In-situ monitoring of cellular H₂O₂ within 3D cell clusters using conductive scaffolds

Accurately monitoring H₂O₂ concentrations in 3D cell clusters is challenging due to limited diffusion and rapid degradation of H₂O₂ in the culture medium. Despite the incorporation of three-dimensional cell culture approaches, the detection technology has largely remained as a 2D planar system. In this study, we present a versatile approach of 3D electrochemical sensing utilizing carbon nanotubes as conductive scaffolds for in-situ monitoring of H₂O₂ in cell clusters. These scaffolds enabled direct contact between H₂O₂ released from cells and the electrodes, thereby improving sensitivity and ensuring biocompatibility for cell aggregates. The scaffolds exhibited electrocatalytic behavior with a limit of detection of 6.7 nM H₂O₂. Additionally, the electrochemical responses of cell clusters with the scaffolds exhibited significantly higher current compared to clusters without scaffolds when stimulated with model drugs. This study underscores the potential of conductive scaffolds for real-time monitoring of H₂O₂ released from cell clusters in 3D microenvironments.