Chen Xin, Li Xiaojing, Xiao Yuting, Ding Lilin, Liu Lu, Qu Rui, Han Yang, Qian Yong
School of Chemistry and Chemical Engineering, State Key Laboratory of Advanced Papermaking and Paper-based Materials, South China University of Technology, Guangzhou, 510640, China.
Shiseido China Co., Ltd, China Innovation Center, 1558 Longdong Ave, Pudong New Area, Shanghai, 200120, China.
ChemSusChem. 2025 Apr 14:e2500454. doi: 10.1002/cssc.202500454.
Lignin holds significant potential in UV-blocking and skincare products. However, its application has been hindered by the dark color. Herein, a pink lignin (PL) is successfully extracted from birch under mild condition, with molecular weight and polydispersity index of 4680 Da and 1.38, respectively. As PL preserves the native structure of lignin, it retains 57.14% of β-O-4 linkages and 19.09% of methoxy groups, and possesses a whiteness index (WI) of -25. To address its limited absorption in long-wave UV irradiation, PL capsules with broad-spectrum UV absorption are developed by encapsulating chemical sunscreen actives via one-step ultrasonic cavitation. Optimal capsules with an average diameter of 180 nm are obtained using 3 wt% PL solution concentration, 8:2 mass ratio of PL to chemical sunscreen actives, and 7.5 wt% surfactant. Formulating sun creams with 10% and 15% PL capsules as the sole active ingredient achieves sun protection factor (SPF) values of 130+ and 180+, respectively. And their WIs maintain -18 and -22. Due to the excellent photostability of PL, the SPF value of the capsule-based sun cream decreases by only 18% after 7.5 h UV exposure. Moreover, the PL capsules exhibit good biocompatibility and have promising application potential.
木质素在紫外线防护和护肤品中具有巨大潜力。然而，其深色阻碍了它的应用。在此，在温和条件下成功从桦木中提取出粉色木质素（PL），其分子量和多分散指数分别为4680 Da和1.38。由于PL保留了木质素的天然结构，它保留了57.14%的β-O-4键和19.09%的甲氧基，并且白度指数（WI）为-25。为了解决其在长波紫外线照射下吸收有限的问题，通过一步超声空化封装化学防晒活性成分，开发出具有广谱紫外线吸收的PL胶囊。使用3 wt%的PL溶液浓度、PL与化学防晒活性成分8:2的质量比和7.5 wt%的表面活性剂，可获得平均直径为180 nm的最佳胶囊。以10%和15%的PL胶囊作为唯一活性成分配制防晒霜，其防晒系数（SPF）值分别达到130+和180+。并且它们的WI分别保持在-18和-22。由于PL具有优异的光稳定性，基于胶囊的防晒霜在紫外线照射7.5小时后，其SPF值仅下降18%。此外，PL胶囊表现出良好的生物相容性，具有广阔的应用潜力。
