In Vivo Study of Spiky Fe 3 O 4 @Au Nanoparticles with Different Branch Lengths: Biodistribution, Clearance, and Biocompatibility in Mice.

Magnetoplasmonic nanoparticles (Fe 3 O 4 @Au NPs) have been proven to be effective theranostic agents in genetic transmission and drug targeted delivery system as well as in photothermal treatment. Herein, two spiky magnetoplasmonic NPs with different branch lengths and numbers (short- and long-branched spiky Fe 3 O 4 @Au NPs) were specifically designed to determine theirs in vivo behaviors. The biocompatibility, biodistribution, and clearance of spiky Fe 3 O 4 @Au NPs were examined in mice. Organ distributions showed that intravenously administered spiky Fe 3 O 4 @Au NPs cumulated mainly in liver and spleen, and particle shape significantly affected their in vivo behaviors. The higher tendency in bioaccumulation of short-branched rather than long-branched spiky Fe 3 O 4 @Au NPs was observed in the spleen because long-branched spiky Fe 3 O 4 @Au NPs with a high aspect ratio were internalized more slowly than short-branched spiky Fe 3 O 4 @Au NPs. Serum biochemistry and transmission electron microscopy of ultrahistological structures indicated that spiky Fe 3 O 4 @Au NPs did not exhibit distinct toxicity in vivo and posed no potential risk of causing liver and kidney dysfunction. These findings lay the foundation for the design of future theragnostic agents.