choice for 3-D scaffold fabrication for craniofacial applications.…”