Biosearch Technologies’ Quasar 670 dye is listed as an alternative to the Cy 5 dye. Is it more resistant to photobleaching?

No, both Quasar™ 670 and Cy™ 5 share similar photobleaching characteristics. Like the original Cy5 dye, our Quasar 670 is not sulfonated and is based on the same indocarbocyanine as the Cy5 dye giving it nearly identical characteristics. We recommend commercial mounting media such as Vectashield® and imaging longer wavelength dyes first to help preserve the fluorescence signal. Visit our Stellaris Dyes and Modifications page for more information.