Semishell Janus Nanoparticle-Enabled pH-Responsive Rod-Shaped Assembly for Photothermal Therapy

The controllable aggregation of nanoparticles in solution is an important but unsolved problem in nanotechnology, which is mainly hindered by the symmetrical structure of the nanoparticles. Here, we propose an anisotropic semishell nanostructure to achieve the rod-shaped assembly of nanoparticles in solution. The isotropic Au@silica core–shell nanoparticles are self-assembled on the silicon wafer by the drop-casting technique to form a monolayer film. Au@silica semishell nanoparticles are obtained after selectively removing part of the silica shell by reactive ion etching. After functionalization with pH-sensitive 4-mercaptobenzoic acid molecules, the semishell nanoparticles display pH-responsive localized surface plasmon resonance coupling and near-infrared light absorption, thereby holding great potential for noninvasive photothermal therapy.