Micropillar-Based Biosensor for Monitoring Contamination- and Compound-Induced Metabolic States in Cell Cultures

Ensuring the quality, safety, and functional performance of stem cell cultures remains a critical challenge in biomedical research, drug development, and emerging cell-based therapies, as early metabolic disturbances can compromise outcomes and therapeutic efficacy. Glucose (Glu) consumption and L-lactate (LA) production serve as central indicators of cellular bioenergetic state, stress, and viability. However, conventional analytical approaches rely on discontinuous, labor-intensive assays that disrupt workflows and limit early intervention. Here, we report a miniaturized electrochemical biosensing platform for serial time-resolved analysis of Glu and LA in human induced pluripotent stem cell (hiPSC) culture media using a micropillar array (MPA)-based microfluidic electrochemical device (MED). The device exhibits linear detection ranges of 0.5-35 mM for Glu and 0.5-40 mM for LA, with limits of detection (LODs) of 0.18 ± 0.01 mM and 0.19 ± 0.01 mM, respectively. Using serially collected culture media, the MED quantifies dose-dependent metabolic responses to mitochondrial inhibition with oligomycin, revealing suppressed metabolic turnover and altered Glu-LA coupling prior to observable morphological changes. By enabling paired metabolic readouts from small-volume, undiluted culture-media samples, this platform provides a practical analytical route toward earlier recognition of culture-state deviations and more informed monitoring of stem-cell culture quality and drug-induced metabolic responses.