Lignin nanoparticles as vehicles for transport and active release of hydrophobic actives

Spherical lignin particles offer a versatile platform for the development of advanced materials based on renewable resources. When their production can be coupled to simple protocols such as sonochemistry or innocuous solvent-antisolvent protocols, they become suitable tools for a wide range of biomedical and cosmetic applictions. Here, we describe generation of lignin nanoparticles in a flexible approach that additionally allows for the incorporation of actives. For such applications, another prerequisite is to use lignins with high purity, well-suited organoleptic quality, and biocompatibility. Following these criteria, a novel type of lignin nanoparticles (LNPs) was developed in a solvent-antisolvent approach. Their structural stability profile was investigated, as well as their ability to carry highly hydrophobic actives and release them in a pH-dependent manner. The application of antioxidative lignin particles as carriers for anti-inflammatory drugs is also expected to offer synergistic effects in vivo. Extensive insights into the growth mechanism are presented, that allows fine-tuning for specific applications, and the development of a general formation strategy. Characteristics of the LNPs generated by the the solvent-antisolvent approach are compared to those obtained by using sonochemistry.