Here we develop nanocomposites based on polylactide (PLA) and zinc oxide (ZnO) nanoparticles for packaging and biomedical applications. Mechanically flexible films have been prepared by a simple scalable industrial process. We observe that ultraviolet light could be blocked by 61.2% for a concentration as low as 0.45 vol %, while the 95.9% of the visible radiation passes through the material. Dynamic mechanical analysis exhibits a Tg increase with nanoparticle loading arising from the chain confinement caused by the presence of ZnO interacting surfaces, while the structural relaxation of nanocomposites is reduced 3.6 times after the addition of 0.25 wt.% of zinc oxide. We further analyze the catalytic effect of zinc oxide during the in vitro hydrolytic degradation of PLA/ZnO nanocomposites. We observe that during hydrolytic degradation H2O is dissociated on oxygen vacancy sites, giving hydroxyl groups that initiate the hydrolysis of ester bonds, and thus reducing PLA to soluble monomers. These findings are expected to allow the development of eco-friendly disposable polymeric waste by opening new possibilities in the use of naturally-available materials as efficient catalysts for feedstock recycling of biopolymers by common chemical processes. Overall, this work highlights the potential for these sustainable nanostructured functional materials to be used in packaging applications, where the use of non-biodegradable materials for short-term applications is extended. In view to biological applications, we further demonstrate that the system constitutes a dynamic surface in which nanoparticles are continuously exposed upon C2C12 myoblasts cell culture, activating the material surface and significantly driving cell differentiation. Moreover, we observe that PLA/ZnO scaffolds profile could be successfully modified by tuning both the amount of ZnO nanoparticles. Overall, results suggest that PLA/ZnO nanocomposites may serve to develop antibacterial porous structures with tunable degradation rates to be used as a substrate for the growth of different kind of cells and tissues.

Polylactide/ZnO nanocomposites: From improved functional properties for packaging to novel materials for biomedicine

253rd National Meeting (2017)

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