Antisense miR‐21 oligonucleotides (denoted as anti21) are chosen as the therapeutic sequence in the present work and delivered to cancer cells with FNCs, since silencing miR‐21 enables inhibition of vascular endothelial growth factor (VEGF) secretion and suppression of angiogenesis in the tumor.[14] After delivered effectively to breast cancer cells through circulation in a humanized orthotropic cancer model, anti21 is readily released in the cytosol upon NIR light illumination. Here, VEGFA is linked to breast cancer.