Near-infrared absorbing nanoemulsions as nonlinear ultrasound contrast agents for cancer theranostics

Nanoemulsions serve as promising biomedical agents for cancer therapy and imaging. Recently, the development of perfluorocarbon (PFC) nanoemulsions has led to the ability of these nanoparticles to encapsulate therapeutic agents and vaporize into microbubbles and nanobubbles leading to cancer cell death. The PFC bubbles formed from nanoemulsions can serve as ultrasound contrast agents that can be used to verify the delivery of the nanoemulsion payload. In this work, perfluorohexane nanoemulsions (PFH-NEs) were synthesized for use as theranostic agents, by both encapsulating these nanoparticles with different chemotherapeutic agents (i.e. paclitaxel, doxorubicin) as well as to use the laser induced PFH bubbles to enhance the nonlinear ultrasound signals from cells for treatment monitoring. Since nonlinear ultrasound contrast arises specifically from the nonlinear scattering from oscillating microbubbles and nanobubbles and does not account for linear scattering from tissue, these PFH-NEs have the potential to effectively locate the tumor region for treatment monitoring.