Simultaneous Monitoring of Intracellular Glucose and Extracellular Lactate in Single Cells to Assess Cell Tumorigenicity

Metabolites play a critical role in cellular functions and environmental interactions. Herein, we developed an electrochemical platform for simultaneous detection of intracellular glucose and extracellular lactate in single cells to assess cell tumorigenicity, addressing the limitation of "internal-external separation" in traditional techniques. A microwell array chip enabled high-efficiency single-cell capture (93.75%), while glucose oxidase (GOx)-functionalized nanopipettes achieved nondestructive intracellular glucose detection via ion transport electrochemistry, with a linear range of 0.1-10 mM and a detection limit of 0.03 mM. Extracellular lactate was quantified using lactate oxidase@zeolitic imidazolate framework-8 (LOx@ZIF-8) nanoparticles combined with electrochemiluminescence (ECL) imaging, showing a linear response from 1 to 50 μM (<i>R</i>² = 0.9977). Receiver Operating Characteristic (ROC) analysis showed that the combination of glucose and lactate detection achieved complete separation of normal cells (MCF-10A) from tumor cells (MCF-7) and improved the classification of tumor subtypes (MCF-7 and MDA-MB-231), highlighting the advantages of dual-mode metabolite detection in single-cell analysis. Dynamic monitoring revealed that inhibiting lactate efflux with AR-C155858 reduced chemoresistance in MDA-MB-231 cells, linking lactate secretion to tumor malignancy. This dual-modal approach provides a powerful tool for single-cell metabolic profiling and early cancer diagnosis.