Structurally accurate lipophilic PtAg nanoclusters based cancer theranostic micelles for dual-targeting/aggregation enhanced fluorescence imaging and photothermal/photodynamic therapies.

Theranostics including imaging and therapy has become an advanced trend for cancer treatment. It is of great significance to develop new theranostics agent for precision medicine research. In this regard, structurally precise metal nanoclusters (NCs) with ultra-small diameter and potential theranostic functions are no doubt to be a priority. In this study, we firstly investigated the photothermal and photodynamic properties of structurally precise oil-soluble bimetallic NCs (PtAg) and tactfully solubilize them into the hydrophobic inner cavity of biodegradable amphiphilic chitosan derivative (ACD) micelles via hydrophobic interaction. Positively charged PtAg@ACD with suitable particle size (∼60 nm) could not only realize effectively passive targeted delivery, but also be easily uptaken by negatively charged cancer cells for increasing targeting effect. Further, the aggregation induced emission fluorescence imaging (AIE FI)-guided enhanced photothermal/photodynamic therapy (PTT/PDT) on tumor is finally nicely achieved by the micelle solubilization of ACD micelles to PtAg NCs, which were demonstrated by in vitro and in vivo experimental results. This theranostic platform overcomes the difficulty of lipophilic NCs entering water-phase organisms, provides enlightenment for the universal study of the interaction mechanism between organisms and oil-soluble NCs at the atomic level in future precision medicine research.