Iodide-Mediated Rapid and Sensitive Surface Etching of Gold Nanostars for Biosensing

Iodide-mediated surface etching can tailor the surface plasmon resonance of gold nanostars through etching of the high-energy facets of the nanoparticle protrusions in a rapid and sensitive way. By exploring the underlying mechanisms of this etching and the key parameters influencing it (such as iodide, oxygen, pH, and temperature), we show its potential in a sensitive biosensing system. Horseradish peroxidase-catalyzed oxidation of iodide enables control of the etching of gold nanostars to spherical gold nanoparticles, where the resulting spectral shift in the surface plasmon resonance yields a distinct color change of the solution. We further develop this enzyme-modulated surface etching of gold nanostars into a versatile platform for plasmonic immunoassays, where a high sensitivity is possible by signal amplification via magnetic beads and click chemistry.

Automated summary

Iodide-mediated surface etching allows for tailoring the surface plasmon resonance of gold nanostars rapidly and sensitively. This technique shows potential in sensitive biosensing systems by exploring key parameters like iodide, oxygen, pH, and temperature. The enzyme-modulated surface etching of gold nanostars can be developed into a versatile platform for plasmonic immunoassays, offering high sensitivity through signal amplification with magnetic beads and click chemistry.