Radio-opaque theranostic nanoemulsions with synergistic anti-cancer activity of paclitaxel and Bcl-2 siRNA

The integration of therapeutic and imaging functions in a nanoscale structure is gaining increasing attention to monitor drug and gene delivery in a non-invasive real-time manner. Here we introduce radio-opaque nanoemulsions incorporating paclitaxel and Bcl-2 small interfering RNA (siRNA) for synergistic anti-cancer theranostics. Water-insoluble paclitaxel is readily dissolved in iodinated poppy seed oil (Lipiodol) and emulsified in an aqueous solution using a mixture of PEGylated phospholipids, cholesterols, and linear polyethylenimine grafted with cholesterols. The prepared cationic nanoemulsions were electrostatically complexed with Bcl-2 siRNA for the co-delivery of paclitaxel and siRNA, inducing a dramatically higher level of apoptosis and cytotoxic activity in breast adenocarcinoma compared to individual treatments. The feasibility of the nanoemulsions for bio-imaging applications is preliminarily investigated using micro-computed tomography with a mouse model. This study suggests that the Lipiodol nanoemulsions can be used as a multifunctional nanocarrier platform for the co-delivery of anti-cancer drugs and siRNA with bio-imaging functionality to efficiently increase the modality of anti-cancer theranostics.