Nanoparticle Hydrophobicity Dictates Immune Response

TLDR

Interactions of nanomaterials with the immune system are essential for engineering new macromolecular systems for in vivo applications, yet systematic study of immune activation is challenged by the complex structure of most probes. The study uses engineered gold nanoparticles to isolate the effect of hydrophobicity on splenocyte immune response. Gold nanoparticles with controlled hydrophobicity were employed to assess splenocyte immune activation. Gene expression of cytokines increased linearly with nanoparticle hydrophobicity in vitro, and similar trends were observed in vivo, confirming hydrophobicity drives immune activation.

Abstract

Understanding the interactions of nanomaterials with the immune system is essential for the engineering of new macromolecular systems for in vivo applications. Systematic study of immune activation is challenging due to the complex structure of most macromolecular probes. We present here the use of engineered gold nanoparticles to determine the sole effect of hydrophobicity on the immune response of splenocytes. The gene expression profile of a range of cytokines (immunological reporters) was analyzed against the calculated log P of the nanoparticle headgroups, with an essentially linear increase in immune activity with the increase in hydrophobicity observed in vitro. Consistent behavior was observed with in vivo mouse models, demonstrating the importance of hydrophobicity in immune system activation.