7.2.3　Macroscale polymer materials

Unlike micromaterials or nanomaterials that can infiltrate tissue and cells，macroscale polymer materials with large size，can be implanted or local injected into the body to recruit and reprogram cells for in-situ expansion of T cells and continuously deliver therapeutic drugs.Furthermore，macroscale polymer materials can be used as the synthetic functional immunohistochemical analogues（e.g.，artificial lymph nodes），therefore，the materials draw more and more attentions.Compared with systemic administration，implantation or local injection is less toxic and can activate a more local immune response（see extended reading 5）.At present，macroscale materials used in melanoma immunotherapy mainly include polymer scaffolds，hydrogels and polymer microneedles，etc.(https://www.daowen.com)