Microwave-Assisted Formation of Gold Nanoclusters Capped in Bovine Serum Albumin and Exhibiting Red or Blue Emission

• Published in: Journal of physical chemistry. C 2017-12, Vol.121 (48), p.26997-27003
• Main Authors: Chuang, Kuan-Ting, Lin, Yang-Wei
• Format: Article
• Language: English
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.7b09349

In this study, a microwave-assisted method for preparing fluorescent gold nanoclusters capped in bovine serum albumin (AuNCs@BSA) was developed. Through fluorescence spectrometry, transmission electron microscopy, and X-ray photoelectron spectroscopy (XPS), the effect of reaction temperature on the size and oxidation state of AuNCs@BSA samples was determined. Blue-emitting AuNCs@BSA (B-AuNCs@BSA), with weak bonds between AuNCs and BSA, were prepared at 135 °C. Red-emitting AuNCs@BSA (R-AuNCs@BSA) were also formed, and their formation was followed by an aggregation of polydispersed AuNCs@BSA. Through infrared spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, it was confirmed that the R-AuNCs@BSA, consisting of 18 Au atoms, was successfully embedded in BSA. In addition, XPS measurements revealed that Au+ ions were present only in the R-AuNCs@BSA. Steady-state and lifetime results revealed the importance of the size and oxidation state of Au+ in the stabilization of the AuNCs@BSA and in the presence of a long lifetime component.