Synthesis and Characterization of Eco-Friendly Lignin Nanoparticles for Antimicrobial and UV Barrier Applications in Textiles and Possible Sunscreen Formulations

Lignin nanoparticles (LNPs) present a promising alternative owing to several beneficial characteristics as compared to conventional metal and other nanoparticles. They are cost-effective, eco-friendly, biocompatible, and biodegradable. This study aimed to synthesize and characterize LNP-based antimicrobial and ultraviolet (UV) barrier textiles, alongside a novel antimicrobial UV-barrier sunscreen formulation. LNPs were synthesized via acid precipitation, and the particle size and morphology characterized through scanning electron microscopy (SEM). The antimicrobial efficacy and UV shielding properties of the LNPs were quantitatively assessed using spectrophotometric methods. LNPs range from 70 nm to 200 nm as observed under SEM analysis and also showed the presence of LNPs on the cotton cloth. Both LNPs and LNPs containing cloth demonstrated antimicrobial properties against tested bacterial (E. coli and P. aeruginosa) and fungal (Aspergillus niger and Penicillium sp.) strains. LNPs demonstrate minimum inhibitory concentration of 1.5 mg/mL against E. coli. The distinctive properties of LNPs, specifically their antimicrobial, and UV barrier capabilities, position them as promising candidates for applications. Thus, LNPs offer eco-friendly, UV-protective, and antimicrobial properties, enhancing sustainability in textiles and also in skincare by providing natural antioxidants and UV shielding.