Precision-engineered lignin-based antimicrobial and antioxidant nanomaterials: New insights into chemistry, mechanisms, reinforcement strategies and application advances

Bacterial infections and antibiotic resistance pose critical global health challenges, driving demand for sustainable antimicrobial solutions. Lignin-based antimicrobial and antioxidant nanomaterials (LANs) have emerged as promising alternatives to conventional antimicrobials due to their intrinsic bioactivity, renewability, and biocompatibility. While previous reviews have primarily catalogued lignin's properties and activities, a systematic understanding of the structure-property-performance relationships governing LANs remains lacking. This review addresses this critical gap by providing an integrated and mechanistic perspective on LANs. It begins by elucidating the fundamental chemistry and structure-activity relationships governing lignin’s bioactivity, including the roles of phenolic hydroxyl content, molecular weight, S/G ratio, and interunit linkage patterns. The review then critically examines the multifaceted antioxidant and antimicrobial mechanisms of lignin, with particular emphasis on its dual role in the generation and scavenging of reactive oxygen species (ROS), and how this duality can be harnessed for therapeutic benefit. Subsequently, key enhancement strategies like chemical modification, nanolignin fabrication, solvent fractionation, and compositing with metals or organic agents are systematically evaluated in terms of their impact on antibacterial efficacy and application suitability. Finally, the review surveys recent advances in LAN applications across biomedicine, food packaging, textiles, and cosmetics, while critically analyzing current challenges such as structural heterogeneity, biosafety, mechanistic elucidation, and scalability. It highlights AI-guided design and pilot-scale validation as future directions. By linking fundamental chemistry and core mechanism to practical performance, this review offers a comprehensive roadmap for the rational design and scalable deployment of next-generation lignin-based antimicrobial and antioxidant nanomaterials, promoting the transition toward sustainable bioresource valorization. • LANs emerge as a promising candidate for the next-generation sustainable antimicrobial and antioxidant nanomaterials. • The structure−property−performance relationships and antimicrobial mechanisms of LANs were examined systematically. • Strategies for reinforcing lignin's antibacterial and antioxidant efficacy were evaluated critically. • Solutions to overcome existing challenges were proposed.