Development of magnetic lignin nanoparticles from low-molecular-weight eucalyptus and spruce lignin fractions

Abstract: Lignin is one of the most common biopolymers in the world. Together with cellulose andhemicellulose it constitutes the fibers in the wood. It has a high molecular weight due to its complexstructure consisting of crossed-linked phenolic monomers and is concatenated with different types ofcarbon and ether bonds.In pulping processes, lignin is extracted in large quantities and used on site to produce energy for milloperations but is also removed as a waste product. This enables a product with high resources andaccessibility due to lignin's diverse properties. Therefore, lignin has the potential to be utilized inhigher value applications such as polymer materials, as well as a source of platform chemicals. Atpresent, the value applications of lignin are promising as additives for different kinds of productssuch as emulsifiers and especially as biofuel due to lignin's high carbon content.New technologies for development for utilization lignin are emerging for different kinds ofapplications due to lignin’s biocompatibility. The possibilities of lignin combined with existingresearch of nanotechnology gives opportunities to improve biomedical applications. By designinglignin derived nanoparticles with incorporated magnetic materials, the NPs obtainsuperparamagnetic properties which can be utilized for target drug delivery. This could be promisingagainst intractable cancer such as pancreatic cancer.This report presents a protocol for developing magnetic lignin nanoparticles from the lowestmolecular weight kraft lignin fractions of eucalyptus (hardwood) and spruce (softwood). By a methodof self-assembly, particles with a doughnut and core-shell morphology, as indicated by SEM and TEM,were yielded with a 10-50μL content of water-stabilized magnetite. The particle size distribution andzeta potential were determined by DLS and the possibility of the particles being suitable forbiomedical applications was discussed.