Lipid Science & Technology

Although numerous investigators have studied lipid droplets formation through several imaging techniques, they can’t draw conclusions regarding the overall process of lipid metabolism in live cells. Here, a method for studying lipid metabolism with high spatial and temporal resolution is presented, based on the measurement of intracellular polarity through the solvatochromic and lipophilic probe Nile red, which undergoes to a red shift upon a change of polarity of the neighboring lipids. A confocal spectral imaging approach captures in detail polarity variations by acquiring the fluorescence emission spectra at pixel resolution. The analysis of the spectra trough the technique of spectral phasors allowed semi-blind spectral unmixing of the contribution of different classes of lipids in the image, namely hyper polar, polar and non-polar lipids. The method allows a fine-tuned, real-time monitoring of fatty acid metabolism in live cells with submicrometric resolution.

Figure 1: Overview of fatty acid metabolism, and relative change of polarity of the Nile Red probe.