External use of Nano-graphdiyne hydrogel for skin radioprotection via both physically shielding of Low-energy X-ray and chemically scavenging of Broad-spectrum free radicals

Skin radiation damage is one of the most common illnesses in external beam radiotherapy. One of the vital reasons for the damage occurrence is the low-energy X-rays contained in treatment radiations, which are greatly absorbed by skin to cause severe skin injury. Thus, the physical prevention that shields the harmful low-energy Xrays may be an effective skin radioprotective approach. However, at present, the existing commercial skin radioprotective drugs mainly adopt a single chemical repair pathway to eliminate the intracellular toxic free radicals and usually have limited treatment outcomes. Therefore, in order to improve the therapeutic effects of radiodermatitis during radiotherapy, we attempt to design a new drug that possesses dual-mode physical prevention and chemical repair approach to enhance skin radioprotection efficacy. Herein, we for the first time design and synthesize nanosized graphdiyne-loaded sodium hyaluronate hydrogel (nano-GDY@SH hydrogel), which possesses powerful broad-spectrum free radical scavenging activity by the nano-GDY and good low-energy X-ray attenuation ability by the hydrogel with high water content. The experimental results indicated that nanoGDY@SH hydrogel exhibits good biosafety, and can effectively decrease the low-energy X-ray-induced edema and ulcers of skin in mice, mitigate pathological lesion, reduce skin damage time and promote wound recovery.