To date attempts to economically grow mushrooms have failed, leaving harvest from nature as the single source. We are pleased to tell you that you can now include Gold/Silica nanomushrooms on your menu, as András Deák and co-workers recently published their generation in Particle.
The scientists apply an interfacial preparation method: gold particles are partially embedded in a polystyrene layer that restricts silica shell growth from an aqueous solution to the exposed part, resulting in a cap-like structure. Thickness and coverage of the cap can be finely tuned through varying the polystyrene layer’s thickness and silica growth time. Finally the protective polystyrene layer is removed by plasma etching, yielding freestanding nanomushrooms on the substrate.
Apart from providing easy access to complex particle shapes, the method has a striking effect on the particles’ optical properties. Single-particle spectra show a red shift that reflects the extent of coverage of the gold core by the silica cap. This conclusion is supported by simulated single particle spectra and by near-field calculations. The system is suitable for plasmon coupling and resonance shift monitoring applications and will be interesting for theranostics, if coupled with biomolecules or fluorophores.