Electrical Method to Quantify Nanoparticle Interaction with Lipid Bilayers

Randy P. Carney †, Yann Astier ‡, Tamara M. Carney†, Kislon Voïtchovsky †, Paulo H. Jacob Silva †, andFrancesco Stellacci †*

^† Institute of Materials, École Polytechnique Fédérale de Lausanne, EPFL-STI-IMX-SuNMIL, Lausanne CH-1015, Switzerland

^‡ ITQB, Universidade Nova de Lisboa, Avenida Da Republica, Oeiras, Portugal

ACS Nano, Article ASAP

DOI: 10.1021/nn3036304

Publication Date (Web): December 26, 2012

Copyright © 2012 American Chemical 

Understanding as well as rapidly screening the interaction of nanoparticles with cell membranes is of central importance for biological applications such as drug and gene delivery. Recently, we have shown that “striped” mixed-monolayer-coated gold nanoparticles spontaneously penetrate a variety of cell membranes through a passive pathway. Here, we report an electrical approach to screen and readily quantify the interaction between nanoparticles and bilayer lipid membranes. Membrane adsorption is monitored through the capacitive increase of suspended planar lipid membranes upon fusion with nanoparticles. We adopt a Langmuir isotherm model to characterize the adsorption of nanoparticles by bilayer lipid membranes and extract the partition coefficient, K, and the standard free energy gain by this spontaneous process, for a variety of sizes of cell-membrane-penetrating nanoparticles. We believe that the method presented here will be a useful qualitative and quantitative tool to determine nanoparticle interaction with lipid bilayers and consequently with cell membranes.