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 cultures. The hydrogels’ matrix comprises a viscoelastic alginate primary network, interpenetrated by a secondary network formed by the neural 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 400 µm thick hydrogels 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 the 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 80 charging/discharging cycles and remaining structurally and functionally stable under cell culture conditions for over four weeks. Cortical neuron cultures derived from human induced pluripotent stem cells prove the stability and cytocompatibility of our proposed hydrogels for over 28 days in culture. Collectively, these results highlight the potential of electrically active hydrogels loaded with PEDOT:PSS as soft, bioelectronic interfaces for neural engineering applications. ... Read more

Bioelectronics is a rapidly evolving interdisciplinary field that integrates principles of electrical engineering, materials science, and biology to develop electronic interfaces capable of recording and stimulating biological activity of the human body. The conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has emerged as a key bioelectronic material due to its unique properties, processing versatility, and biocompatibility. This work provides an overview of PEDOT:PSS-based bioelectronic interfaces and their growing potential in clinical applications. The historical development of PEDOT:PSS is first traced, highlighting its rise as one of the most successful materials in organic bioelectronics. The fundamental properties that make PEDOT:PSS particularly well-suited for bioelectronic interfaces are then examined, with a focus on how these properties can be precisely tuned through advanced processing and fabrication techniques. Both well-established micropatterned interfaces and the latest advancements in multidimensional hydrogel-based structures are discussed. Finally, cutting-edge clinical applications of bioelectronic systems that incorporate PEDOT:PSS are discussed, underscoring their potential in next-generation medical technologies. Overall, this work presents a balanced and forward-looking perspective that connects the evolution of PEDOT:PSS to its emerging role in clinically translatable bioelectronic systems. ... Read more