Real-Time Impedimetric Monitoring of 3D Cancer Spheroids Using a PDA-Functionalized Microelectrode Platform Integrated with Graphene Quantum Dot-Based Nanocomposites

We describe a bioelectronic interface that combines indium tin oxide (ITO) microelectrode integrated with polydimethylsiloxane (PDMS) microwells to allow real-time monitoring of tumor responses in three dimensions (3D). This design combines PDMS microwells with an ITO microelectrode array that has been improved by polydopamine (PDA) polymerization to make it more biocompatible. The present study employed a unique nanocomposite, Cryptotanshinone (CPT) conjugated to graphene quantum dots (GQDs), exhibiting remarkable anticancer characteristics. The stability and targeted distribution of CPT were significantly enhanced by GQDs, hence amplifying its antiproliferative actions. Real-time resistance measurements revealed substantial differences in the half-maximal inhibitory concentrations (IC₅₀) of the two-dimensional (2D) and 3D cancer models, with values of 0.62 ± 0.14 and 1.47 ± 0.16 μg/mL, respectively. Comprehensive materials characterization and biological validation through gene expression and flow cytometry confirmed the platform's reliability. This materials-centric approach establishes a robust interface between biological systems and electronic monitoring, offering possibilities for drug screening applications.