In vitro flexural properties of hydroxyapatite and self-reinforced poly(L-lactic acid).

Poly(L-lactic acid) (PLLA) has been used for fracture fixation devices, but its use is limited because of its poor biocompatibility and mechanical properties. The effects of extrusion, incorporation of hydroxyapatite (HA) and self-reinforced composites (SRCs) on the resultant mechanical properties of PLLA were examined. Samples were conditioned for up to 52 weeks in PBS at 37 degrees C.

Nanoindentation of injection molded PLA and self-reinforced composite PLA after in vitro conditioning for three months.

Poly(lactic acid) (PLA) is used for medical devices such as sutures or orthopedic screws. A standard way to determine the loss of mechanical properties of a degradable polymer would be to soak the polymer in phosphate buffered saline (PBS) and test the desired property as a function of immersion time. This method is not sensitive enough to discern changes in mechanical properties through the cross-section of the polymer and neglects the degradation that is occurring at the molecular level.