title: Rapid Cationization of Gold Nanoparticles by Two-Step Phase Transfer.
abstract: Cationic gold nanoparticles offer intriguing opportunities as drug carriers and building blocks for self-assembled systems. Despite major progress on gold nanoparticle research in general, the synthesis of cationic gold particles larger than 5 nm remains a major challenge, although these species would give a significantly larger plasmonic response compared to smaller cationic gold nanoparticles. Herein we present the first reported synthesis of cationic gold nanoparticles with tunable sizes between 8-20 nm, prepared by a rapid two-step phase-transfer protocol starting from simple citrate-capped particles. These cationic particles form ordered self-assembled structures with negatively charged biological components through electrostatic interactions.
authors.affiliation: Department of Applied Physics, Aalto University, Puumiehenkuja 2, 02150 Espoo (Finland).
authors.forename: Jukka
authors.initials: J
authors.lastname: Hassinen
authors.affiliation: Department of Biotechnology and Chemical Technology, Aalto University, Kemistintie 1, 02150 Espoo (Finland).
authors.forename: Ville
authors.initials: V
authors.lastname: Liljeström
authors.affiliation: Department of Biotechnology and Chemical Technology, Aalto University, Kemistintie 1, 02150 Espoo (Finland).
authors.forename: Mauri A
authors.initials: MA
authors.lastname: Kostiainen
authors.affiliation: Department of Applied Physics, Aalto University, Puumiehenkuja 2, 02150 Espoo (Finland). robin.ras@aalto.fi.
authors.forename: Robin H A
authors.initials: RH
authors.lastname: Ras
keywords: gold; nanoparticles; phase transfer; self-assembly; surface plasmon resonance