Label-free detection of folate receptor (+) cells by molecular recognition mediated electrochemiluminescence of CdTe nanoparticles.

Molecular recognition based rapid and simple techniques for identifying subtypes of cancer cells are essential in molecular medicine. In this work, we have designed a molecular recognition mediated electrochemiluminescent (ECL) strategy for label-free and sensitive detection of folate receptor (FR) (+) cells (HeLa cell as a model) on folic acid-functionalized and red emitting CdTe/GSH nanoparticle-modified indium-tin oxide (ITO) electrodes. The ECL emission selectively responses to the rapid binding of FR (+) cells on the modified ITO electrodes due to the block of electron exchange between CdTe nanoparticles and coreacted dissolved oxygen. Microscopic observation verifies that the binding of HeLa cells is more favored than that for HepG2 cells [FR (-) type], resulting in a great difference in ECL intensity. The proposed platform allows the detection of ~35 cells from 10 μL of cell suspension. This study has laid the foundation for building rapid and low-cost ECL diagnostic devices for specific detection of FR (+) cancer cells, with potential applications in profiling of cancer cell subtypes.