Ultrasound responsive Gd-DOTA/doxorubicin-loaded nanodroplet as a theranostic agent for magnetic resonance image-guided controlled release drug delivery of melanoma cancer.

Theranostic agents use simultaneous for diagnostic and therapeutic procedures. In the present study, the effect of Gd-DOTA/doxorubicin-loaded perfluorohexane nanodroplets as a theranostic nanoparticle for control released drug delivery and ultrasound/MR imaging was investigated on B16F10 melanoma cancer cells. The intracellular uptake was performed by inductively coupled plasma optical emission spectrometry (ICP-OES) that indicated sonicated Gd-DOTA/DOX@PFH NDs uptake by cancer cells was approximately 1.5 times more than the non-sonicated nanodroplets after 12 h. In vitro and in vivo toxicity assays revealed that synthesized NDs are biocompatible and do not have organ toxicity. Ultrasound exposure significantly enhanced the release of doxorubicin from NDs (P-value< 0.05). Ultrasound echogenicity and T1-MRI relaxometry indicated that synthesized NDs have strong ultrasound signal intensity and high r1 relaxivity (6.34 mM-1 S-1). The concentration of DOX in mice vital organs for Gd-DOTA/DOX NDs was significantly lower than that of free DOX. Doxorubicin concentration after 150 min in the tumor region for the DOX-loaded Gd-NDs+US group reached 14.8 µg/g followed by sonication, which was 2.3 fold higher than that of the non-sonicated group. According to the obtained results, the synthesized nanodroplets, with excellent diagnostic (ultrasound/MRI) and therapeutic properties, could be promising theranostic agents in cancer imaging and drug delivery for chemotherapeutic application.