In vitro immune and redox response induced by cationic cellulose-based nanomaterials.

Cellulose nanocrystals (CNCs) display remarkable strength and physicochemical properties with significant potential applications. To better understand the potential adjuvanticity of a nanomaterial, it is important to investigate the extent of the immunological response, the mechanisms by which they elicit this response, and how this response is associated with their physicochemical characteristics. In this study, we investigated the potential mechanisms of immunomodulation and redox activity of two chemically related cationic CNC derivatives (CNC-METAC-1B and CNC-METAC-2B), using human peripheral blood mononuclear cells and mouse macrophage cells (J774A.1). Our data demonstrated that the biological effects caused by these nanomaterials occurred mainly with short term exposure. We observed opposite immunomodulatory activity between the tested nanomaterials. CNC-METAC-2B, induced IL-1β secretion at 2 h while CNC-METAC-1B decreased it at 24 h of treatment. In addition, both nanomaterials caused more noticeable increases in mitochondrial reactive oxygen species (ROS) at early time. The differences in apparent sizes of the two cationic nanomaterials could explain, at least in part, the discrepancies in biological effects, despite their closely related surface charges. This work provides initial insights about the complexity of the in vitro mechanism of action of these nanomaterials as well as foundation knowledge for the development of cationic CNCs as potential immunomodulators.