Injectable and Biodegradable Chitosan Hydrogel-Based Drug Depot Contributes to Synergistic Treatment of Tumors

Combined therapy provides a more effective method in the treatment of tumors and becomes a research hotspot. To improve treatment outcomes and reduce serious side effects, hydrogel-based local delivery was developed herein to form a drug depot in suit to eliminate tumors. Indocyanine green and imiquimod were coencapsulated in the novel temperature-sensitive chitosan hydrogel. After intratumoral injection of the hydrogel, indocyanine green that accumulated in the tumor area could induce thermal ablation of primary tumors under laser irradiation. In the presence of imiquimod, the immune effects increased the probability of complete ablation of primary tumors and inhibition of metastases. Combined with cyclophosphamide, the enhanced immunological responses would further inhibit tumors and prolong the survival time. In a word, this work offered an excellent local delivery platform that enabled a remarkable combined antitumor strategy and achieved synergistic therapeutic effects.