(738f) Interaction of Eugenol and Novel Lignin Grafted Silica Nanoparticles with Synthetic Lipid Bilayers

Authors: 
Moradipour, M., University of Kentucky
Chase, E., University of Tennessee Chattanooga
Khan, M. A., University of Kentucky
Asare, S. O., University of Kentucky
Lynn, B. C., University of Kentucky
Rankin, S. E., University of Kentucky
Knutson, B. L., University of Kentucky
Lignin oligomers have broadly been recognized as a potential source of renewable aromatics for advanced materials, with a goal of developing functionalized surfaces with desirable selectivity (for separations), antimicrobial, and antifouling properties. Surface modification with lignin components also allows the quantification of interactions between lignin oligomers with solutes and biomolecules for the development of structure-surface property relationships. The potential to translate the properties of small-lignin derived molecules to surfaces has been limited due to the lack of well defined lignin oligomers. With the availability of lignin oligomers of known chemistry synthesized through a “building up” approach, this work develops and validates a generalizable approach to the functionalization of surfaces with lignin oligomers using versatile click chemistry. Here, allyl-modified guaiacyl β-O-4 guaiacyl (GG) lignin dimer is synthesized and attached to mesoporous silica nanoparticles (MSNPs) via click chemistry. The ability of GG lignin-dimer functionalized particles to interact with and disrupt synthetic lipid bilayers is compared to MSNPs functionalized with allyl group containing eugenol (l-hydroxy-2-methoxy-4-allylbenzene), a known natural antimicrobial. Uniform MSNPs were synthesized, and post-synthesis thiol attachment (SH) using (3 mercaptopropyl) trimethoxysilane (MPTMS) was quantified by Ellman’s test. The resultant SH-MSNPs were conjugated with GG lignin dimers and eugenol separately by a thiol-ene reaction under ultraviolet light in presence of a photo initiator. Thermogravimetric analysis (TGA) was used to determine that approximately 0.22 mmol of eugenol and 0.16 mmol of the GG dimer were attached to every 1 gram of the MSNPs. The interaction of the functionalized MSNPs with a model phospholipid bilayer of 1,2-Dipalmitoyl-sn-Glycero-3-Phosphocholine (DPPC) (representing cell membranes) supported on gold surface was investigated using a Quartz Crystal Microbalance with Dissipation (QCM-D). While eugenol-grafted particles in PBS (0.5 mg/mL) were found to be benign and nondestructive to the structure of the bilayer interpreted from slight changes in the mass on the QCM-D sensor after exposure of the bilayer to the particles, dimer attached particles with the same concentration caused considerable lipid mass loss associated with disruption of some of the membrane, suggesting higher biocidal activity. This suggests the potential for the functionalization of nanoparticles with specific lignin oligomers to be a path to novel bio-inspired materials and provide a usage for lignin building blocks recovered from lignin deconstruction.