Keratin-tannic acid complex nanoparticles as pH/GSH dual responsive drug carriers for doxorubicin. https://doi.org/10.1080/09205063.2021.1906074. 

Drug-loaded nanoparticles have been widely used in the field of tumor treatment due to their low side effects and reduced frequency of administration. In this study, pH and glutathione (GSH) dual-responsive keratin-tannic acid (TA) complex nanoparticles were established to trigger drug release under tumor microenvironments. Reductive keratin was first extracted using a reduction method. Then, keratin-TA complex nanoparticles (KNPs) were selfassembled via non-covalent interaction and further stabilized by self-crosslinking of thiols. This method was facile and green without chemicals during the whole procedure. KNPs exhibited pH and GSH dual responsiveness as well as charge reversibility in the simulated tumor microenvironment. The anticancer drug of doxorubicin (DOX) was loaded on KNPs by hydrophobicity and hydrogen bonds. Drug-loaded KNPs accelerated drug release under mimicked tumor microenvironments, performing high toxic against A549 cells while low toxic on normal cells. Besides, drugloaded nanoparticles could be endocytosed by tumor cells. Based on these results, KNPs may serve as drug carriers for therapeutic delivery