Enhancing the Radical Scavenging Activity and UV Resistance of Lignin Nanoparticles via Surface Mannich Amination toward a Biobased Antioxidant

Abstract

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 in vitro 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 ortho-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.

Fabrication of UV- and Heat-Resistant PDLA/PLLA-g-Nanolignin Composite Films by Constructing Interfacial Stereocomplex Crystallites

“…The micromorphologies of LNP and the LNP- g -PLLA copolymer photographed by a transmission electron microscope are shown in Figure . The size of LNP is around 35 nm; meanwhile, the morphology of LNP- g -PLLA displayed that LNP were wrapped by PLLA (around 5 nm in thickness). The particle sizes of LNP before and after modification were also measured by transmission electron microscopy (TEM) and dynamic light scattering (DLS), and the result is presented in Figures S2 and S3.…”

“…In recent years, the lignin nanoparticles, due to their interesting UV block and anti-oxidative properties, have drawn much attention. The nanosized lignin has been tremendously considered in food packaging, skin cosmetic, and wound dressing biomedical applications. − …”

“…l -Lactide (99% purity) was earnestly furnished from Total Corbion, Netherlands. The original lignin was zealously offered by Longlive Co., Ltd.; in addition, lignin nanoparticles (LNP) were prepared according to our previous works. , All other required chemicals were purchased from Sinopharm Chemical Reagent Co., Ltd.…”

Preparation of lignin nanospheres based superhydrophobic surfaces with good robustness and long UV resistance

“…It is mainly composed of three phenylpropane units, containing rich aromatic ring structures, aliphatic, aromatic hydroxyl groups and quinone active groups. [1][2][3] As a byproduct of the chemical industry of forest products, lignin is mainly used as a fuel with low utilization value. In recent years, lignin nanospheres (LNPs) have become a research hotspot and showed great potential applications in drug delivery, electrochemistry, catalysis and other elds.…”

Design of Intrinsically Flame-Retardant Vanillin-Based Epoxy Resin for Thermal-Conductive Epoxy/Graphene Aerogel Composites

“…In the past two decades, biobased EPs have been considered to replace fossil-based alternatives: until now, plenty of bio-renewable feedstock materials, such as epoxidized soybean oils, , itaconic acid, cardanol, , and lignin − and its derivatives, − have aroused much attention for the preparation of EPs. Although great progress has been made in the preparation of these bio-renewable products, the comprehensive properties of EPs are limited, owing to the specific chemical structure and limited storages of bio-renewable raw materials.…”