Hyperbranched Polyglycerol Grafting on the Surface of Silica-Coated Nanoparticles for High Colloidal Stability and Low Nonspecific Interaction

Abstract

Silica coating is widely used for protecting nanoparticles from aggregation and in transforming them into functional nanoparticles of 10–100 nm size. However, synthesis of silica-coated nanoparticles of <50 nm size with low surface charge, high colloidal stability, and minimum nonspecific interaction with the bioenvironment is very challenging. Here, we report a generalized approach of hyperbranched polyglycerol grafting on the surface of silica-coated nanoparticles that significantly improves their colloidal stability and minimizes nonspecific interaction with biological interfaces. Method involves transformation of 5–10 nm hydrophobic nanoparticles into silica-coated and primary amine-terminated nanoparticles of <30 nm hydrodynamic size followed by ring opening polymerization of glycidol at the nanoparticle surface. Resultant hyperbranched polyglycerol grafted nanoparticles have <50 nm hydrodynamic size, ±5 to 10 mV zeta potential, high colloidal stability, and low nonspecific interaction with live cell...