<title>Study the autofluorescence of microalgae inducted by laser using laser scanning confocal microscope</title>

Abstract

In this present paper, the microalgae irradiated by Nd:YAP laser are observed using Laser Confocal Scan microscope, and the auto fluorescence of microalgae cells is analyzed with quantitative analysis system, so as to investigate the effect of auto fluorescence alteration on growth of irradiated microalgae. Method: Platymonas subcordiformis, Phaeodactylum tricormutum and Isochyrsis zhanjiangensis are irradiated by Nd:YAP laser with 10w at 1341nm, irradiating time:12s, 30s, 35s and 55s. On Lambda Scan mode, the auto fluorescence images and fluorescence spectra of algae cells are obtained by the excitation 488nm (Ar⁺ laser). Result: there are two summit peaks, 489.8nm and 680.9nm, for Platymonas subcordiformis, Phaeodactylum tricormutum and Isochyrsis zhanjiangensis fluorescence spectrum. Contrast to the CK, the peak positions of fluorescence of irradiated algae cells is similar to the whole while the peak light intensity alters. On irradiation of promoting dose, however, the auto fluorescence intensity is enhanced more than control, with different type of microalgae, the different fluorescence intensity are shown in the analysis, and all of the microalgae pigment bodies change can be seen also. Conclusion: Physiological incentive effect of irradiated microalgae can be given expression on fluorescence characteristics and fluorescence intensity alteration of cells.