We developed a versatile mid-infrared photothermal (MIP) modality that enabled study of metabolic activities in living cells coupled with stable isotope probing. Performance of laser and light emitting diode were compared and system detection limit was demonstrated for different stable isotope probes. We treated the cancer and bacteria cells with deuterium, 13C and 15N labelled nutrients, and acquired the multi-spectral images with the MIP microscope. We observed the red shift in the infrared spectrum, indicating the incorporation of heavy atoms into cell metabolism. Sub-cellular spatial distribution of metabolites including carbohydrates, nucleic acids, proteins and lipids were profiled with high chemical specificity, sub-micrometer spatial resolution and high throughput.
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