Boron nitride nanotubes and nanoplatelets as reinforcing agents of polymeric matrices for bone tissue engineering

This study investigates the mechanical properties and in vitro cytotoxicity of one- and two-dimensional boron nitride nanomaterials-reinforced biodegradable polymeric nanocomposites. Polypropylene fumarate) (PPF) nanocomposites were fabricated using crosslinking agent N-vinyl pyrrolidone and inorganic nanomaterials: boron nitride nanotubes (BNNTs) and boron nitride nanoplatelets (BNNPs) dispersed at 0.2 wt % in the polymeric matrix. The incorporation of BNNPs and BNNTs resulted in a similar to 38 and similar to 15% increase in compressive (Young's) modulus, and similar to 31 and similar to 6% increase in compressive yield strength compared to PPF control, respectively. The nanocomposites showed a time-dependent increased protein adsorption for collagen I protein. The cytotoxicity evaluation of aqueous BNNT and BNNP dispersions (at 1-100 mu g/mL concentrations) using murine MC3T3 preosteoblast cells showed similar to 73-99% viability. The cytotoxicity evaluation of media extracts of nanocomposites before crosslinking, after crosslinking, and upon degradation (using 1 x-100x dilutions) showed dose-dependent cytotoxicity responses. Crosslinked nanocomposites showed excellent (similar to 79-100%) cell viability, cellular attachment (similar to 57-67%), and spreading similar to cells grown on the surface of tissue culture polystyrene control. The media extracts of degradation products showed a dose dependent cytotoxicity. The favorable cytocompatibility results in combination with improved mechanical properties of BNNT and BNNP nanocomposites opens new avenues for further in vitro and in vivo safety and efficacy studies towards bone tissue engineering applications. (C) 2015 Wiley Periodicals, Inc.