A novel cytosensor based on Pt@Ag nanoflowers and AuNPs/Acetylene black for ultrasensitive and highly specific detection of Circulating Tumor Cells.

Circulating tumor cells (CTCs), as the cellular origin of metastasis, are cancer cells that break away from a primary tumor and circulate in the peripheral blood. And they provide a wealth of information about tumor phenotype. Here, this work reported a novel ultrasensitive immunoassay protocol for the detection of CTCs by using Pt@Ag nanoflowers (Pt@AgNFs) and AuNPs/Acetylene black (AuNPs/AB) nanomaterial. In the established approach, AuNPs/AB nanomaterial was used as substrate material to increase the specific surface area and enhance the conductivity of the gold electrode. Protein G was used for oriented immobilization of capture antibody, which strongly improved the capture efficiency of MCF-7 cells. The innovatively synthesized Pt@AgNFs by our group with high specific surface area and good biocompatibility were not only as the carriers of signal antibodies (Ab2) but also catalyzed the reduction of H2O2, which effectually amplified the current signal. A linear relationship between current signals and the concentrations of CTCs was obtained in the range from 20 to 1×106 cells mL-1 and the detection limit is as low as 3 cells mL-1 on condition of acceptable stability and reproducibility. Furthermore, the as-proposed cytosensor showed excellent performance in the detection of CTCs in human blood samples. These results suggest that the proposed cytosensor will be a promising application for accurately quantitative detection of CTCs.