Simultaneous detection of MCF-7 and HepG2 cells in blood by ICP-MS with gold nanoparticles and quantum dots as elemental tags.

In this work, we demonstrate a novel method based on inductively coupled plasma mass spectrometry (ICP-MS) detection with gold nanoparticles (Au NPs) and quantum dots (QDs) labeling for the simultaneous counting of two circulating tumor cell lines (MCF-7 and HepG2 cells) in human blood. MCF-7 and HepG2 cells were captured by magnetic beads coupled with anti-EpCAM and then specifically labeled by CdSe QDs-anti-ASGPR and Au NPs-anti-MUC1, respectively, which were used as signal probes for ICP-MS measurement. Under the optimal experimental conditions, the limits of detection of 50 MCF-7, 89 HepG2 cells and the linear ranges of 200-40000 MCF-7, 300-30000 HepG2 cells were obtained, and the relative standard deviations for seven replicate detections of 800 MCF-7 and HepG2 cells were 4.6% and 5.7%, respectively. This method has the advantages of high sensitivity, low sample consumption, wide linear range and can be extended to the simultaneous detection of multiple CTC lines in human peripheral blood.

A fluorescence turn-on biosensor based on graphene quantum dots (GQDs) and molybdenum disulfide (MoS2) nanosheets for epithelial cell adhesion molecule (EpCAM) detection.

This paper presents a "turn-on" fluorescence biosensor based on graphene quantum dots (GQDs) and molybdenum disulfide (MoS2) nanosheets for rapid and sensitive detection of epithelial cell adhesion molecule (EpCAM). PEGylated GQDs were used as donor molecules, which could not only largely increase emission intensity but also prevent non-specific adsorption of PEGylated GQD on MoS2 surface. The sensing platform was realized by adsorption of PEGylated GQD labelled EpCAM aptamer onto MoS2 surface via van der Waals force. The fluorescence signal of GQD was then quenched by MoS2 nanosheets via fluorescence resonance energy transfer (FRET) mechanism. In the presence of EpCAM protein, the stronger specific affinity interaction between aptamer and EpCAM protein could detach GQD labelled EpCAM aptamer from MoS2 nanosheets, leading to the restoration of fluorescence intensity. By monitoring the change of fluorescence signal, the target EpCAM protein could be detected sensitively and selectively with a linear detection range from 3nM to 54nM and limit of detection (LOD) around 450pM. In addition, this nanobiosensor has been successfully used for EpCAM-expressed breast cancer MCF-7 cell detection.

Epithelial cell adhesion molecule independent capture of non-small lung carcinoma cells with peptide modified microfluidic chip.

Circulating tumor cells (CTCs) present in the blood of patients with non-hematological cancers are accessible sources for diagnosis and monitoring of cancers. By the aid of the ability of the anti-EpCAM antibody to recognize the epithelial cells, microsystem-based technologies provide robust means for effectively detecting CTCs in vitro. Considering the EpCAM expression is down-regulated during epithelial-mesenchymal transition (EMT) process, the amount of CTCs detected based on anti-EpCAM antibody is underestimated. In our study, the A549 cells targeting peptide (A-1 peptide), as the substitute of anti-EpCAM antibody, was introduced to microfluidic chip to capture A549 cells. Our results showed that both epithelial-like and mesenchymal-like A549 cells could efficiently be captured by the A-1 peptide modified microfluidic chip, and the capture efficiency for epithelial-like cells is comparable to that captured by the EpCAM antibody. Thus, we concluded that the peptide could be a better supplement to the EpCAM antibody for capturing CTCs in microfluidic system with broader spectrum.