ZnO Nanoparticle Modification by Polyethylenimine for Biomolecule Conjugation

Abstract

This study aims to find a way for the creation of polyethyleneimine-modified biofunctionalized zinc oxide (ZnO) nanoparticles, stable in phosphate buffered saline (PBS). Biofunctionalized ZnO nanoparticles are promising for bioanalitycal applications due to a combination of diverse physico-chemical ZnO properties and selectivity of biomolecules. ZnO nanoparticles were synthesized in diethylene glycol media at 150°C. Different strategies were utilized for ZnO nanoparticle modification in order to disclose the role of polyethylenimine (PEI) in stability of colloidal system. Synthesized and modified ZnO nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and infrared spectroscopy measurements, and stability of colloidal system was investigated using DLS data. Finally, ability of ZnO nanoparticles to attach proteins for potential analytical applications was proved using Bradford protein assay. Among different strategies of modification, ZnO nanoparticles modified by trisodium citrate, PEI and glutaraldehyde (GA) have showed the best stability in PBS while preserving low aggregation level and high positive surface charge.