Fluorescent labeled polymers are extensively used to monitor internalization and intracellular trafficking of polymers and polymer nanoparticles. There are, however, also some drawbacks and limitations related to the use of fluorescent dyes. Exposure of polymer-dye conjugates to the degradative intracellular environment, for example, can result in release of the dye. Furthermore, there is the risk for pH- and concentration-dependent quenching or photobleaching. Last but not least, fluorescent labels may alter the uptake or intracellular trafficking behavior of the polymer. Over the past years, an increasing number of techniques has become available that do not require the use of fluorescently-labeled polymers. This includes Raman spectroscopy as well as nanoscale secondary ion mass spectrometry (NanoSIMS) and synchrotron X-ray fluorescence imaging. As a consequence, there is a need for simple and efficient protocols to synthetize polymers that are labeled with isotopes and trace elements. This presentation will report the preparation of fluorine-chain-end-labeled side chain reactive polymers via RAFT polymerization of pentafluorophenyl methacrylate (PFMA) mediated by two new fluorinated chain transfer agents (CTAs), which contained either one (R) or two (R,Z) fluorine labels. While the α-label, which derives from the R-group, is introduced for bioimaging purposes, the ω-label that is due to the Z-group allows to monitor end-group fidelity of the PPFMA polymers produced via this process using <sup>19</sup>F-NMR spectroscopy. The PPFMA polymers are attractive since they serve as a platform for post-polymerization modification and can be converted to generate α-fluorine, ω-Rhodamine red end-labeled poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA), which serves as a proof-of-concept since this polymer has been widely used for the preparation of polymer-drug conjugates. Uptake and intracellular trafficking of this PHPMA polymer was studies with confocal microscopy and NanoSIMS.

Trace element and isotope labels to study uptake and intracellular trafficking of polymer conjugates

256th National Meeting (2018)

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