Synergistic effect of scaffold composition and dynamic culturing environment in multi-layered systems for bone tissue engineering

摘要

Bone extracellular matrix (ECM) is composed of mineralized collagen fibrils which support biologicalapatite nucleation that participates in bone outstanding properties. Understanding and mimickingbone morphological and physiological parameters at a biological scale is a major challenge in tissueengineering scaffolding. Using emergent (nano)technologies scaffold designing may be criticallyimproved, enabling highly functional tissue substitutes for bone applications. This study aims to developnovel biodegradable composite scaffolds of tricalcium phosphate (TCPs) and electrospun nanofibersof poly(e-caprolactone) (PCL), combining TCPs osteoconductivity with PCL biocompatibilityand elasticity, mimicking bone structure and composition. We hypothesized that scaffolds with suchstructure/composition would stimulate the proliferation and differentiation of bone marrow stromalcells (BMSCs) towards the osteogenic phenotype. Composite scaffolds, developed by electrospiningusing consecutive stacked layers of PCL and TCPs, were characterized by FTIR spectroscopy, X-Ray diffractionand scanning electronic microscopy. Cellular behavior was assessed in goat BMSCs seededonto composite scaffolds and cultured in static or dynamic conditions, using basal or osteogenic mediaduring 7, 14 or 21 days. Cellular proliferation was quantified and osteogenic differentiation confirmedby alkaline phosphatase activity, alizarin red staining and immunocytochemistry for osteocalcin andcollagen I. Results suggest that PCL-TCP scaffolds provide a 3D support for gBMSCs proliferationand osteogenic differentiation with production of ECM. TCPs positively stimulate the osteogenicprocess, especially under dynamic conditions, where PCL-TCP scaffolds are sufficient to promoteosteogenic differentiation even in basal medium conditions. The enhancement of the osteogenicpotential in dynamic conditions evidences the synergistic effect of scaffold composition and dynamicstimulation in gBMSCs osteogenic differentiation.