Polymer-Lipid Hybrid Theranostic Nanoparticles Co-Delivering Ultrasmall Superparamagnetic Iron Oxide and Paclitaxel for Targeted Magnetic Resonance Imaging and Therapy in Atherosclerotic Plaque

Magnetic resonance imaging (MRI) combined with ultrasmall superparamagnetic iron oxide (USPIO) is effective for the detection of atherosclerotic (AS) plaque, and paclitaxel is effective for the treatment of AS. C11 is a polypeptide with high affinity and specificity for collagen IV. It is abundantly expressed in the outer layer of AS plaque. This study aimed to develop USPIO + paclitaxel-loaded polymer-lipid hybrid theranostic nanoparticles conjugated with C11 (UP-NP-C11) for simultaneous imaging and treatment AS plaque. UP-NP-C11 was developed by the nanoprecipitation method, and the theranostics of AS plaque by UP-NP-C11 were evaluated both in vitro and in the rabbit AS model. UP-NP-C11 was of desired particle size (140.2 nm), showed encapsulation efficiency of 35.5% and 55.2% for USPIO and paclitaxel, respectively, and had drug release profile. The accumulation of USPIO in Matrigel (containing abundant collagen IV) and macrophages coated on the Matrigel was significantly higher in the UP-NP-C11-treated group than in the group treated by UP-NP (USPIO + paclitaxel-loaded nanoparticles). Thus, UP-NP-C11 exerted better growth inhibitory effect and MRI ability in macrophages than UP-NP. Significantly, UP-NP-C11 showed better in vivo MRI ability and therapeutic effect in rabbit AS plaque than UP-NP and commercial USPIO + paclitaxel, and Prussian blue staining revealed significantly greater accumulation of USPIOs in the UP-NP-C11-treated group than in the control group. Furthermore, UP-NP-C11 did not cause severe toxicity to the rabbits. UP-NP-C11 represents a potential approach for targeted MRI and therapy in AS plaque.