Hydrogen peroxide is an important product of oxygen metabolism: it is necessary to cellular fitness, but when misregulated, it can cause oxidative stress inside cells. Developing a polymeric system that can serve as an imaging probe for the detection of excess H2O2 in living systems is, therefore, of interest. To address this problem, we developed a boronate-based bis-norbornene derivative that enables the brush-first synthesis of uniform brush-arm star polymers (BASPs). Degradation of boronate-core cross-linked particles into bottlebrush polymers in the presence of H2O2 was assessed by gel permeation chromatography (GPC) as well as dynamic light scattering (DLS). We combined this new cross-linker with a spirocyclohexyl nitroxide (chex)-branched macromonomer (chex-MM), a reduction resistant cyclohexyl nitroxide MM that displays high relaxivity and stability, for the synthesis of chex-BASPs. Exposure to H2O2 and the subsequent chex-BASP degradation into bottlebrushes can be detected by magnetic resonance imaging (MRI) as the relaxation properties of these nitroxide radical-based nanostructures changes. This new cross-linker is an important addition to our brush-first ROMP system for BASP as an imaging platform. Such a system can potentially allow real-time detection of oxidative stress inside of cells as well as precisely deliver drugs to cells with increased levels of H2O2.

Synthesis of hydrogen peroxide sensitive chex-conjugate nanoparticles via brush-first ROMP

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.