Controlled PLGA degradation within Calcium Phosphate Cement for Bone Tissue Engineering

摘要

Calcium phosphate cements (CPCs) are increasingly used as bone substitute materials. Porosity and pore size of CPC scaffolds play a critical role in bone formation. CPCs present intrinsic nanoporosity that enables fluid flow inside the composite but it is too small for tissue ingrowth. Macroporosity is an important parameter to enhance tissue ingrowth and CPC degradation. PLGA (Poly (D,L-lactic-co-glycolic) acid) microspheres can be included in CPC and after degradation a porous CPC scaffold is obtained. The loss of mechanical strength due to the degradation of PLGA microspheres is ideally compensated by bone ingrowth inside the CPC scaffold. It has been described that PLGA degradation is affected, among other factors, by the molecular weight of the polymer. In this study different PLGA molecular weights and different end terminations are tested to fine tune polymer degradation in CPC. To study the polymer degradation a new High Pressure Liquid Chromatography (HPLC) method to quantify lactic and glycolic acid monomers has been developed.