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4-Amino-N-adamantylphthalimide (1) is a dye with moderate absorptivity (in CH3CN e363 = 4200 M−1 cm−1) and high quantum yield of fluorescence (ΦF = 0.15–0.80) that exhibits fluorosolvatochromic properties. The dye can be excited at 405 nm and the position of fluorescence maximum and the Stokes shift are well correlated with the ET(30) parameter. The excitation in the near-visible part of the spectrum and low cytotoxicity allow use of the dye in live cell microscopy. Due to its amphiphilic character, the dye stains artificial membranes in liposomes. Using confocal microscopy on two human cancer cell lines, we have shown that 1 stains primarily intracellular lipid droplets. Colocalization experiments with different organelle markers indicated that 1 additionally stains mitochondrial membranes. The fluorosolvatochromism of 1 allows the simultaneous visualization of mitochondria and intracellular lipid droplets in two separate emission channels, which has a potential use in cells and tissues exhibiting intense oxidative metabolism of lipids.

Publisher Summary This chapter describes reflection interference contrast microscopy (RICM). The term “RICM” is used in the chapter to cover all optical configurations and practical applications of the method. The method by which the light reflected from a semitransparent, epi-illuminated specimen contributes to the image formation in a microscope has been given different names, depending on details of the optical configuration of the microscope and on the particular application. It was introduced into cell biology by Curtis using the name “interference reflection microscopy” (IRM), and this name, or its variant, “reflection interference microscopy” (RIM), is often used in studies of adhesion of living cells. Ploem used the term “reflection contrast microscopy” (RCM) on the introduction of the antiflex method to increase image contrast. In RICM of living cells, reflections from the cell plasma membrane and intracellular membranes contribute to the image formation by interfering with each other and with the light reflected from the interface between the underlying glass surface and the liquid medium.