Amphiphilic
gold core nanoparticles (AmNPs) striped with hydrophilic
11-mercapto-1-undecanesulfonate (MUS) and hydrophobic 1-octanethiol
(OT) ligands are promising candidates for drug carriers that passively
and nondisruptively enter cells. Yet, how they interact with cellular
membranes is still only partially understood. Herein, we use electrophysiology
and imaging to carefully assess changes in droplet interface bilayer
lipid membranes (DIBs) incurred by striped AmNPs added via microinjection.
We find that AmNPs spontaneously reduce the steady-state specific
capacitance and contact angle of phosphatidylcholine DIBs by amounts
dependent on the final NP concentration. These reductions, which are
greater for NPs with a higher % OT ligands and membranes containing
unsaturated lipids but negligible for MUS-only-coated NPs, reveal
that AmNPs passively embed in the interior of the bilayer where they
increase membrane thickness and lateral tension through disruption
of lipid packing. These results demonstrate the enhanced evaluation
of nano–bio interactions possible via electrophysiology and
imaging of DIBs.