A Versatile Photoelectrochemical Nanopipette Platform for In Situ Profiling of Intracellular Metabolites

Abstract Monitoring intracellular metabolites in situ at the single-cell level is essential for understanding cellular heterogeneity and metabolic dynamics. However, adaptable sensing platforms for diverse intracellular metabolites remain limited as different recognition reactions often require tailored integration with interfacial architectures and signal-transduction processes. Herein, we report a versatile photoelectrochemical (PEC) single-cell nanotool for versatile intracellular metabolites. The sensing interface was fabricated by sequentially modifying the outer wall of the nanopipette with a self-assembled gold film, a titanium dioxide nanolayer, and specific dehydrogenase enzymes. Leveraging the biocatalytic interconversion between NAD+ and NADH, this modular design enables facile adaptation toward different metabolites by simply replacing the corresponding dehydrogenase, as demonstrated by the sensitive and selective detection of glucose, lactate, and d-2-hydroxyglutarate. More importantly, with micromanipulator guidance, the engineered nanotool achieved in situ PEC profiling of intracellular metabolites at the single-cell level, providing insights into cellular heterogeneity and metabolic dynamics. This versatile sensing strategy provides a facile and expandable platform for single-cell metabolite analysis and holds great potential for applications in cellular metabolism studies, disease diagnostics, and precision biomedical research.