Lignin-Based Nanoparticles for Combination of Tumor Oxidative Stress Amplification and Reactive Oxygen Species Responsive Drug Release.

In this study, maleic anhydride-modified lignin (LG-M), a ROS-cleavable thioketal (TK) bond, and polyethylene glycol (PEG) were used to synthesize a lignin-based copolymer (LG-M(TK)-PEG). Doxorubicin (DOX) was attached to the ROS-cleavable bond in the LG-M(TK)-PEG for the preparation of the ROS-activatable DOX prodrug (LG-M(TK-DOX)-PEG). Nanoparticles (NPs) with a size of 125.7 ± 3.1 nm were prepared by using LG-M(TK-DOX)-PEG, and they exhibited enhanced uptake by cancer cells compared to free DOX. Notably, the presence of lignin in the nanoparticles could boost ROS production in breast cancer 4T1 cells while showing little effect on L929 normal cells. This selective effect facilitated the specific activation of the DOX prodrug in the tumor microenvironment, resulting in the superior tumor inhibitory effects and enhanced biosafety relative to free DOX. This work demonstrates the potential of the LG-M(TK-DOX)-PEG NPs as an efficient drug delivery system for cancer treatment.