Cytodiagnostics Gold NanoUrchins have unique optical properties compared to spherical gold nanoparticles of the same core diameter. The spiky uneven surface causes a red shift in the surface plasmon peak and a larger enhancement of the electromagnetic field at the tips of the Gold NanoUrchin spikes compared to that of a spherical particles. As an example, 100nm spherical gold nanoparticles have an SPR peak at 570nm while 100nm Gold NanoUrchins have a SPR peak at around 680nm, figure 1.
Figure 1. Left) UV-VIS spectra of 100nm Gold NanoUrchins (blue) and 100nm standard gold nanoparticles (green). Note the red-shift in the SPR-peak. Right) UV-VIS spectra of Gold NanoUrchins ranging in size from 50nm to 100nm in diameter.
Binding of ligands such as proteins to the Gold NanoUrchin surface also causes a larger shift in the surface plasmon resonance peak compared to standard spherical gold nanoparticles. This feature makes them ideal in the development of sensitive SPR-based detection assays, figure 2.
Our Gold NanoUrchins are available in 6 different sizes with a multitude of surface chemistries, see product categories below.
Figure 2. Refractive index induced shift of the lambda max (LSPR-shift) for standard gold nanoparticles and gold nanourchins upon addition of glycerol.