Dexamethasone loaded Laponite^®/porous calcium phosphate cement for treatment of bone defects

In this research, nanocomposite porous calcium phosphate cements (CPCs) consisting of dexamethasone (DEX) loaded Laponite^® nanoplates (LAP) (DEX-LAP) were fabricated and the effects of sodium bicarbonate (NaHCO₃) as the foaming agent on the physical, mechanical, and biological characteristics of DEX-LAP loaded CPCs were investigated. Our findings showed that DEX-LAP encapsulation significantly reduced the final setting time (1.5 times) of CPCs and accelerated the total transformation of tricalcium phosphate to hydroxyapatite. Moreover, DEX-LAP nanoplates meaningfully enhanced the compressive strength (4 fold) and compressive modulus (4 fold) of cement. Additionally, incorporation of 6% foaming agent noticeably reduced setting time of cement to less than 10 min due to the enhanced surface area in contact with cement paste. Encapsulation of DEX within the LAP nanoplates and consequently loading of DEX-LAP nanoplates in the CPCs resulted in the significantly reduced burst release of DEX. Finally, the results also illustrated that the presence of interconnected micropores and DEX-LAP nanoplates in the CPC improved MG63 cell proliferation. These findings suggest that the porous DEX-LAP/CPC can potentially be developed as bone grafts for bone defects.