Cyclic RGD peptide conjugated trypsin etched gold quantum clusters: novel biolabeling agents for stem cell imaging.

Quantum clusters are sub-nano sized materials mostly synthesized from noble metals with luminescence property and high quantum yield. They are important to biomedical scientists because of their excellent optical properties. Here we represent a tool for cell imaging purpose using protein stabilized gold quantum clusters. Intestinal protease Trypsin was used to develop clusters. They were conjugated to cyclic RGD peptides by EDAC coupling. Cell imaging property was checked by transfecting the RGD-conjugated quantum clusters to bone marrow stem cells. For characterization of RGD-conjugated quantum clusters UV-Vis, Fluorescence and FTIR spectroscopy was performed. DLS and Zeta potential measurement also have been done. To check the bio compatibility of the quantum clusters MTT assay, AFM and blood cell adhesion study were performed. The samples are found out to be good for cell imaging as well as bio compatible and hemo-compatible.