National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Khlong Luang, Pathum Thani 12120, Thailand.
ACS Biomater Sci Eng. 2021 Jul 12;7(7):3114-3122. doi: 10.1021/acsbiomaterials.1c00366. Epub 2021 Jun 28.
Ultraviolet (UV) radiation from the sun is the most harmful factor for human skin, causing sunburn, melasma, freckles, blemishes, and skin cancer. Sunscreens play a key role in blocking UV absorption on the skin. This study focused on the synthesis of hollow polydopamine (h-PDA), whose structure mimics the naturally occurring melanin in humans, for use as an active ingredient in sunscreens by means of a hard-template-based method. The reactions involve a spontaneous polymerization of a dopamine monomer in the presence of tris(hydroxymethyl)aminomethane (Tris) as a catalyst onto a polystyrene (PS) core template. Different sizes of the PS core (about 280 and 450 nm) and weight ratios of PS/DA were applied to elucidate the effect of the hollow diameter and thickness of the shell on the morphology and absorbance of the synthesized h-PDA. From UV absorption results, it was observed that the synthesized h-PDA particles with a larger core diameter (about 450 nm) and a thin shell thickness (about 57 nm) presented high UV absorption. We found that the structure of the synthesized h-PDA is mainly composed of a mixture of 5,6-dihydroxyindole and indole-5,6-quinone precursors covalently linked together. After blending the h-PDA particles with the base cream, the formulation containing h-PDA with a large void diameter of about 450 nm showed the highest sun protection factor (SPF) of up to 7.43, which is related to % booster of 234.7%. In addition, the h-PDA particles exhibited biocompatibility and cellular uptake in keratinocyte HaCaT cells after 24 h of incubation, indicating the potential to mimic natural melanin in preventing UV-induced DNA damage, which could be safely used as an alternative sunscreen.
太阳的紫外线（UV）辐射是对人类皮肤最有害的因素，会导致晒伤、黄褐斑、雀斑、瑕疵和皮肤癌。防晒霜在阻止皮肤吸收紫外线方面起着关键作用。本研究专注于合成中空聚多巴胺（h-PDA），其结构模仿了人体内天然存在的黑色素，通过硬模板法将其用作防晒霜的活性成分。该反应涉及多巴胺单体在三羟甲基氨基甲烷（Tris）作为催化剂存在下的自发聚合，聚合在聚苯乙烯（PS）核模板上进行。应用不同大小的 PS 核（约 280 和 450nm）和 PS/DA 的重量比来阐明空心直径和壳层厚度对合成 h-PDA 的形态和吸收率的影响。从紫外线吸收结果来看，观察到具有较大核直径（约 450nm）和较薄壳厚度（约 57nm）的合成 h-PDA 颗粒具有高紫外线吸收。我们发现合成的 h-PDA 结构主要由 5,6-二羟基吲哚和吲哚-5,6-醌前体的混合物组成，这些前体通过共价键连接在一起。将 h-PDA 颗粒与基础霜混合后，含有约 450nm 大空隙直径的 h-PDA 的配方表现出高达 7.43 的最高防晒系数（SPF），这与 234.7%的增效剂有关。此外，h-PDA 颗粒在孵育 24 小时后在角质形成细胞 HaCaT 细胞中表现出生物相容性和细胞摄取，表明其在防止紫外线诱导的 DNA 损伤方面模拟天然黑色素的潜力，可安全用作替代防晒霜。
