Difluoroboron β-diketonate poly(lactic acid) (BF2bdkPLA) materials are useful imaging agents in biology and medicine. BF2bdk dyes are bright, photostable and color tunable across the visible range via ligand structure or dye loading. Furthermore, dye PLA materials are dual emissive, enabling ratiometric oxygen sensing, wherein the fluorescence signal serves as the standard and oxygen sensitive phosphorescence, as the sensor. Strategies for optimizing photostability and fluorescence and phosphorescence wavelengths, including singlet-triplet energy gaps and relative intensities, will be discussed. Portable, cost effective camera imaging is possible for dyes with good fluorescence and phosphorescence peak separation and alignment with camera RGB channels. Oxygen sensitivity is readily modulated via halide heavy atom substitution and polymer molecular weight to generate materials adapted for different biological contexts, with anoxic, hypoxic and full (0-100% O2) dynamic ranges. Dye-PLA conjugates are synthesized from dyeOCH2CH2OH initiators via ring opening polymerization of lactide or caprolactone monomers. Alternatively, dye-PLA-PEG analogues (PEG = poly(ethylene glycol)) are prepared by post polymerization modification. Phenolic dyeOH compounds are coupled with PLA-PEG via a Mitsunobu reaction. Dyes are fabricated as nanoparticles via nanoprecipitation for tissue application or IV delivery. Recent results in cells, tissues and in vivo will be presented, in tumor, wound, brain and immunological models.

Luminescent boron polymers for biomedical imaging

254th National Meeting (2017)

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