Nanoparticles Containing Biocompatible Radicals Based on 1,2,4-Benzotriazinyl for Reactive Oxygen Species Scavenging in Living Cells

Abstract

We report the first demonstration using π-conjugated radicals for reactive oxygen species (ROS) scavenging. The ester-derived 1,2,4-benzotriazinyl monoradical VER and its carboxyl counterpart VAR exhibit typical antiferromagnetic behavior with a thermally populated spin-triplet state. Upon self-assembly with DSPE-PEG1000, VER formed ∼25 nm size nanoparticles (NPs) with good water dispersibility and stability, no obvious aggregation and degradation were observed after storing at ambient environment for 14 days. In contrast, VAR NPs were unstable and visible aggregates appeared on the seventh day. These radical NPs show good biocompatibility, there was almost no decrease in the cell viability after being incubated with either NPs even at a concentration of 100 μg/mL. Importantly, excessive ROS of the studied model RAW264.7 cells was scavenged to normal concentration when incubated with VER NPs, whereas ROS of VAR NPs treated model cells was almost not changed or even increased.