Imaging the disruption of phospholipid monolayer by protein-coated nanoparticles using ordering transitions of liquid crystals

We report an easily visualized liquid crystal (LC)-based system to study the molecular interactions between protein-coated gold nanoparticles (AuNPs) and supported phospholipid monolayer self-assembled at the aqueous-LC interface. Protein-coated AuNPs were found to disrupt the phospholipid monolayer and resulted in the orientational transitions of LCs that support the phospholipid layer. The disruption of the phospholipid monolayer depends on the type of protein (albumin, neutravidin, and fibrinogen) adsorbing onto nanoparticles. Furthermore, our results suggest that hydrophobic interaction plays a major role in the disruption of the phospholipid layer by protein-coated AuNPs. Results obtained from this study may offer new understanding in the potential cytotoxicity of nanomaterials, where the interaction between nanoparticles and cell membrane is an important step. (C) 2008 Elsevier Ltd. All rights reserved.