(87c) Disruption of Tethered Lipid Bilayers by Silica-Core Nanoparticles: Effect of Surface Functional Group

Ying Liu, Quanxuan Zhang, Gregory L. Baker, Zhen Zhang, and R. Mark Worden

In this paper, we use present a method that uses a tethered bilayer lipid membrane (tBLM) to study the interaction of engineered nanomaterials (ENM) with biomembranes. Highly insulating tBLM were formed on gold electrodes using 1, 2-dipalmitoyl-sn-glycero-phosphothioethanol (DPPTE) to form the lower leaflet and 1, 2-dioleoyl-sn-glycero-phosphocholine (DOPC) to form the upper leaflet. The tBLM were then exposed to silica nanoparticles having different surface properties (unmodified, amine terminated, and carboxylic-acid terminated). Electrochemical impedance spectroscopy was used to measure time-dependent changes in the tBLM’s impedance following ENM exposure. The data were fit to an exponential model and then analyzed using a hierarchical clustering algorithm. The resulting dendrograms confirmed that ENM having different surface functional groups induced statistically different changes in tBLM impedance. The amine terminated ENM reduced tBLM impedance considerably faster than did the carboxylic-acid terminated and unmodified ENM.  Based on dynamic light scattering data, exposure to the tBLM triggered an increase in average particle size for the unmodified ENM but not the amine-terminated and unmodified ENM. Results of this study could provide insight into fundamental mechanisms by which ENM interact with biomembranes and may lead to high-throughput methods to assess the health risk of ENM based on their interactions with biomembranes.  

Keywords: tBLM; silica nanoparticles; electrochemical impedance spectroscopy; hierarchical clustering; lipid bilayer