Lipoic acid as a linker to auranofin analogue on nanocellulose

Crystalline nanocellulose (CNC) is a readily available nanostructured form of cellulose, character-ized by a high biocompatibility and easily functionalized to produce materials with new propertiesand applications. In this study, CNC was modified to act as a drug delivery system for the aurano-fin pharmacophore—specifically, the gold(I)-containing [Et3PAu]þ moiety. For this purpose, com-mercial CNC was first derivatized with propargyl groups and subsequently with lipoic acid. Thesetwo different functionalizations were then used to insert a simple glucose moiety (as a selector fortumor cells) using a CuAAC reaction with the propargyl end. Meanwhile the lipoic acid S-S bondwas reduced with dithiothreitol to react with two equivalents of the gold complex Et3PAuCl, ananalogue of auranofin. The modification of CNC afforded a nanohybrid characterized by a loadingof 113.2 mg of Au and 0,41 mmol of selector per g of CNC and by a mean diameter of 290 nmand a Zeta Potential with a value of −51 6 5 mV. This work opens the possibility of future studieson the use of Auranofin analogues supported on drug delivery systems for biomedical applica-tions.