Iron oxide nanozyme as catalyst of nanogelation

•Iron oxide nanoparticles were successfully prepared.•Iron oxide nanozyme catalyzed formation of covalently crosslinked nanogel.•Hydrogel nanoparticles with diameter below 100 nm were successfully prepared. Iron oxide nanoparticles (IONPs) with intrinsic peroxidase-like activity were proven to be effective and direct catalyst of the nanogelation of synthetic polypeptide precursor poly[N5-(2-hydroxypropyl)-L-glutamine-ran-N5-propragyl-L-glutamine-ran-N5-(6-aminohexyl)-L-glutamine]-ran-N5-[2-(4-hydroxyphenyl)ethyl)-L-glutamine] (P2HPG). IONPs catalytic activity and kinetics were determined to mimic the horseradish peroxidase (HRP) used in the nanogelation of the polymer precursor containing a phenol moiety. The prepared nanogels were characterized by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), and (cryogenic) transmission electron microscopy (cryo-TEM/TEM). Smart IONPs-catalyzed nanogelation resulted in soft and spherical nanoparticles with diameter of approximately 80 nm.