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

• Published in: ACS sustainable chemistry & engineering Vol. 5; no. 6; pp. 4879 - 4889
• Main Authors: Panja, Prasanta, Das, Pradip, Mandal, Kuheli, Jana, Nikhil R
• Format: Journal Article
• Language: English
• Published: American Chemical Society 05.06.2017
• Subjects: Silica coating; Hyperbranched polyglycerol; Colloidal stability; Nanoparticle; Polyethylene glycol
• ISSN: 2168-0485; 2168-0485
• DOI: 10.1021/acssuschemeng.7b00292

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 cells. The developed grafting approach has been successfully applied to four different nanoparticles such as CdSe-ZnS-based red fluorescent quantum dots, Mn-ZnSeS-based orange fluorescent-doped nanocrystals, γ-Fe2O3-based magnetic nanoparticles, and Au-based plasmonic nanoparticles. As silica coating is well established for a wide variety of nanoparticles, the presented approach can be extended to these nanoparticles for enhancing their application potential.