The hydrophilic structures of hydrogels hold large amounts of water in their three-dimensional networks, rendering them high physiochemical similarity to the extracellular matrices.3 Besides, enclosure of nanomaterials can improve the structural diversity and functionality of hydrogels, making it stimuli responsive.4 Typically, responses to external stimuli, including metal ions, pH, temperature, light, added nucleic acid fuel, redox potential, etc., can be introduced via modification of the polymer structures of hydrogels. Such stimuli-responsive hydrogels have great application potentials in controlled drug release, catalysis, programmed cell growth, and sensing. Few redox-responsive hydrogels have been reported by far, with more responding to reducing conditions via introduction of thiol groups to the polymer structures, than to oxidation conditions, sensing of which is through enzyme encapsulation. Herein, we report the ROS-responsive micron-sized hydrogel particles, i.e.  microgel, by enclosing the ZnS-containing NPs in the gel network. Adding a low content of Cu2+ to the enclosed NPs can produce a peroxidase mimicking microgel that can produce large amounts of hydroxyl radicals from ROS like H2O2. The reaction releases Zn2+ to turn on the zinc-responsive dye. In this way, the microgel can turn the potentially-instable presence of ROS into the stable and bright fluorescent signals, so that they can act as the sensor for ROS as well as for the ROS-producing small molecules of biomedical interest, such as glucose and cholesterol. Such microgels can also act as labeling reagents and be applied to detect other biomarkers such as extracellular vesicles with high sensitivity.<br/> <br/>

Peroxidase-mimicking microgels fabricated by encapsulation of ionic nanoparticles and their applications in biomarker detection

256th National Meeting (2018)

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