Using Laponite to Deliver BMP-2 for Bone Tissue Engineering – In Vitro, Chorioallantoic Membrane Assay and Murine Subcutaneous Model Validation

Abstract

Fracture non-union occurs due to various factors, leading to the development of potentially substantial bone defects. While autograft and allograft are the current gold standards for non-union fractures, challenges related to availability and immune rejection highlight the need for improved treatments. A strategy in bone tissue engineering is to harness growth factors to induce an effect on cells to change their phenotype, behavior and initiate signaling pathways which lead to increased matrix deposition and tissue formation. Bone morphogenetic protein-2 (BMP-2) is a potent osteogenic growth factor however, given its rapid clearance time in vivo, there is a specific therapeutic window for efficacy while avoiding potential deleterious side-effects. It is demonstrated that a Laponite nanoclay coating on a 3D printable and bioresorbable poly(caprolactone) trimethacrylate-based resin enables binding of BMP-2, decreases the rate of release, enabling reduced concentrations to be used while enhancing osteoinduction in both in vitro and in vivo models.