Gold nanoparticles with special shapes: Controlled synthesis, surface-enhanced Raman scattering, and the application in biodetection

Specially shaped gold nanoparticles have intrigued considerable attention because they usually possess high-sensitivity surface-enhanced Raman scattering (SERS) and thus result in large advantages in trace biodetermination. In this article, starch-capped gold nanoparticles with hexagon and boot shapes were prepared through using a nontoxic and biologically benign aqueous-phase synthetic route. Shape effects of gold nanoparticles on SERS properties were mainly investigated, and found that different-shaped gold nanoparticles possess different SERS properties. Especially, the boot-shaped nanoparticles could induce more 100-fold SERS enhancements in sensitivity as compared with those from gold nanospheres. The extremely strong SERS properties of gold nanoboots have been successfully applied to the detection of avidin. The unique nanoboots with high-sensitivity SERS properties are also expected to find use in many other fields such as biolabel, bioassay, biodiagnosis, and even clinical diagnosis and therapy.