Solution-processed Ti3C2Tx MXene coatings for three-dimensional microelectrodes in label-free single-cell impedance spectroscopy

Abstract

Three-dimensional (3D) microelectrodes may improve electric-field coupling to confined cells, but their fabrication often requires complex metallization or specialized equipment. Here, we decouple topography formation from conductive functionalization by combining solvent-induced swelling of cyclic olefin copolymer (COC) with solution-processed Ti3C2Tx MXene (TMX) coating. Swelling generated COC features approximately 10 μm high, while spin-coated TMX formed an approximately 80 nm conformal conductive layer. The electrodes were integrated into a constriction-based microfluidic device and compared with 3D Au electrodes fabricated on the same swollen COC architecture. Simulations showed field localization across the constriction for both materials. Replicated differential impedance measurements of more than 20 individually trapped MDA-MB-231 cells per material, using three independently fabricated devices per material, showed increased low-frequency impedance relative to cell-free medium. Although Au produced smoother spectra and stronger absolute separation, TMX generated measurable cell-associated responses, demonstrating a solution-processable route to 3D microfluidic bioelectrodes for label-free single-cell sensing.

Abstract as supplied by the indexing source. © the authors / publisher.