Poly(amino acid)-based nanogel by horseradish peroxidase catalyzed crosslinking in an inverse miniemulsion.

We present an investigation of horseradish peroxidase (HRP)/H2O2-mediated crosslinking in an inverse miniemulsion for the successful preparation of a stable colloidal nanogel from a poly(amino acid)-based polymer precursor. The precursor was obtained by the aminolysis of polysuccinimide with aminoethan-2-ol and tyramine, resulting in a poly(α,β-<italic>N</italic>-(2-hydroxyethyl)-D,L-aspartamide-<italic>co</italic>-<italic>N-</italic>(2-(4-hydroxyphenyl)ethyl)-D,L-aspartamide) polymer (PHEA-Tyr). Various concentrations of the PHEA-Tyr in aqueous solution with HRP were emulsified in the presence of cyclohexane and SPAN 80. The addition of a hydrogen peroxide solution induced crosslinking between the polymer chains via the phenol groups (Tyr) and targeted nanogel formation. The hydrodynamic radii (<italic>R</italic><italic>h</italic>0), mean size documented by hydrodynamic radius (<italic>R</italic><italic>h</italic>), and morphology of the nanoparticles were investigated by dynamic light scattering (DLS) measurements, nanoparticle tracking analysis (NTA), and cryogenic transmission electron microscopy (cryo-TEM). It was found out that nanoparticle radius, morphology, and architecture of the nanogel could be regulated by the initial concentration of the precursor. [ABSTRACT FROM AUTHOR]