Lithography-Free Water Stable Conductive Polymer Nanowires

Free-standing nanowires can gain intracellular access without causing stress or apoptosis. Current approaches to generate nanowires focus on lithographic patterning and inorganic materials (Si, GaAs, Al₂O₃, etc.) while organic materials are less explored. Use of organic conductive polymers allows for the creation of soft mixed ion–electron conducting nanowires. Processing conductive polymers into nanowires is challenging due to the harsh chemicals and processing conditions used. Here, we demonstrate a lithography-free and scalable method to generate all-organic, water-stable nanowires composed of conductive polymers. A nanoporous membrane is filled with conductive polymer in solution, followed by a cross-linking step to make the polymer water stable. The surface of the membrane is anisotropically etched using a reactive ion etcher to reveal the polymer inside the pores, which extends from the membrane as nanowires. We interface the nanowires with model algal cells and human primary hematopoietic stem and progenitor cells.