Lignin-based materials for drug and gene delivery

As the most abundant natural polyphenol compounds, lignin is generally regarded as byproducts of pulp and paper industry. With comprehensive studies being performed to investigate the structure and chemistry of lignin, many inherent and unique properties have been gradually discovered, including antioxidant activities, antimicrobial activities, biocompatibilities, optical properties, metal ions chelating, and redox activities. On the other hand, with the development of materials science, different forms of materials, such as nanoparticles, hydrogels, and films, can be fabricated from lignin. Therefore, the development of lignin-based biomedical materials is one of the most promising applications of lignin resources. As the major aspect of the biomedical application, more and more studies are reported on the lignin-based materials for drug and gene delivery. Here, we describe different kinds of lignin-based materials that can be used as carriers, excipients, and fillers in drug delivery and gene delivery vehicles and bioimaging for biomedical applications.