Raman microspectroscopy for non-invasive biochemical analysis of single cells

Recent developments in biomedical vibrational spectroscopy now permit the non-invasive imaging of cells and tissues within both the laboratory and clinical settings. The rapid nature and diagnostic potential of both Raman and FTIR (Fourier-transform IR) spectroscopy have resulted in their widespread application to a number of biological fields including fundamental cell biology, medical imaging, tissue engineering and pharmacology. In particular, Raman microspectroscopy shows tremendous promise for the analysis of biological processes within living cells, such as cell cycle dynamics, cell differentiation and cell death. Unlike conventional biological assays, laser-based Raman spectroscopy enables rapid and non-invasive biochemical analysis of cells in the absence of fixatives or labels. The low Raman signal of cell culture buffer/media permits the rapid monitoring of living cells growing under standard cell culture conditions. The Raman spectrum of a cell is a biochemical 'fingerprint', containing molecular-level information about all biopolymers contained within the cell. The high information content of Raman spectra can be used to characterize the distribution of multiple cellular components, and to study the dynamics of subcellular reactions, with excellent spatial resolution. This review highlights recent developments in Raman microspectroscopy, with a focus on non-invasive biochemical analysis of single living cells.