An Electrostatic Method for 3D Extrusion of Micron‐Sized Conductive Structures for Sensing Applications

Materials with high electrical conductivity and large specific surface area are essential for biosensing, as they enable efficient charge transfer and enhanced performance. We present near‐collector electroprinting, an electrostatic additive manufacturing technique for fabricating sub‐millimeter biosensor structures with high surface area, improved conductivity, and feature sizes reduced by orders of magnitude. PEDOT:PSS was used as the base ink material, and Ti 3 C 2 MXene was added to improve the electrical conductivity. The optimized ink achieved a conductivity of ∼117 S cm −1 . Using a nozzle with an inner diameter of 80 µm and optimized printing parameters enabled precise fabrication of well‐defined multilayer structures. Separate lines were printed at 40 µm pitch, with top‐layer fiber widths as small as 3 µm, demonstrating significant resolution enhancement relative to the nozzle size. The technique also enabled fabrication of solid structures at 30 µm pitch. Ink flow was evaluated over printing speeds of 0.5–4.5 mm s −1 to identify instabilities and back‐pressure effects. Functionality of the printed structures was assessed through protein attachment and release. Bovine serum albumin (BSA) release reached ∼198 ± 45 µg mL −1 , nearly a 107 ± 24% molar ratio relative to dextran sulfate. These results demonstrate strong potential for compact, high‐resolution biosensing applications with efficient biomolecule interaction.