Lignin particles (LPs) have gained prominence due to their biodegradability and bioactive properties. LP production at nano and micro scale produced from organosolv lignin and the understanding of size's effect on their properties is unexplored. This work aimed to produce and characterize lignin nanoparticles and microparticles using a green synthesis process, based on ethanol-solubilized lignin and water. Spherical shape LPs, with a mean size of 75 nm and 215 nm and with a low polydispersity were produced, as confirmed by transmission electron microscopy and dynamic light scattering. LPs thermal stability improved over raw lignin, and the chemical structure of lignin was not affected by the production method. The antimicrobial tests proved that LPs presented a bacteriostatic effect on E. coli and Salmonella enterica. Regarding the antioxidant potential, LPs had a high antioxidant activity that increased with the reaction time and LPs concentration. LPs also presented an antioxidant effect against intracellular ROS, reducing the intracellular ROS levels significantly. Furthermore, the LPs showed a low cytotoxic effect in Caco-2 cell line. These results showed that LPs at different scales (nano and micro) present biological properties and are safe to be used in different high value industrial sectors, such as biomedical, pharmaceutical and food.

木质素颗粒（LPs）由于其生物降解性和生物活性而倍受关注。由有机溶剂木质素生产的纳米级和微米级LP生产以及对尺寸对其性能影响的理解尚待探索。这项工作旨在使用绿色合成工艺，基于乙醇溶解的木质素和水，生产并表征木质素纳米颗粒和微粒。如透射电子显微镜和动态光散射所证实的，产生了平均尺寸为75nm和215nm且具有低多分散性的球形LP。LPs的热稳定性优于原料木质素，并且木质素的化学结构不受生产方法的影响。抗菌测试证明，LPs对大肠杆菌和大肠杆菌具有抑菌作用。沙门氏菌。关于抗氧化剂潜力，LP具有高的抗氧化剂活性，其随着反应时间和LP浓度的增加而增加。LPs还具有抗细胞内ROS的抗氧化作用，可显着降低细胞内ROS的水平。此外，LP在Caco-2细胞系中显示出低细胞毒性作用。这些结果表明，不同规模（纳米和微米）的LP具有生物学特性，可以安全地用于不同的高价值工业领域，例如生物医学，制药和食品。