Modification of primary amines to higher order amines reduces in vivo hematological and immunotoxicity of cationic nanocarriers through TLR4 and complement pathways

Randall Toy; Pallab Pradhan; Vijayeetha Ramesh; Nelson C. Di Paolo; Blake Lash; Jiaying Liu; Emmeline L. Blanchard; Philip J. Santangelo; Dmitry M. Shayakhmetov; Krishnendu Roy

Prior reports have evaluated nanoparticle toxicity by measuring in vitro innate immune activation in some ex vivo immune cells [26, 27, [34] [35] [36] , ex vivo complement activation in serum [30, 37, 38] , and changes in the protein corona after ex vivo incubation with serum [39] [40] [41] There are also a handful of studies that has reported that cationic polymers induce in vivo innate immune responses. However, comprehensive evaluation and relative contributions of hematological, hepatic, and immune reactions to the overall systemic toxicity profile of cationic polymer nanoparticles, and mechanism to alleviate them, has not been studied.. [25, 28] Although researchers have evaluated the effect of various small molecule modifications on the in vitro cytotoxicity of cationic nanoparticles, their effects on in vivo systemic toxicity, are poorly understood. Our results address several of these significant gaps in knowledge using chitosan and bPEI as exemplar cationic polymers, and IAA as an exemplar modification that reduces the primary amine content and increases tertiary amines in these polymers. .