Figure 2

A high-resolution transmission electron microscopy image of HGNs. The particles are spherical and uniform in size. The gold layer is the dark gray area and the hollow inside of HGNs is clearly seen. HGN = hollow gold nanospheres.
A high-resolution transmission electron microscopy image of HGNs. The particles are spherical and uniform in size. The gold layer is the dark gray area and the hollow inside of HGNs is clearly seen. HGN = hollow gold nanospheres.