Seeded Growth of AuAg Solid–Hollow Janus Nanocrystals with Tunable Sizes for Photothermal Eradication of Multidrug-Resistant Bacteria

We report the preparation of plasmonic Janus nanostructures, composed of solid and hollow interiors, respectively, via a stepwise seeded growth. The success of the current synthesis highly relies on the construction of AuAg-based Janus nanocrystals with well-defined structures and the following controlled galvanic replacement reaction to prominently carve the Ag parts into hollow derivatives. With such unique architecture, they are enabled with the optical feature of dual plasmonic absorptions in the visible and near-infrared range and benefit the utilization of incident light and thus the photothermal conversion. The optimal temperature rise (ΔT) of the aqueous suspension was 15.2 °C after 10 min of 808 nm laser irradiation at a power density of 1.0 W cm–2, which was effective against multidrug-resistant bacteria in vitro. The current work shows a feasible synthetic strategy to create plasmonic Janus nanostructures featuring different porosities on each side, shedding light on rational design of advanced photothermal nanomaterials in biomedicine applications.