Facile Synthesis of Lipid–Perfluorocarbon Nanoemulsion Coated with Silica Shell as an Ultrasound Imaging Agent

Abstract

A novel organic/inorganic hybrid nanovesicle as an ultrasound imaging agent is synthesized via facile emulsion and silica deposition methods. This nanovesicle, hyaluronate (HA)–docetaxel (DTX)/perfluoro-n-pentane (PFP)@SNC, consists of an encapsulated liquid PFP core, loaded DTX, and an HA-decorated silica shell. The HA–DTX/PFP@SNC has a narrow size distribution of 274.5 ± 3.25 nm, a negative zeta potential of −11.6 ± 0.47 mV, and an entrapment efficiency of 86.70% ± 1.42%. HA–DTX/PFP@SNC possesses an ultrasound (US)-triggered drug release and a temperature-dependent size change behavior. Compared with DTX/PFP@soybean phosphatidylcholine (SPC), which has no silica shell, the HA–DTX/PFP@SNC is more stable under various conditions. The MTT assay indicates that the blank HA–PFP@SNC vehicle has no cytotoxicity to A549 cells. Furthermore, due to the HA-mediated tumor-targeting ability, the HA–DTX/PFP@SNC shows obvious cytotoxicity to A549 cells. In vitro and in vivo US imaging results indicate that HA–DTX/PFP@SNC has a stronger and more durable echo signal than DTX/PFP@SPC. Moreover, the in vivo echo signal of HA–DTX/PFP@SNC is stronger than that of DTX/PFP@SNC due to the HA-mediated tumor targeting. Therefore, this novel organic/inorganic hybrid vesicle is a US contrast agent candidate.

A novel organic/inorganic hybrid nanovesicle is fabricated using new and facile emulsion and silica deposition methods. The soybean phosphatidylcholine (SPC) nanoemulsion containing perfluoro-n-pentane and docetaxel (DTX/PFP@SPC) is first encapsulated with silica shell, which is then decorated with hyaluronate molecules (HA–DTX/PFP@SNC). The vesicle exhibits high drug entrapment efficiency, good stability, ultrasound-triggered drug release, tumor-targeting ability, and satisfactory ultrasound imaging.

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