Compact fluorescence system with fiber-coupled LED for studying photobleaching

Laser-induced fluorescence systems that are used in fluorescence research are expensive. This study demonstrated a novel, cheap, and compact fluorescence system comprising a fiber-coupled LED and pinholes to achieve a confocal arrangement. For investigating photobleaching, two model fluorescence dyes-fluorescein and calcein-were successfully tested using this platform. The results indicated that the two dyes exhibit similar self-quenching phenomena. Photobleaching by using the two dyes under normalized intensity was evaluated using a double-negative exponential model. The photobleaching rate increased with the dye concentration.