Jun 22nd

Today we measure the fuorescence lifetime of a fuorescent dye which is an organic molecule called ATTO 655. We use a setup consisting of 2 microscope, an atomic force microscope and a confocal fluorescence lifetime microscope. We prepare the molecules of ATTO 655 by taking 5 microliters of diluted dye and 3 microliters of pure water. We mixed the 2 drops of liquids and spreaded them on a coverslip in the laminar flowhood. We left the dye molecules to spread out into individual molecules on the coverslip for 10 minutes. Meanwhile we calibrated the 2 microscopes to send out pulses of red laser beams. The laser beam excites the ATTO molecules and the molecules fluoresce as a result of the excitation. We scan the coverslip to show the individual ATTO molecules. Next, we pick an ATTO molecule and beam a laser pulse onto the molecule. The molecule gets excited and fluoresce for a certain duration of time. The duration of time that the ATTO molecule fluoresce is called the fluorescence lifetime. We picked about 10 different ATTO molecules and measured their different fluorescence lifetimes.