Fabrication of amine-decorated nonspherical microparticles with calcium peroxide cargo for controlled release of...

Oxygen is an important signaling molecule which affects many behaviors of bone progenitor cells. Oxygen releasing biomaterials depend on their material and design are able to provide and modulate the desired oxygen for cells. To date, many oxygen releasing vehicles have been developed by incorporating microsized calcium peroxide (CPO) into polymeric matrixes. However, an oxygen releasing system based on nano CPO is still lacking. Not only can nanosized CPO provide more controllable oxygen release, but also can be loaded in vehicles of different shapes and sizes. Current research was conducted to take the advantages of nanomaterials as oxygen releasing components. To this end, CPO nanoparticles were synthesized using a hydrolysis-precipitation procedure and then loaded into the poly (lactide-co-glycolide) (PLGA) matrix via an electrospray process. The surface of PLGA/CaO₂ particles was decorated with amine functionalities to render them more bioactive through a controlled aminolysis reaction. The studies on PLGA/CaO₂ microparticles revealed that biconcave disk-like morphology with a mean diameter of 5.3 μm was formed. The particles persistently provide oxygen content of 35-67.5 mmHg up to 14 days which lies within the acceptable range for bone tissue engineering applications. PLGA/CaO₂ microparticles induced 208 and 76% increase in number of viable mesenchymal cells on 6th and 14th days of cell seeding comparing PLGA counterparts. Furthermore, the expression of two bone biomarkers, that is, alkaline phosphatase and osteocalcin, at protein level as well as the extent of calcium deposition was increased in the presence of PLGA/CaO₂ microparticles compared to PLGA ones.