Functional drug screening of tumor organoids on an active-matrix digital microfluidic chip for cancer precision medicine

Cancer is a leading global cause of morbidity and mortality, with inter- and intra-tumor heterogeneity contributing to suboptimal therapeutic outcomes. While genomic profiling has advanced precision oncology, many tumors lack targetable mutations, underscoring the need for functional assays. Here, we present a drug sensitivity testing platform for patient-derived organoids (PDOs) based on active-matrix digital microfluidics (AM-DMF). The system comprises a microfluidic timing-control board (<50 ms switching precision), a temperature-regulation module (37 ± 0.3 °C) and an integrated imaging module for multiscale visualization. Droplet generation, transport, mixing, and dilution on the AM-DMF platform are programmably controlled via electrowetting-on-dielectric (EWOD) actuation, with volume stability from 1 to 100 nL per droplet (CV < 3%). A multilayer design of the AM-DMF chips suppressed crosstalk and leakage current, enabling stable operation over 10 h. PDO-loaded droplets were efficiently generated through symmetric "one-to-two" splitting, achieving >71% success within 4-5 tearing cycles. Evaluation of cisplatin cytotoxicity across multiple PDOs on AM-DMF chips revealed time- and dose-dependent responses, including early morphological contraction (12 h) and subsequent structural disintegration (72 h) at high concentrations. Live/dead staining confirmed membrane damage under high-dose treatment, reflected by increased red fluorescence. Quantitative analysis demonstrated consistent dose-dependent inhibition of viability across all PDOs. Notably, on-chip measurements showed response trends consistent with conventional 96-well plate assays, yet with moderately higher inhibition rates, indicating enhanced assay sensitivity. Overall, we have developed an automated, high-throughput drug-testing system for PDOs, wherein the entire workflow, including organoid culture, precise drug concentration gradient generation, multi-dose drug screening, staining, and imaging, was seamlessly integrated and performed on a single active-matrix digital microfluidics chip. Collectively, this integrated AM-DMF platform offers a systematic, scalable strategy for functional precision medicine, especially suited to scarce clinical specimens and complex multidrug regimens.