U20 - PEDOT:PSS-Based Platform for Long-Term Electric Stimulation in 3D Cell Culture

Friday, October 10, 2025

10:00 AM - 11:00 AM PDT

Location: Exhibit Hall F, G & H

Presenting Author(s)

Seongwoo Lee

Master Course Student
Korea Advanced Institute of Science and Technology
Daejeon, Taejon-jikhalsi, Republic of Korea

Co-Author(s)

EK

Eunmin Ko

Ph.D. graduate
Korea Advanced Institute of Science and Technology, United States
Uk Jegal

a Ph.D. student
Korea advanced institute for science and technology (KAIST)
Daejeon Metropolitan City, United States

Last Author(s)

Jennifer H. Shin

Professor
KAIST
Daejeon, Republic of Korea

Introduction: : Bioelectric signals significantly influence tumor progression, particularly in breast cancer, by regulating cell migration, proliferation, and differentiation. A notable example is ductal carcinoma in situ (DCIS), where malignant cells proliferate within the lumen of the mammary duct. This compartment is characterized by a trans-epithelial potential (TEP), an electrochemical gradient generated by the polarized luminal epithelium. TEP induces depolarization in luminal epithelial cells, a bioelectric state associated with increased mitotic activity and early tumor expansion.
Despite increasing recognition of these physiological electrical cues, conventional electric stimulation platforms—primarily designed for two-dimensional (2D) cell cultures and employing metallic electrodes or agar salt bridges—pose substantial limitations. In particular, metallic probes often cause ion leaching, electrolyte imbalance, and local pH shifts during stimulation, making long-term, stable organoid culture impractical. These include ion leaching, low biocompatibility, and poor control over stimulation parameters, all of which compromise the viability and relevance of three-dimensional (3D) culture systems such as tumor organoids.
To address these issues, we developed a biocompatible and programmable electric stimulation platform by coating electrospun poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) fiber sheets with poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS). The resulting flexible electrodes enabled the stable and long-term delivery of low-amplitude alternating current (AC) fields in hydrogel-based 3D cultures. Using this platform, we investigated how such fields modulate the phenotype and growth behavior of breast cancer organoids, simulating physiological TEP conditions in vitro. Our results suggest that controlled electric stimulation may offer a new strategy for understanding and influencing breast cancer development in a biologically relevant setting.

Materials and

Methods: : To construct a biocompatible and programmable electric stimulation platform suitable for 3D culture, we fabricated flexible electrodes by electrospinning poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) into fibrous mats, followed by dip-coating with poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS). The resulting conductive sheets were integrated into a custom-designed chamber compatible with hydrogel-based culture systems. To further improve electric field uniformity in 3D culture environments, the PEDOT:PSS-coated P(VDF-TrFE) films were folded into vertical-wall configurations and integrated on opposing sides of the chamber (Fig. 1(a)).
Breast cancer organoids were formed by embedding triple-negative breast cancer (TNBC) cells, specifically SNU-1581, into basement membrane extract (BME) domes. For each well, 3 × 10⁴ cells were suspended in 40 μL of BME and seeded to form domes (Fig. 1(a)).
Electric stimulation was delivered using a signal generator connected to the PEDOT: PSS electrodes, allowing for fine control over amplitude, frequency, and waveform. In this study, low-amplitude alternating current (AC) fields (e.g., 50 mV/cm, 1Hz) were applied continuously for up to 7 days during organoid formation and maturation. Throughout the stimulation period, the growth and morphology of organoids were monitored using bright-field microscopy. Cytocompatibility of the electrodes was assessed using live/dead staining and epithelial sheet cultures. Additional resistance and electrical stability measurements were conducted using a source meter to ensure long-term reliability of the device under physiological conditions.

Results, Conclusions, and Discussions:: Our study investigates the modulation of 3D breast cancer organoid growth using low-amplitude alternating current (AC) electric fields (EFs) delivered via a novel electrode system. We developed PEDOT:PSS-coated P(VDF-TrFE) electrodes which, quantified by four-point probe measurements, exhibited significantly lower sheet resistance (55.7 Ω/sq) compared to PEDOT-only films (100.2 Ω/sq). This enhanced conductivity is attributed to the conformal interface of the electrospun fiber structure, which improves polymer packing and facilitates charge transport.

The electrodes demonstrated excellent cytocompatibility under electrical stimulation. Epithelial cells cultured on the electrodes showed consistently high viability and preserved an intact sheet morphology after extended exposure, indicating minimal electrochemical stress. In contrast, conventional platinum electrodes induced noticeable cytotoxicity, likely due to ion leaching and electrochemical byproducts.

Applying a low-amplitude AC field (63 mV/cm) for 7 days to SNU-1581-derived triple-negative breast cancer organoids resulted in accelerated growth. Stimulated organoids showed increased size, denser cellular packing, and smoother boundaries compared to non-stimulated controls. These morphological changes suggest that EF exposure enhances self-organization and proliferation during early organoid formation, with no evidence of structural disruption or viability loss, confirming the biological safety of the stimulation parameters.

These preliminary findings indicate that weak AC electric fields, delivered via a biocompatible PEDOT:PSS system, can modulate breast cancer organoid growth in 3D culture. This outcome supports the hypothesis that bioelectric signaling influences epithelial tumor architecture, particularly in early growth phases. Our approach mimics the endogenous bioelectric gradients, such as the trans-epithelial potential (TEP), found in the microenvironment of ductal carcinoma in situ (DCIS). The enhanced organoid growth likely reflects how such bioelectric cues regulate cellular organization and proliferation within confined luminal spaces. This work provides a foundation for further exploration into EF-guided tumor modeling and the broader application of programmable electrostimulation in cancer research.

Acknowledgements and/or References (Optional): : This research was supported by a grant of the Korea-US Collaborative Research Fund(KUCRF), funded by the Ministry of Science and ICT and the Ministry of Health & Welfare, Republic of Korea (grant number: RS-2024-00468873)

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