Luminescent quantum clusters of gold in bulk by albumin-induced core etching of nanoparticles: metal ion sensing, metal-enhanced luminescence, and biolabeling

Chemistry. 2010 Sep 3;16(33):10103-12. doi: 10.1002/chem.201000841.


The synthesis of a luminescent quantum cluster (QC) of gold with a quantum yield of approximately 4 % is reported. It was synthesized in gram quantities by the core etching of mercaptosuccinic acid protected gold nanoparticles by bovine serum albumin (BSA), abbreviated as Au(QC)@BSA. The cluster was characterized and a core of Au(38) was assigned tentatively from mass spectrometric analysis. Luminescence of the QC is exploited as a "turn-off" sensor for Cu(2+) ions and a "turn-on" sensor for glutathione detection. Metal-enhanced luminescence (MEL) of this QC in the presence of silver nanoparticles is demonstrated and a ninefold maximum enhancement is seen. This is the first report of the observation of MEL from QCs. Folic acid conjugated Au(QC)@BSA was found to be internalized to a significant extent by oral carcinoma KB cells through folic acid mediated endocytosis. The inherent luminescence of the internalized Au(QC)@BSA was used in cell imaging.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cations / chemistry
  • Cattle
  • Gold / chemistry*
  • Humans
  • Luminescence
  • Metal Nanoparticles / chemistry*
  • Serum Albumin, Bovine / chemistry*


  • Cations
  • Serum Albumin, Bovine
  • Gold