Metabolic Activity Phenotyping of Single Cells with Multiplexed Vibrational Probes

Quantitative measurements of metabolic activities of individual cells are essential to understanding questions in diverse fields in biology. To address this challenge, we present a method, termed metabolic activity phenotyping (MAP), to probe metabolic fluxes by utilizing multiplexed vibrational metabolic probes. With specifically designed single-whole-cell confocal micro-Raman spectroscopy, quantitative measurement of lipid and protein synthesis activity was achieved with high throughput (several orders of magnitude improvement over a commercial confocal system). In addition, metabolic heterogeneity upon various drug treatments was also revealed and evaluated at the single-cell level. We further demonstrated that MAP was more robust than the label-free Raman methods and was able to make the correct classification among diverse cancer types and breast cancer subtypes by exploring the dimension of metabolism. The capability of MAP to explore metabolic profiles at the single-cell level makes it a valuable tool for basic single-cell studies as well as other screening applications.