Infrared microscopy of the biochemistry and metabolism in single living eukaryotic cells

The turn of the millennium has seen a growing interest in the study of live cells by infrared (IR) spectroscopy, driven by the versatility, wealth of molecular information, and potential for high-throughput screening offered by the technique. Measurements on individual cells, either isolated or within a multi-cellular structure, provide information that is not available from ensemble samples. The present review discusses the use of infrared (IR) microscopy to analyse live single cells from a biochemical perspective, seeking information on real-time dynamic processes, with an emphasis on the quantification of metabolic turnover. The aim is to provide a complementary method for metabolomics, and for toxicological and pharmacological studies, which does not require a priori selection of a target. The work highlights the methodological advances and proof-of-concept experiments that have taken place over the past few years in this direction. It discusses current advantages and limitations of the technique, including the possibility of detecting specific biomolecules and their reactivity, and it concludes with a brief outline of future perspectives.