Studies on microplastics cyanobacteria and algae using a 67-channel spectral flow cytometer and widefield fluorescence research microscope.
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Detection of microplastics in cells
Fluorescent microplastics particles were accumulated into cells using an in vitro cellular model system. These submicron fluorescence particles between 20 and 500 nm were detected in cells by measuring their fluorescence intensity of the cells using a flow cytometer. It was found that the cells incorporated 200nm particles in a dose dependent manner. The results were confirmed by fluorescence microscopy showing the particles within the cells. A technique called widefield confocal microscopy was made to ensure that the particles were located within the cells. The particles appeared to be concentrated primarily in the endoplasmic reticulum surrounding the nuclei. There was a mitochondrial concentration located in the vicinity of the particles. This uptake of particles may result in a cellular toxic response which will be investigated in the future using flow cytometry and microscopic fluorescence assays.
Characterization of Cyanobacteria and Algae by Flow Cytometry spectral differences
Algae and cyanobacteria each have a preferential absorption of specific wavelengths of light dependent on the photosynthetic pigments contained within the organism. The absorption of light by green algae is primally accomplished by chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoids using the primarily blue and red spectral regions to absorb light. Cyanobacteria contain phycobilin pigments (phycoerythrin and phycocyanin) that preferentially absorb green and orange spectral light. The excitation of phycocyanin/phycoerythrin cyanobacteria and green algae with different wavelengths of laser light results in fluorescent emissions that are spectrally different from each other. This difference can be detected better using new Cytek Aurora Flow cytometer that has 5 lasers and 67 detectors. The absorption differences between the two species cannot only be used for flow cytometry applications but, these differences can be used to better image algae and cyanobacteria by fluorescence microscopy. This abstract does not reflect USEPA policy.