The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, Jiangnan University, Wuxi 214122, China.
Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources and Joint International Research Lab of Lignocellulosic Functional Materials, Nanjing Forestry University, Nanjing 210037, China.
Biomacromolecules. 2021 Jun 14;22(6):2693-2701. doi: 10.1021/acs.biomac.1c00387. Epub 2021 Jun 2.
In recent years, lignin specific activities, such as antioxidation and antibacterial and anti-ultraviolet performance, have drawn more and more attention. Nevertheless, the insufficient radical scavenging (antioxidation) activity has become one of the main drawbacks that limits its high-value application. In this study, lignin nanoparticles (LNPs) were prepared via a facile acid treatment strategy. Subsequently, surface amination of LNPs (a-LNPs) was carried out through the Mannich reaction. Specifically, the antioxidant behavior of LNPs and modified LNPs was evaluated by DPPH/DMPO radical scavenging and HeLa cell reactive oxygen species (ROS) scavenging tests, which demonstrated that the antioxidation activity of a-LNPs was more evident than that of both LNPs and butylated hydroxytoluene (BHT) commercial antioxidant. The mechanism of the radical scavenging ability of aminated LNPs was elucidated and proved to be related to the bond dissociation enthalpy of Ar-O···H, determined by the electron-donating effect of the substituted groups in the -position. Meanwhile, the morphologies, solubilities, and UV-absorbing and antibacterial behavior of LNPs and a-LNPs were also studied, and the results showed that a-LNP sample exhibited higher UV resistance performance than LNPs. We expected that the modified LNPs with high antioxidation activity can serve as a safe and lower-cost biobased antioxidant.
近年来，木质素的特殊活性，如抗氧化、抗菌和抗紫外线性能，引起了越来越多的关注。然而，其自由基清除（抗氧化）活性不足，已成为限制其高附加值应用的主要缺点之一。在这项研究中，通过简便的酸处理策略制备了木质素纳米颗粒（LNPs）。随后，通过曼尼希反应对 LNPs 进行了表面氨基化（a-LNPs）。具体而言，通过 DPPH/DMPO 自由基清除和 HeLa 细胞活性氧（ROS）清除试验评估了 LNPs 和改性 LNPs 的抗氧化行为，结果表明 a-LNPs 的抗氧化活性比 LNPs 和商业抗氧化剂丁基羟基甲苯（BHT）更明显。阐明了氨基化 LNPs 清除自由基能力的机制，并证明与取代基在 - 位的供电子效应有关的 Ar-O···H 的键离解焓有关。同时，还研究了 LNPs 和 a-LNPs 的形态、溶解度、紫外吸收和抗菌行为，结果表明 a-LNP 样品表现出更高的抗紫外线性能。我们期望具有高抗氧化活性的改性 LNPs 可以作为一种安全且低成本的生物基抗氧化剂。
