Jun 29, 2011
Labelling of human transferrin by fluorescent gold nanoclusters
Fluorescent labelling techniques have been used extensively in biological research, but are often limited by existing fluorophores, which suffer from inherent deficiencies such as photobleaching, toxicity or blinking. To overcome these issues, researchers from Saarland University (UdS) and the Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Germany, are looking at alternative biomarkers – in particular, the use of noble metal nanoclusters (NCs) for "tagging" human tranferrin, one of the most promising multitasking proteins for biomedical applications.
The team's approach exploits the remarkable properties of gold nanoclusters such as strong photostability and tunable size-dependent fluorescence properties. The labelled human transferrin exhibits good stability in solution and its protein functionality is conserved.
"If you want to use these modified proteins for biological applications, it's crucial to look at the cytotoxicity and the activity after labelling" explained Xavier Le Guevel, who took part in the work.
Data confirmed the ability of the fluorescent transferrin to i) uptake iron, one of its major functions in vivo, and ii) to recognize a specific polyclonal antibody. Furthermore, cell viability tests verified the non-toxic nature of the labelled proteins in A549 cells and cellular uptake of the iron-loaded fluorescent transferrin could be demonstrated.
These first results highlight the potential of a new type of fluorescent transferrin for biological application.
"The next step will be to investigate the specific cellular uptake of the labelled transferrin with and without iron" added Nicole Daum, another member of the HIPS-UdS team.
The findings were presented in the journal Nanotechnology.
About the author
The study was conducted by researchers from the Department of Pharmaceutical Nanotechnology at Saarland University (UdS) and the Helmholtz Institute for Pharmaceutical Research Saarland (HIPS). Dr Xavier Le Guevel is a postdoc at UdS awarded with a research fellowship from the Andalusian Initiative for Advanced Therapy. He is currently working on nanomaterials for protein labelling and drug-delivery systems. Dr Nicole Daum is senior scientist at the HIPS in Saarbrücken. She has a strong interest in the interaction of nanoparticles and biological systems, such as epithelial barriers. Dr Marc Schneider is professor for Pharmaceutical Technology and works on the interaction of nanoscale materials with biological matter. The use of these small particles for drug delivery is another facet of the group's research.