Difluoroboron β-diketonate (BF2bdks) materials find application in oxygen sensing and imaging. In suitable matrices such as poly(lactic acid) (PLA), BF2bdks produce both oxygen-insensitive fluorescence (F, internal standard), and oxygen-sensitive phosphorescence (P, sensor) for ratiometric imaging (F/P). With discrete F and P emission peaks, a simple red/green/blue (RGB) camera can be used to measure the oxygen levels. In this work, a new series of iodo BF2bdk dyes were optimized for F and P peak separation, relative intensity and alignment with RGB channels. The iodide heavy atom increases the rate of intersystem crossing (ISC) and activates strong phosphorescence. Dyes were also modified with a -OC12H25 alkoxy chain to improve solubility and minimize aggregation both during dye synthesis and fabrication of dye/PLA blends. Optical properties of dyes were studied in CH2Cl2 solution, PLA films, and PLA-PEG nanoparticles and promising oxygen-sensing materials were produced. For example, the meta-alkoxy-substituted dibenzoylmethane dye has fluorescence that corresponds to the blue channel and strong phosphorescence that spans across the green emission region. Also, a dithienylmethane dye exhibits blue fluorescence and red phosphorescence (595 nm), useful for imaging in biological environments. Among the candidates, these two dyes enable oxygen imaging in blue/green and blue/red camera channels. These findings set the stage for the preparation of dye-polymer conjugates and bioimaging with a RGB camera.

Difluoroboron β-diketonates for ratiometric oxygen imaging with a color camera

254th National Meeting (2017)

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