In recent years, lignin has drawn increasing attention for different applications due to its intrinsic antibacterial and antioxidant properties, coupled with biodegradability and biocompatibility. However, chemical modification or combination with metals is usually required to increase its antimicrobial functionality and produce biobased added-value materials for applications wherein bacterial growth should be avoided, such as biomedical and food industries. In this work, a sonoenzymatic approach for the simultaneous functionalization and nanotransformation of lignin to prepare metal-free antibacterial phenolated lignin nanoparticles (PheLigNPs) is developed. The grafting of tannic acid, a natural phenolic compound, onto lignin was achieved by an environmentally friendly approach using laccase oxidation upon the application of high-intensity ultrasound to rearrange lignin into NPs. PheLigNPs presented higher antibacterial activity than nonfunctionalized LigNPs and phenolated lignin in the bulk form, indicating the contribution of both the phenolic content and the nanosize to the antibacterial activity. Studies on the antibacterial mode of action showed that bacteria in contact with the functionalized NPs presented decreased metabolic activity and high levels of reactive oxygen species (ROS). Moreover, PheLigNPs demonstrated affinity to the bacterial surface and the ability to cause membrane destabilization. Antimicrobial resistance studies showed that the NPs did not induce resistance in pathogenic bacteria, unlike traditional antibiotics.
|Number of pages||10|
|Journal||ACS applied materials & interfaces|
|State||Published - 24 Aug 2022|
Bibliographical noteFunding Information:
This work was supported by European Project Reinvent H2020-BBI-JTI-2017 (Bio-Based Industries), Grant Agreement Number 792049, and the European Project Biomat H2020-NMBP-TO-IND-2018–2020, Grant Agreement Number 953270. A.G.M. acknowledges Agència de Gestió d’Ajuts Universitaris i de Recerca (Generalitat de Catalunya) for providing her with a PhD grant (2019FI_B 01004).
© 2022 American Chemical Society. All rights reserved.
- antimicrobial resistance
- enzymatic grafting