Nov 15, 2012
Aptamer and peptide functionalized quantum dots recognize tumour cells
Aptamers and peptides have been quickly emerging as powerful classes of ligands for applications in optical molecular imaging thanks to their lack of immunogenicity, small size, ease of synthesis and similar targeting ability to antibodies. In a recent study, two different quantum dot fluorescent probes (QD-GS24 and QD-T7) – one based on aptamers and the other on peptides – were prepared and used for cell labelling.
Reporting their results in the journal Nanotechnology, researchers from Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology in China found that the aptamer- and peptide-functionalized probes were able to recognize B16 and Hela cells, respectively. In addition, the team observed that the labelling effects of these two probes could be promoted in the presence of the transferrin receptor native ligand-transferrin (Tf).
In the work, aptamer (GS24) and peptide (T7) molecules were covalently attached to the surface of the QDs using the cross-linker EDC and sulfo-SMCC, respectively. Spectra, DLS analysis and capillary electrophoresis (CE) revealed the conjugation of aptamer and peptide on QDs.
The researchers demonstrated the specificity of these two QD fluorescent probes (QD-GS24 and QD-T7) to B16 and HeLa cells using fluorescence microscopy and confocal microscopy. Quantitative flow cytometry analysis indicated that the transportation of QD-GS24 or QD-T7 into cells could be promoted by free transferrin.
The study has great significance for preparing QD fluorescent probes using non-antibody target molecules to image cancer cells.
A full description of the work can be found in the journal Nanotechnology.
About the author
Ming-Zhen Zhang is a PhD candidate in Prof. Yuan-Di Zhao’s group at Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, China. His research focuses on the biological modification of quantum dots and their application in imaging and gene therapy.