Biomedical nanocomposites of poly(lactic acid) and calcium phosphate hybridized with modified carbon nanotubes for hard tissue implants

Degradable polymer‐based materials are attractive in orthopedics and dentistry as an alternative to metallic implants for use as bone fixatives. Herein, a degradable polymer poly(lactic acid) (PLA) was combined with novel hybrid nanopowder of carbon nanotubes (CNTs)‐calcium phosphate (CP) for this application. In particular, CNTs‐CP hybrid nanopowders (0.1 and 0.25% CNTs) were prepared from the solution of ionically modified CNTs ( m CNTs), which was specifically synthesized to be well‐dispersed and thus to effectively adsorb onto the CP nanoparticles. The m CNTs‐CP hybrid nanopowders were then mixed with PLA (up to 50%) to produce m CNTs‐CP‐PLA nanocomposites. The mechanical tensile strength of the nanocomposites was significantly improved by the addition of m CNTs‐CP hybrid nanopowders. Moreover, nanocomposites containing low concentration of m CNTs (0.1%) showed significantly stimulated biological responses including cell proliferation and osteoblastic differentiation in terms of gene and protein expressions. Based on this study, the addition of novel m CNT‐CP hybrid nanopowders to PLA biopolymer may be considered a new material choice for developing hard tissue implants. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.