Hyperbranched polyethylenimine–based polymeric nanoparticles: synthesis, properties, and an application in selective response to copper ion

Hyperbranched polyethylenimines (hPEIs) have diverse biological applications; however, the intrinsic toxicity is a major concern in developing hPEI-based biomaterials. This work reports the synthesis, properties, and an application as a biocompatible hPEI-based material, namely, fluorescent oxidized hPEI polymeric nanoparticles (F-ohPEIs). The synthesis was achieved through oxidation of hPEI with H2O2 and subsequent cross-linking with formaldehyde, imparting to F-ohPEIs’ desired properties such as remarkably reduced positive charge density, hydrolytic degradability, low cytotoxicity, strong fluorescence emission, and stability. Furthermore, as an application, F-ohPEI demonstrated the ability to selectively respond to cupric ion in a wide concentration range of 0.02 ~ 10 μM with a low limit of detection of 0.013 μM. The synthesis strategy along with the F-ohPEI nanoparticles developed in this work is expected to find promising application in fabricating biocompatible hPEI-based biomaterials.