3D-CEUS tracking of injectable chemo-sonodynamic therapy-enabled mop-up of residual renal cell carcinoma after thermal ablation

Thermal ablation (TA), as a minimally invasive therapeutic technique, has been extensively used to the treatment of solid tumors, such as renal cell carcinoma (RCC), which, unfortunately, still fails to overcome the high risk of local recurrence and distant metastasis since the incomplete ablation cannot be ignored due to various factors such as the indistinguishable tumor margins and limited ablation zone. Herein, we report the injectable thermosensitive hydrogel by confining curcumin (Cur)-loaded hollow mesoporous organosilica nanoparticles (Cur@HMON@gel) which can locate in tumor site more than half a month and mop up the residual RCC under ultrasound (US) irradiation after transforming from colloidal sol status to elastic gel matrix at physiological temperature. Based on the US-triggered accelerated diffusion of the model chemotherapy drug with multi-pharmacologic functions, the sustained and controlled release of Cur has been demonstrated in vitro. Significantly, US is employed as an external energy to trigger Cur, as a sonosensitizer also, to generate reactive oxygen species (ROS) for sonodynamic tumor therapy (SDT) in parallel. Tracking by the three-dimensional contrast-enhanced ultrasound (3D-CEUS) imaging, the typical decreased blood perfusions have been observed since the residual xenograft tumor after incomplete TA were effectively suppressed during the chemo-sonodynamic therapy process. The high in vivo biocompatibility and biodegradability of the multifunctional nanoplatform confined by thermogel provide the potential of their further clinical translation for the solid tumor eradication under the guidance and monitoring of 3D-CEUS.