Advances in herbal polysaccharides-based nano-drug delivery systems for cancer immunotherapy.

The boom in cancer immunotherapy has provided many patients with a better chance of survival, but opportunities often come with challenges. Single immunotherapy is not good enough to eradicate tumours, and often fails to achieve the desired therapeutic effect because of the low targeting of immunotherapy drugs, and causes more side effects. As a solution to this problem, researchers have developed several nano Drug Delivery Systems (NDDS) to deliver immunotherapeutic agents to achieve good therapeutic outcomes. However, traditional drug delivery systems (DDS) have disadvantages such as poor bioavailability, high cytotoxicity, and difficulty in synthesis, etc. Herbal Polysaccharides (HPS), derived from natural Chinese herbs, inherently possess low toxicity. Furthermore, the biocompatibility, biodegradability, hydrophilicity, ease of modification, and immunomodulatory activities of HPS offer unique advantages in substituting traditional DDS. This review initially addresses the current developments and challenges in immunotherapy. Subsequently, it focuses on the immunomodulatory mechanisms of HPS and their design as nanomedicines for targeted drug delivery in tumour immunotherapy. Our findings reveal that HPS-based nanomedicines exhibit significant potential in enhancing the efficacy of cancer immunotherapy, providing crucial theoretical foundations and practical guidelines for future clinical applications.