Reproducible High‐Impedance Supported Lipid Bilayers on PEDOT:PSS

Abstract

ABSTRACT Supported lipid bilayer (SLB) sensing platforms are a promising, versatile technology for studying native cell membrane processes and enabling applications harnessing them. Forming SLBs on conductive polymers such as poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) allows the use of electrochemical impedance spectroscopy (EIS) as a rapid, sensitive technique to probe dynamic membrane interactions. However, since these biosensors require large impedances to measure biological signals, their applicability is limited by difficulties in reproducing high‐impedance bilayers. This challenge is compounded by the need to controllably functionalize the electrode using hydrophilic treatments (e.g., oxygen plasma). This study develops a protocol for reproducible high‐impedance bilayers by investigating how oxygen plasma‐treating PEDOT:PSS influences SLB formation. Excessive plasma treatment is shown to hinder SLB formation by creating an unstable PEDOT:PSS surface in water. By controlling parameters affecting SLB formation, resistances of up to 5.9 kΩ cm 2 for 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (POPC) and 31 kΩ cm 2 for a 4:1 mixture of 1,2‐dioleoyl‐sn‐glycero‐3‐phosphocholine (DOPC) and 1,2‐dioleoyl‐3‐trimethylammonium‐propane (DOTAP) SLBs are achieved. At least one electrode per chip exceeds 25 and 1000 Ω cm 2 with corresponding surface coverages of 96% and 99.9% for these lipid compositions, respectively, demonstrating a 100% yield of chips and highlighting the protocol's potential for advancing SLB‐based biosensors.