To study the mechanisms of and conditions for adipogenesis, an accurate in situ observation tool is necessary to monitor the quantity of intracellular neutral lipids in differentiating preadipocytes. Although conventional fluorescence intensity imaging is a powerful tool for observing the formation and growth of an individual lipid droplet, it suffers from photobleaching and ambiguous autofluorescence or background signals from cells. In this paper, we present a fluorescence lifetime imaging microscopy (FLIM) technique that has the potential to quantify the ratio of neutral to polar lipids in a cell. Measurement of time-lapse FLIM images of differentiating 3T3-L1 cells that contained the Nile Red (NR) probe showed that the average lifetime of NR decreased from 4 ns in preadipocytes to 3 ns in fully differentiated adipocytes after 10 days of differentiation. This large change in the lifetime of NR can be used to monitor the early stages of adipogenesis, even when the lipid droplet is too small to be identified with a conventional microscope.
Bibliographical noteFunding Information:
This work was financially supported by the MEST through the National Research Foundation of Korea (grant No. 2012R1A4A1029061 ), which is supported financially by the Institute of Physics and Applied Physics at Yonsei University through the BK21 program.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physics and Astronomy(all)