Supramolecular design of coordination bonding architecture on zein nanoparticles for pH-responsive anticancer drug delivery.

A pH-responsive system by constructing a designable coordination bonding-based metal-tannic acid (TA) architecture on zein nanoparticles (NPs) has been investigated. Film formation was initiated by the adsorption of the polyphenol and directed by pH-dependent, multivalent coordination bonding. The prepared metal-TA coated zein NPs (zein-TA/metal NPs) demonstrated good stability to maintain particle size in cell culture medium at 37 °C. The microstructure of the NPs was revealed by transmission electron microscopy (TEM). To confirm the surface chemical information of the NPs, XPS analysis was performed. Furthermore, in vitro viability studies revealed that the zein-TA/metal NPs showed no significant cytotoxicity against HepG2 cells for 24h. Because of the pH-responsive coordination bonding between TA and metal ions, the functional property of the metal-TA films was tailored for drug delivery. Biocompatible AuNPs were produced using zein-TA/metal NPs as reducing and stabilizing agents which were promising in the photothermal therapy of cancers and other diseases.