The research team at the University of Washington’s McKelvey School of Engineering has invented an injectable, moldable, and 3D printed conductive granular hydrogel. The goal is to replace rigid implants made of metal or silicon with soft, body-like electrodes that can measure and stimulate biological signals. The related research findings were published on October 8 in the journal Small.
The team, led by Alexandra Lutz, synthesized spherical micro-particles using the conductive polymer PEDOT:PSS. When these particles are densely packed, they behave like a paste-like, micro-porous material: they can flow through a needle or printing nozzle under shear force; once the load is removed, they re-establish contact and form a size-stable composite material.
The temporary contact points between the particles create micron-sized pores, allowing for a reversible transition between the flowing and solid states. In printing tests, continuous filaments that conform to complex surfaces can be produced. Functional validation was completed in Barani Raman’s laboratory, where the particles were placed at the tips of locust antennae, recording local electric field potentials during olfactory stimulation.
Lutz and Gostenkors have applied for a U.S. patent for the manufacturing and application of these particles, and they are working with the university’s technology management office to address issues of rights protection and the transition of these technologies into practical applications.