Local environment of the lipid droplets inside the breast cancer cells, MCF7 and in non-malignant breast cells, MCF10A is monitored using time-resolved confocal microscopy. For this study, a coumarin-based dye C153 has been used. The local polarity and the solvation dynamics indicate that a cytoplasmic lipid droplet is less polar and displays slower solvation dynamics compared to the cytosol. Significant differences in terms of number of lipid droplets, polarity and solvation dynamics are observed between the cancer cell (MCF7) and its non-malignant cell (MCF10A). (C) 2016 Elsevier B.V. All rights reserved.