SPY620-actin is a bright red & non toxic live and fixed cells F-actin stain based on SPYâ„¢ dyes series. Its optimized structure allows quick labeling of F-actin in live & fixed cells with high specificity and very low background. SPY620-actin is identical to MAP618-actin described in the nature chemistry article by the lab of Kai Johnsson. SPY620-actin stains F-actin of live or fixed cells without the need for genetic manipulation or overexpression of fluorescent proteins. Its emission in the red minimizes phototoxicity and sample autofluorescence. SPY620-actin enables multicolor imaging with SPY505, SPY555, SPY650, SPY700, SiR & GFP. SPY620-actin can be imaged with e.g. using 610/20 nm and 650/40 nm excitation and emission filters respectively. It can be used for widefield, confocal, SIM or STED imaging in living or fixed cells and tissue.Â