A general strategy towards an injectable microwave-sensitive immune hydrogel for combined percutaneous microwave ablation and immunotherapy

Abstract

The minimal invasive percutaneous microwave ablation (MWA) combined with immunotherapy is a promising technique in clinic for the treatment of primary and metastatic tumors. However, elaborate encapsulation carrier designs, complex cellular engineering, and poor applicability are the vexing problems difficult to solve currently. Herein, a general strategy was proposed for the design of an injectable microwave-sensitive immune hydrogel for combined MWA and immunotherapy in vivo for the first time. The mix-and-use hydrogel composed Food and Drug Administration (FDA)-approved components were fabricated by introducing various immunostimulants regardless of hydrophilicity and hydrophobicity into the alginate (ALG)-Ca2+ hydrogel. As a proof of concept, an immunoadjuvant (R837) was employed to synthesize the R837-ALG-hydrogel for systematic studies. This immune hydrogel owns ultra-facile synthesis process, good microwave-sensitivity, adjuvant encapsulation efficiency of nearly 100%, good biocompatibility and syringeability, and large-scale production capability, which could be easily injected into the primary tumor for enhancing MWA. Moreover, the loaded R837 could motivate in situ vaccination by making the utmost of the tumor-associated antigens released after MWA, thereby inducing the robust tumor-specific antitumor immunity to suppress the distant metastatic tumor in vivo. The proposed injectable microwave-sensitive immune hydrogel paves a facile but general avenue with great clinical translation potential for the minimal invasive personalized oncotherapy.