Transmission infrared micro-spectroscopic study of lactic acid production in cultured cells

Early detection of cancer, preferably in a non-invasive manner, is of utmost importance in combating the disease. Since transmission infrared (IR) spectroscopy allows the identification and estimation of chemical compounds in living cells, we designed a chamber with a 12-μm optical path to obtain microscopic transmission IR spectra of two cell lines, NIH/3T3 and MCA205. We report a characteristic absorption peak in cancerous MCA205 cells that may be attributed to the production of lactic acid. Differences in the amount of lactic acid were also detected in non-cancerous NIH/3T3 cells, according to their density. These observations suggested IR spectroscopy as a useful non-invasive technique to screen cells with specific metabolic signatures.