Ultrahigh-Efficacy VEGF Neutralization Using Carbonized Nanodonuts: Implications for Intraocular Anti-Angiogenic...

Ocular angiogenesis, associated with diseases such as retinopathy of prematurity and diabetic retinopathy, is a leading cause of irreversible vision loss. Herein, carbon nanodonuts (CNDs) with a donut-shaped structure are synthesized using sodium alginate (SA) and 1,8-diaminooctane (DAO) through a one-step thermal process. The formation of SA/DAO-CNDs occurs through a crosslinking reaction between SA and DAO, creating amide bonds followed by partial carbonization. In human retinal pigment epithelial cells exposed to H₂ O₂ or lipopolysaccharide, the SA/DAO-CNDs display a more than fivefold reduction in reactive oxygen species and proinflammatory cytokines, such as IL-6 and IL-1β, when compared to carbonized nanomaterials produced exclusively from SA. Furthermore, the CNDs effectively inhibit vascular endothelial growth factor A-165 (VEGF-A₁₆₅ )-induced cell migration and tube formation in human umbilical vein endothelial cells due to their strong affinity for VEGF-A₁₆₅ , with a dissociation constant of 2.2 × 10^-14  M, over 1600 times stronger than the commercial drug bevacizumab (Avastin). Trypsin digestion coupled with LC-MS/MS analysis reveals that VEGF-A₁₆₅ interacts with SA/DAO-CNDs through its heparin-binding domain, leading to activity loss. The SA/DAO-CNDs demonstrate excellent biocompatibility and potent anti-angiogenic effects in chicken embryos and rabbit eyes. These findings suggest that SA/DAO-CNDs hold promise as a therapeutic agent for treating various angiogenesis-related ocular diseases.