n-Octadecyltrimethoxysilane (ODS)-modified silica particles were used as sole Pickering stabilizer to prepare water-in-oil Pickering high internal phase emulsions (HIPEs) with an internal phase volume of 80%. After polymerization of the continuous phase of HIPEs, interconnected macroporous polymers were obtained when modified silica was initially dispersed in water to form a micelle-like structure. However, silica particles in oil phase resulted in closed-cell pores. The pore size, the pore wall morphology, and the interconnectivity of polymer foams could be adjusted finely by the grafted amounts of ODS, modified silica concentrations, and the initial location of Pickering stabilizer. The gas permeation of interconnected porous polymers increased dramatically with the increase of the hydrophobicity of silica particles from 3 to 153 mL/min.
Creating interconnected macropores in calcium phosphate cement (CPC) is an effective strategy to promote its degradation and osteogenesis. However, little attention has been given to the osteogenic effect of the CPC scaffolds with pre-forming and in-situ forming interconnected macropores. Herein, two types of CPC scaffolds were prepared by infiltrating CPC pastes into 3D-printed polycaprolactone (PCL) and poly(lactic-co-glycolic acid) (PLGA) networks. Meanwhile, the sacrificial PCL network within CPC was dissolved to obtain the CPC scaffold with approximately 300 μm macropores, whereas the PLGA network was retained within the CPC to obtain the PLGA/CPC scaffold. The results indicated that the PLGA/CPC scaffold showed higher degradation rate and compressive strength compared to the CPC scaffold with pre-forming interconnected macropores. However, the proliferation rate and alkaline phosphatase activity of mouse bone mesenchymal stem cells cultured with the CPC scaffold were superior to those cultured with the PLGA/CPC scaffold. In addition, greater formation of new bone and material degradation in the CPC scaffold compared to the PLGA/CPC scaffold after implanted in the rabbit femoral defects.