Electrically Active Hydrogels Based on PEDOT:PSS for Neural Cultures

Abstract

Electrically active hydrogels are attracting significant interest as biohybrid materials for electrical interfacing with biological tissues. Here, we report the development of electrically active hydrogels, specifically engineered for in vitro neural cell culture applications. The hydrogels’ matrix comprises a viscoelastic alginate primary network, interpenetrated by a secondary network formed by a cell-adhesive protein, laminin. Conducting poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) particles are embedded throughout the hydrogel matrix, serving as the electrically active filler phase. Oscillatory rheology confirmed the viscoelastic nature of the composite hydrogels, with storage and loss moduli in the range of 1–10 kPa, suitable for neural tissue interfacing. The hydrogels exhibited high optical transparency across the visible spectrum. At a wavelength of 500 nm, transmission exceeded 45% for hydrogels 400 μm thick, and was further enhanced to over 60% by reducing the hydrogel thickness to 150 μm. We established a reproducible protocol for electrochemical impedance spectroscopy and cyclic voltammetry measurements, demonstrating that incorporation of PEDOT:PSS significantly enhanced both conductivity and charge storage capacitance of hydrogel films. The Alginate-Laminin-PEDOT:PSS hydrogels demonstrated excellent operational stability, maintaining consistent electrochemical performance over 100 charging/discharging cycles and remaining structurally and functionally stable under cell culture conditions for over two weeks. The cytocompatibility of the hydrogels was proven by culturing SH-SY5Y neural progenitor cells alongside hydrogel constructs for more than 7 days. Collectively, these results highlight the potential of electrically active hydrogels loaded with PEDOT:PSS as soft, bioelectronic interfaces for neural engineering applications.