纳米载体的出现极大改善了化疗药物的治疗效果。作为新兴的纳米载体，共价有机框架（COFs）近年来在生物医学领域的应用逐渐增多。然而，由于其固有的化学稳定性，现有的COF纳米载体在体内很难发生降解，给进一步应用带来了潜在的安全隐患。在这项工作中，我们向COFs中引入了偶氮键。当纳米载体进入细胞后，由配位的Fe对细胞内的H2O2产生的˙OH将会打断偶氮键并引起骨架结构的降解，加速内部加载的DOX的释放以有效实现肿瘤治疗。我们通过构建模型化合物、体外药物释放、MTT细胞生存率实验和抗肿瘤实验证实了材料的降解能力。与对照组相比，可降解COF加速了DOX的释放，并对4T1细胞表现出更强的杀伤作用。血清生化分析和器官的H&E切片显示COFs和降解产物的良好生物相容性。这项工作为体内可降解COFs的设计提供了新的思路，并大大探索了COF材料在生物医学领域的潜在应用。

The emergence of nanocarriers has greatly improved the therapeutic efficacy of chemotherapeutic drugs. As emerging nanocarriers, covalent organic frameworks (COFs) have been increasingly used in biomedicine in recent years. However, due to their inherent chemical stability, existing COF nanocarriers hardly undergo in vivo degradation, which brings potential safety hazards to further applications. In this work, we introduce the azo bond into COFs. When the nanocarrier enters the cell, ˙OH generated by the coordinated Fe response to the H2O2 in the cell will break the azo bond and cause the degradation of the framework structure, accelerating the release of internally loaded DOX to effectively realize tumor treatment. We verified the degradation ability of the materials by constructing model compounds, in vitro drug release, MTT assay and antitumor experiments. Compared with the control groups, the degradable COF accelerates the release of DOX and shows a stronger killing effect on 4T1 cells. Serum biochemical analysis and H&E sections of organs show good biocompatibility for both COFs and degradation products. This work provides a new idea for the design of biodegradable COFs in vivo, and greatly explores the potential application of COF materials in the biomedical field.