Resorbable composite scaffolds for craniofacial bone tissue engineering

Abstract

Aim:
Bone loss associated with trauma, osteo-degenerative diseases and tumors has
tremendous socioeconomic impact related to personal and occupation disability and
health care costs. In the present climate of increasing life expectancy with an ensuing
increase in bone-related injuries, orthopaedic surgery is undergoing a paradigm shift
from bone-grafting to bone engineering, where a scaffold is implanted to provide
adequate load bearing and enhance tissue regeneration. We aim to develop composite
scaffolds for bone tissue engineering applications to replace the current gold standard
of autografting. ----------
Methods:
Medical grade polycaprolactone-tricalcium phosphate (mPCL/TCP) scaffolds (80/20
wt%) were custom made using fused deposition modelling to produce 1x1.5x2 cm sized
implants for critical-sized pig cranial implantations, empty defects were used as a
control. Autologous bone marrow stromal cells (BMSCs) were extracted and precultured
for 2 weeks, dispersed within fibrin glue and injected during scaffold
implantation. After 2 years, microcomputed tomography and histology were used to
assess bone regenerative capabilities of cell versus cell-free scaffolds. ----------
Results:
Extensive bone regeneration was evident throughout the entire scaffold. Clear
osteocytes embedded within mineralised matrix and active osteoblasts present around
scaffold struts were observed. Cell groups performed better than cell-free scaffolds. ----------
Conclusions:
Bone regeneration within defects which cannot heal unassisted can be achieved using
mPCL/TCP scaffolds. This is improved by the inclusion of autogenous BMSCs. Further
work will include the inclusion of growth factors including BMP-2, VEGF and PDGF to
provide multifunctional scaffolds, where the three-dimensional (3D) template itself acts
as a biomimetic, programmable and multi-drug delivery device.