Remodeling the tumor immune microenvironment through hydrogel encapsulated G-Rh2 in situ vaccine and systemic immunotherapy

Ginsenoside Rh2 (G-Rh2) is a vital bioactive compound in Traditional Chinese Medicine, celebrated for its strong pharmacological properties, particularly its potent antitumor effects. However, its poor water solubility and limited bioavailability have necessitated the development of a novel drug delivery method. In this study, we utilized an indocyanine green carboxylic acid-hydroxypropyl cellulose-abietic acid-bovine serum albumin hydrogel (ICG-HPC-AA/BSA hydrogel) as a tumor <i>in situ</i> vaccine to enhance the permeability, retention, and tumor-targeted therapeutic efficacy of G-Rh2. We examined the therapeutic impact of a G-Rh2-loaded hydrogel combined with systemic PD-1 antibody treatment in murine models of H22 liver cancer and CT26 colon cancer. Additionally, we explored the immune microenvironment of the tumors influenced by this <i>in situ</i> vaccination strategy.