Preparation of Highly Bioactive Nanolignin via Dopamine Mannich Modification and Its Synergistic Effects With Zn2+ in PVA Hydrogels

en This link goes to a English section zh This link goes to a Chinese section Lignin is a natural non-toxic polyphenolic macromolecule, which shows inherent antioxidant and broad-spectrum antibacterial activities. However, due to the low content and the high bond dissociation energy of phenolic hydroxyl groups (Ar-O·H), its antioxidant and antibacterial activities are relatively weak, which limits its application as a highly bioactive biomaterial. In this study, different contents of dopamine (DA) were grafted onto the lignin nanoparticles (LNP) via a simple Mannich reaction to prepare LNP- x DA nanomaterial. LNP-1DA has an antibacterial rate of up to 99% against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ), and the antioxidant activity is 40% higher than that of LNP. Meanwhile, both LNP and LNP-DA have excellent blood and cell compatibility, whereas the hemolysis rate was less than 1% ( p < 0.001) and the cell viability for CCK-8 was higher than 95% ( p > 0.05). In order to further investigate its potential application as the bioactive wound-dressing additive, PVA/LNP-DA/Zn hydrogels were prepared by uniformly dispersing LNP-1DA in the Polyvinyl Alcohol (PVA) aqueous solution via the freezing-thawing approach, followed by immersing into the ZnCl 2 solution via an equilibrium method. The synergistic effects of LNP-1DA and Zn 2+ coordination endowed the hydrogels with improved mechanical properties (tensile strength up to 37.9 KPa) and antibacterial activity (antibacterial rate of 99%). This work will be of significance for the high-value utilization of lignin and the development of a novel bioactive material. 摘要 en This link goes to a English section zh This link goes to a Chinese section 木质素是一种天然无毒的多酚类大分子 , 具有固有的抗氧化和广谱抗菌活性。然而 , 由于其含量较低以及酚羟基 ( Ar-O·H ) 键解离能较高 , 导致其抗氧化和抗菌活性相对较弱 , 限制了其作为高生物活性生物材料的应用。本研究通过简单的曼尼希反应 , 将不同含量的多巴胺 ( DA ) 接枝到木质素纳米颗粒 ( LNP ) 上 , 制备出LNP-xDA纳米材料。LNP-1DA 对大肠杆菌 ( E. coli ) 和金黄色葡萄球菌 ( S . aureus ) 的抗菌率高达99% , 其抗氧化活性比LNP高出40%。同时 , LNP和LNP-DA均表现出优异的血液和细胞相容性 , 溶血率低于1% ( p < 0.001 ) , CCK-8检测的细胞存活率高于95% ( p > 0.05 ) 。为进一步探究其作为生物活性敷料添加剂的应用潜力 , 采用冷冻-解冻法将LNP-1DA均匀分散于聚乙烯醇 ( PVA ) 水溶液中 , 再通过平衡法浸入ZnCl₂溶液 , 制备了PVA/LNP-DA/Zn水凝胶。LNP-1DA与Zn²⁺配位产生的协同效应显著提升了水凝胶的力学性能 ( 拉伸强度达37.9 kPa ) 和抗菌活性 ( 抗菌率达99% ) 。本研究对木质素的高值化利用及新型生物活性材料的开发具有重要意义。