Biosensing the Presence of Nanoparticles Using Endogenous Fluorescence in Live Algae

Nanoparticles (NPs) from various metals (Zinc, Nickel, Cobalt, Copper) were designed and fabricated by direct synthesis using femtosecond laser ablation in liquids. Employing confocal microscopy with spectral detection and fluorescence lifetime imaging (FLIM), we have evaluated interaction of fabricated NPs with living Chlorella sp. algae by means of their naturally presented endogenous fluorescence. Live cell imaging was done in spectral region 500-550 nm and 650-710 nm to evaluate the effect of NPs on both, the green and the red fluorescence that is derived from flavonoids/carotenoids and chlorophylls respectively. We observed fluorescence intensity decrease in the red spectral region by all but Ni NPs. The presence of NPs also lead to an increase in the blue fluorescence at 477-488 nm, possibly resulting from reflected light. Gathered observations constitute the first step towards creation of methodological approaches for fast natural biosensing of the effects of environmental pollution directly in live algae.