Pectin-coated boron nitride nanotubes: In vitro cyto-/immune-compatibility on RAW 264.7 macrophages

Background: Boron nitride nanotubes (BNNTs) represent a new opportunity for drug delivery and clinical therapy. The present work has the objective to investigate pectin-coated BNNTs (P-BNNTs) for their biocompatibility on macrophage cultures, since these cells are among the first components of the immune system to interact with administered nanoparticles. Methods: As first step, the potential toxicity of P-BNNTs is verified in terms of proliferation, oxidative stress induction and apoptosis/necrosis phenomena. Thereafter, the modulation of immune cell response following P-BNNT exposure is evaluated at gene and protein level, in particular focusing on cytokine release. Finally, P-BNNT internalization is assessed through transmission electron microscopy and confocal microscopy. Results: The results proved that P-BNNTs are not toxic for macrophages up to 50 mu g/ml after 24 h of incubation. The cytokine expression is not affected by P-BNNT administration both at gene and protein level. Moreover, PBNNTs are internalized by macrophages without impairments of the cell structures. Conclusions: Collected data suggest that P-BNNTs cause neither adverse effects nor inflammation processes in macrophages. General significance: These findings represent the first and fundamental step in immune compatibility evaluation of BNNTs, mandatory before any further pre-clinical testing. (C) 2016 Elsevier B.V. All rights reserved.