Multiscale porosity in mesoporous bioglass 3D-printed scaffolds for bone regeneration

Mater Sci Eng C Mater Biol Appl. 2021 Jan:120:111706. doi: 10.1016/j.msec.2020.111706. Epub 2020 Nov 6.

Abstract

In order to increase the bone forming ability of MBG-PCL composite scaffold, microporosity was created in the struts of 3D-printed MBG-PCL scaffolds for the manufacturing of a construct with a multiscale porosity consisting of meso- micro- and macropores. 3D-printing imparted macroporosity while the microporosity was created by porogen removal from the struts, and the MBG particles were responsible for the mesoporosity. The scaffolds were 3D-printed using a mixture of PCL, MBG and phosphate buffered saline (PBS) particles, subsequently leached out. Microporous-PCL (pPCL) as a negative control, microporous MBG-PCL (pMBG-PCL) and non-microporous-MBG-PCL (MBG-PCL) were investigated. Scanning electron microscopy, mercury intrusion porosimetry and micro-computed tomography demonstrated that the PBS removal resulted in the formation of micropores inside the struts with porosity of around 30% for both pPCL and pMBG-PCL, with both constructs displaying an overall porosity of 8090%. In contrast, the MBG-PCL group had a microporosity of 6% and an overall porosity of 70%. Early mineralisation was found in the pMBG-PCL post-leaching out and this resulted in the formation a more homogeneous calcium phosphate layer when using a biomimetic mineralisation assay. Mechanical properties ranged from 5 to 25 MPa for microporous and non-microporous specimens, hence microporosity was the determining factor affecting compressive properties. MC3T3-E1 metabolic activity was increased in the pMBG-PCL along with an increased production of RUNX2. Therefore, the microporosity within a 3D-printed bioceramic composite construct may result in additional physical and biological benefits.

Keywords: Bone tissue engineering; Mesoporous bioactive glasses; Osteogenesis; Porosity; Scaffolds.

MeSH terms

  • Bone Regeneration*
  • Ceramics
  • Osteogenesis
  • Porosity
  • Printing, Three-Dimensional
  • Tissue Engineering
  • Tissue Scaffolds*
  • X-Ray Microtomography

Substances

  • Bioglass