Lignin is a phenolic cell wall polymer that remains as a waste product after lignocellulosic biomass is converted to fermentable sugars that can be used for the production of fuels and chemicals. Development of high-value co-products from this waste stream is expected to make the production of fuels and chemicals from biomass economically more viable. We have developed lignin-based nanotubes synthesized in an alumina membrane template. Specifically, isolated lignin was linked to the inner walls of activated alumina membranes and then layers of dehydrogenation polymer were added onto the base layer and were crosslinked via a peroxidase-catalyzed reaction. The lignin nanotubes were released by dissolving alumina membrane in dilute phosphoric acid. By using phenolic monomers displaying different reactivities, we were able to change the thickness of the polymer layer deposited within the pores, resulting in the synthesis of nanotubes with a wall thickness of approximately 45 nm or nanowires with a nominal diameter of 200 nm. SEM and nano-indentation studies indicated that the nanotubes exhibit different morphology and mechanical properties depending on the biomass species (hardwood, softwood, grass) and lignin isolation procedure. Based on cytotoxicity experiments with human cell line (HeLa cells), lignin nanotubes have lower cytotoxicity than multi-walled carbon nanotubes. Furthermore, lignin nanotubes enable the uptake of DNA, as shown by the expression of green fluorescent protein (GFP) following transfection with plasmid DNA. The ease with which lignin nanotubes can be functionalized makes them attractive candidates for the delivery of DNA in gene therapy, as well as for the smart delivery of pharmacological agents. Funding of this project is provided by USDA-Biomass Research & Development Initiative project 2011-10006-303508.

Development of lignin nanotubes for the smart delivery of therapeutic agents

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.