Preparation and imaging in vitro for perfluorohexane-encapsulated superparamagnetic poly (lactic-co-glycolic acid)-iron oxide multifunctional ultrasound contrast agents

Objective: To prepare multi-mode contrast agent, and to investigate its effect for ultrasound and MR imaging in vitro. Methods: Double emulsion method was used to prepare perfluorohexane-encapsulated superparamagnetic poly [lactic-co-glycolicacid, PLGA]-iron oxide (s-PFH/PLGA), and its morphology, size, Fe3O4 loading capacity and photoaccoustic detection were assessed. Then, the prepared s-PFH/PLGA microcapsules were applied with different concentrations to perform ultrasound imaging, and the echogenicity was assessed post irradiation using JC200 focused ultrasound tumor therapy system. Then s-PFH/PLGA microcapsules were also applied to perform MR imaging in vitro, and the signal intensity was calculated. Results: The s-PFH/PLGA microcapsules were observed with regular spherical morphology, the average size was (738.9±158.4)nm, average electric potential was (-15.9±6.9)mV, and photoaccoustic signal could be detected. In vitro, s-PFH/PLGA microcapsules showed hyper echogenicity in US imaging which increased after HIFU irradiation. In MRI, s-PFH/PLGA negatively enhanced on T2WI, and the signal intensity decreased with the increase of iron content. Conclusion: The prepared s-PFH/PLGA microcapsules can successfully act as contrast agent of ultrasound and MR imaging in vitro. Copyright © 2013 by the Press of Chinese Journal of Medical Imaging Technology.