Characterization, degradation and biocompatibility of PBAT based nanocomposites

The characterization, biocompatibility and hydrolytic degradation of poly(butylene adipate-co-terephthalate) (PBAT) and its nanocomposites based on 10 wt.% of an unmodified sepiolite and unmodified and modified montmorillonites and fluorohectorites were studied. All nanocomposites were prepared by melt blending using an internal mixer at 140 degrees C, showing a good level of clay distribution and dispersion into the PBAT matrix, especially those systems based on modified clays and sepiolite. The compression tests of all nanocomposites showed significant increases in the mechanical properties of PBAT matrix, associated to a reinforcement effect of nanoclays. An effective hydrolytic degradation of PBAT and nanocomposites in a phosphate buffered solution of pH 7.0 at 37 degrees C was also obtained. The addition of nanoparticles tended to delay slightly the hydrolysis of the polymer matrix in the early degradation stages; afterwards the presence of nanoparticles did not affect significantly the degradation trend of the polymer. Cytotoxicity tests, protein absorption analyses and complete blood count tests indicated that nanocomposites showed good biological safety: non-cytotoxicity, higher in vitro hemocompatibility than neat PBAT and non-negative hemostatic effects after contacting with blood. In general, these results showed that all the studied PBAT based nanocomposites could be very attractive for various tissue engineering applications, particularly to bone defects. (C) 2013 Elsevier B.V. All rights reserved.