CAT and neoplasm: To solve the problem that the inherent hypoxic tumor microenvironment limits the efficacy of PDT, Liu et al.92 reported a multi-functional DNA nanorod, which is constructed by the RCA reaction, for effective co-loading and delivery of photosensitizers, catalase and hypoxia-inducible factor 1α (HIF-1α) antisense DNA (Fig. 10D).