Monolayer Protected Gold Nanoclusters

About

Introduction: Optical activities in the near-infrared (NIR) range are tremendously useful in biomedical applications like imaging and hyperthermia therapeutics. The global market for medical imaging was valued at $34.1 billion in 2018 and is expected to reach $43.6 billion by 2023. Extensive research efforts have been focused on the development of quality luminescent probes. However, for fluorescent probes to be effectively used in imaging applications, they need to exhibit high emission intensity with high quantum efficiency. Specifically, stability (both optical and chemical) needs to be improved for biological samples while maintaining reasonable aqueous solubility. Currently available near-IR dyes suffer from concerns of toxicity and other technical limitations such as photo blinking. Therefore, there is a need to develop new and improved imaging materials that provide better photostability, aqueous solubility, and quantum efficiency, particularly in the near-IR spectral range. Technology: Georgia State University researchers have invented monolayer protected clusters with improved photostability and quantum efficiency for medical imaging applications. Monolayer protected nanoclusters contain a cluster of atoms or molecules bound to a variety of ligands. In one example, these are gold nanoclusters (AuNCs), composed of a sub-2-nm Au core and surrounding organic molecules where the terminal groups of the organic molecules make the AuNCs water-soluble. They also comprise certain chemical structures as a unique parameter to enhance the quantum yield. With higher quantum yield, longer lifetime, less bleaching and quenching, improved chemical stability, and water solubility, these non-toxic AuNCs allow single cluster emissions to be measured.