A new strategy for specific imaging of neural cells based on peptide-conjugated gold nanoclusters.

Despite the significant progress in molecular imaging technologies that has been made in recent years, the specific detection of neural cells still remains challenging. Here, we suggest the use of gold nanoclusters (AuNCs) modified with a brain-targeting peptide as a potential imaging candidate for detecting neural cells in vitro and in mice. AuNCs of less than 10 nm (dynamic light scattering analysis) were first prepared using the "green" synthetic approach, and then a targeting peptide, rabies virus glycoprotein derived peptide (RDP), was conjugated to the AuNCs for improving the efficiency and specificity of neural cell penetration. The conjugate's mechanism of cellular attachment and entry into neural cells was suggested to be receptor-mediated endocytosis through clathrin-coated pits. Also, noninvasive imaging analysis and animal studies indicated that the RDP-modified nanoclusters could concentrate in the brain and locate in neural cells. This study suggests the feasibility of using targeting peptide-modified nanoclusters for noninvasive imaging brain cells in vivo.