Highly specific electrochemical analysis of cancer cells using multi-nanoparticle labeling.

Circulating tumor cells (CTCs) can be collected noninvasively and provide a wealth of information about tumor phenotype. For this reason, their specific and sensitive detection is of intense interest. Herein, we report a new, chip-based strategy for the automated analysis of cancer cells. The nanoparticle-based, multi-marker approach exploits the direct electrochemical oxidation of metal nanoparticles (MNPs) to report on the presence of specific surface markers. The electrochemical assay allows simultaneous detection of multiple different biomarkers on the surfaces of cancer cells, enabling discrimination between cancer cells and normal blood cells. Through multiplexing, it further enables differentiation among distinct cancer cell types. We showcase the technology by demonstrating the detection of cancer cells spiked into blood samples.