Article pubs.acs.org/cm
Control of Ultrasmall Sub-10 nm Ligand-Functionalized Fluorescent Core−Shell Silica Nanoparticle Growth in Water Kai Ma,† Carlie Mendoza,† Margaret Hanson,‡ Ulrike Werner-Zwanziger,‡ Josef Zwanziger,‡ and Ulrich Wiesner*,† †
Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14850, United States Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
‡
S Supporting Information *
ABSTRACT: Ultrasmall fluorescent silica nanoparticles (SNPs) and core−shell SNPs surface functionalized with polyethylene glycol (PEG), specific surface ligands, and overall SNP size in the regime below 10 nm are of rapidly increasing interest for clinical applications, because of their favorable biodistribution and safety profiles. Here, we present an aqueous synthesis methodology for the preparation of narrowly size-dispersed SNPs and core−shell SNPs with size control below 1 nm, i.e., at the level of a single atomic layer. Different types of fluorophores, including near-infrared (NIR) emitters, can be covalently encapsulated. Brightness can be enhanced via addition of extra silica shells. This methodology further enables synthesis of
