We report on efforts to improve the lifetime of biological lasers through the use of ascorbic acid (also commonly known as vitamin C). Fluorescent proteins and dyes, used in biological lasers, suffer from photobleaching due to the build-up of reactive oxygen species (ROS) which causes damage leading to a decrease in emission over time. This is an issue both for laser lifetime and cell health. It has previously been shown that ascorbic acid can be effective in reducing ROS levels in a variety of applications. For our experiments human embryonic kidney cells (HEK293), containing the fluorescent dye Calcein AM, were placed between two dielectric plane mirrors to form a laser cavity. The cells were pumped using the output of a Ti:Sapphire femtosecond OPO system, frequency doubled twice in BBO crystals, giving an output of 474 nm. Initial results have shown an increase in laser lifetime when ascorbic acid is added to cells indicating a reduction in the build-up of ROS.
Ajoy K. Kar, Mark D. Mackenzie, Katarzyna I. Cialowicz, Rebecca S. Saleeb, and Rory R. Duncan, "Vitamin C for stabilising biological lasers
(Conference Presentation)," Proc. SPIE 9711, Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues IX, 97111K (Presented at SPIE BiOS: February 17, 2016; Published: 27 April 2016); https://doi.org/10.1117/12.2211720.4848767221001.
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