A facile preparation method of a PFC-containing nano-sized emulsion for theranostics of solid tumors

Theranostics means a therapy conducted in a diagnosis-guided manner. For theranostics of solid tumors by means of ultrasound, we designed a nano-sized emulsion containing perfluoropentane (PFC5). This emulsion can be delivered into tumor tissues through the tumor vasculatures owing to its nano-size, and the emulsion is transformed into a micron-sized bubble upon sonication through phase transition of PFC5. The micron-sized bubbles can more efficiently absorb ultrasonic energy for better diagnostic images and can exhibit more efficient ultrasound-driven therapeutic effects than nano-sized bubbles. For more efficient tumor delivery, smaller size is preferable, yet the preparation of a smaller emulsion is technically more difficult. In this paper, we used a bath-type sonicator to successfully obtain small PFC5-containing emulsions in a diameter of ca. 200 nm. Additionally, we prepared these small emulsions at 40 degrees C, which is above the boiling temperature of PFC5. Accordingly, we succeeded in obtaining very small nano-emulsions for theranostics through a very facile method. (C) 2011 Elsevier B.V. All rights reserved.