Optimization of Thiolate Stabilized Gold Nanoclusters For Near Infrared Emission in Subcellular Imaging

• Main Author: Conroy, Cecil Vincent
• Format: Others
• Published: ScholarWorks @ Georgia State University 2014
• Subjects: Gold nanoclusters; Thiol; Near-IR luminescence; Confocal imaging
• Online Access: http://scholarworks.gsu.edu/chemistry_theses/64; http://scholarworks.gsu.edu/cgi/viewcontent.cgi?article=1063&context=chemistry_theses

Monothiolate protected gold nanoclusters with near IR luminescence underwent a five-to-ten fold enhancement of quantum efficiency by heating in the presence of excess thiols. Two monothiolate nanoclusters, mercaptosuccinic acid and tiopronin, were shown to benefit from this procedure. Emission maximum around 700-900 nm is favorable for bioimaging applications due to reduction of background signal from autofluorescence. Dithiolate lipoic acid protected gold nanoclusters with higher near IR quantum efficiency present an interesting candidate for biological imaging due to the difference in hydrophobicity, resistance to quenching by divalent cations and cell growth media, and retained quantum efficiency when coupled to agents such as polyethylene glycol. Intracellular and nuclear internalization of mercaptosuccinic gold nanoclusters demonstrate a potential vector for delivery of nuclear targeting agents. The small size, chemical stability, high luminescence, and potential for targeting various intracellular domains make gold nanoclusters worthwhile for further studies as potential bioimaging probes.