The detrimental effect of cell adhesion on polymer surfaces has been a limiting factor in the medical deployment of many implants. We examined the potential to decrease cell proliferation while Simultaneously increasing mechanical performance through Zn-Al layered double hydroxide (LDH) organically modified with ibuprofen dispersed in poly(L-lactic acid) (PLLA). These composites are commonly referred to as nanocomposites. The thermo-physical and mechanical properties of the hybrids were Studied with wide-angle X-ray diffraction (WAXD), transmission electron microscopy (TEM), differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, and tensile testing. The WAXD and TEM results indicated that intercalated and exfoliated nanocomposites were obtained. The storage modulus, tensile modulus, and ultimate tensile strength were improved. The LDH affected the cold crystallization and reduced the thermal stability of the neat PLLA. Smooth muscle cells were used for in vitro studies of the nanocomposites. It was found that the hybrids reduced cell proliferation, and the amount of cell reduction was related to ibuprofen release. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 1905-1915,2009