Tuning the immune system response is an important factor in the development of new nanomaterials for applications in vivo. However, most macromolecular systems do not allow a systematic study of immune activation, given that the change of one chemical parameter usually causes important structural variations, complicating the relationship. To address this problem, we designed a series of structurally uniform nanoparticles that allow the study of specific chemical factors involved in different biological processes. Employing this family of nanoparticles with splenocytes as the experimental model, we determined the effect of hydrophobicity on the immune response, a parameter theorized to be involved in immune activation. For that purpose, cytokine expression profiles were contrasted against the calculated partition coefficient (LogP, a hydrophobicity index) of the nanoparticle headgroups. A linear increase in immune response was observed when hydrophobicity increased in vitro. Using mice as the experimental model a similar response was observed in vivo, with variations only at large hydrophobic values, caused principally by nanoparticle biodistribution. These results evidence the importance of hydrophobicity in immune activation, an issue of relevance for both harnessing and understanding the evolution of the innate immune system.

Hydrophobicity of nanoparticles dictates immune response in vitro and in vivo

244th National Meeting (2012)

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