Lipoic acid as a linker to auranofin analogue on nanocellulose

Crystalline nanocellulose (CNC) is a readily available nanostructured form of cellulose, characterized by a high biocompatibility and easily functionalized to produce materials with new properties and applications. In this study, CNC was modified to act as a drug delivery system for the auranofin pharmacophore—specifically, the gold(I)-containing [Et3PAu]+ moiety. For this purpose, commercial CNC was first derivatized with propargyl groups and subsequently with lipoic acid. These two different functionalizations were then used to insert a simple glucose moiety (as a selector for tumor cells) using a CuAAC reaction with the propargyl end. Meanwhile the lipoic acid S-S bond was reduced with dithiothreitol to react with two equivalents of the gold complex Et3PAuCl, an analogue of auranofin. The modification of CNC afforded a nanohybrid characterized by a loading of 113.2 mg of Au and 0,41 mmol of selector per g of CNC and by a mean diameter of 290 nm and a Zeta Potential with a value of −51 ± 5 mV. This work opens the possibility of future studies on the use of Auranofin analogues supported on drug delivery systems for biomedical applications. future studies on the use of Auranofin analogues supported on drug delivery systems for biomedical applications.