FRAP/ Conference poster (Client: University of Oxford) / FRAP is a non-invasive technique for investigating molecular dynamics within living cells. It has been successfully used to study gap junction-mediated communication in different cell types, including cells derived from horse tendons. The cells are labelled with a permeable fluorescent dye, such as calcein acetoxymethylester (AM) a nonfluorescent dye, which is converted by intracellular esterases to green-fluorescent and membrane-impermeable calcein. Next, a cell of interest is selected, bleached using an argon-ion laser (488nm) and subsequently a time-lapse series is taken to record calcein recovery.