posted on 2017-04-21, 00:00authored byEk Raj Thapaliya, Yang Zhang, Pravat Dhakal, Adrienne S. Brown, James N. Wilson, Kevin M. Collins, Françisco M. Raymo
Seven
macromolecular constructs incorporating multiple borondipyrromethene
(BODIPY) fluorophores along a common poly(methacrylate) backbone with
decyl and oligo(ethylene glycol) side chains were synthesized. The
hydrophilic oligo(ethylene glycol) components impose solubility in
aqueous environment on the overall assembly. The hydrophobic decyl
chains effectively insulate the fluorophores from each other to prevent
detrimental interchromophoric interactions and preserve their photophysical
properties. As a result, the brightness of these multicomponent assemblies
is approximately three times greater than that of a model BODIPY monomer.
Such a high brightness level is maintained even after injection of
the macromolecular probes in living nematodes, allowing their visualization
with a significant improvement in signal-to-noise ratio, relative
to the model monomer, and no cytotoxic or behavioral effects. The
covalent scaffold of these macromolecular constructs also permits
their subsequent conjugation to secondary antibodies. The covalent
attachment of polymer and biomolecule does not hinder the targeting
ability of the latter and the resulting bioconjugates can be exploited
to stain the tubulin structure of model cells to enable their visualization
with optimal signal-to-noise ratios. These results demonstrate that
this particular structural design for the incorporation of multiple
chromophores within the same covalent construct is a viable one to
preserve the photophysical properties of the emissive species and
enable the assembly of bioimaging probes with enhanced brightness.