Preparation and application of lignin nanoparticles: a review

Lignin is a natural renewable biopolymer with abundant reserves and great potential. As a by-product of the pulp and paper industry, the world can produce 150 billion tons of it every year, but it has not been effectively utilized. It was found that disordered and complex lignin can be converted into ordered and homogeneous nanoparticles by self-assembly, solvent exchange and acid precipitation. Lignin nanoparticles (LNPs) have the advantages of high stability, high activity, good biocompatibility and biodegradability, as well as improved structural and size control, antioxidant activity and other properties. LNPs have great potential for application not only as a natural alternative to traditional petroleum derivatives, biopharmaceutical carriers, but also in hydrogels. In recent years, the research of LNPs has received a lot of attention. It is hoped that more economical, environmentally friendly and high yielding methods for the synthesis of LNPs will be investigated in the future. This paper reviews the preparation methods of LNPs and their applications in various fields.