Improving Phase Compatibility of PLA-PCL Matrix-Droplet Blend Using CNC/PCL-PEG-PCL Triblock Copolymer to Prepare Porous 3D Osteoinductive Scaffolds

Attempts were made to produce osteoinductive three- dimensional (3D) porous scaffolds with interconnected pores. Among the synthetic polymers, poly (ε- caprolactone) (PCL) was proven to be highly biocompatible and osteoinductive. However, it suffers from shrinkage due to high crystallinity and fast crystal growth. Here, we used polylactic acid, which is a rigid, low- crystalline and biocompatible polymer, as the major phase blended with PCL comprising the minor phase. However, these two polymers are highly incompatible and the PCL minor phase tend to form large droplets, distributing it unevenly throughout the continuous phase. Here, we used cellulose nanocrystals (CNCs), as a hydrophilic and osteoinductive nanoparticle, to suppress coalescence of PCL droplets and a tri-block copolymer of PCL-PEG-PCL (BCP) to reduce the interfacial tension of the two phases. 3D foams were prepared using thermally-induced phase separation and salt leaching and the porosity and pore size was tuned using CNC and BCP. The biocompatibility of the 3D scaffolds was evaluated by MG63 cell lines and the results indicated high biocompatibility. The scaffolds were also quite successful at inducing the osteogenesis of hMSCs. The specimen containing 10% BCP and 1.0% CNC had the highest calcium deposition with the highest expression of bone- specific genes.