Luminol/PtCo@rGO and Au@CNTs-based electrochemiluminescence cytosensor for ultrasensitive detection of breast cancer CTCs

Abstract

Background

Breast cancer CTCs have recently been recognized as an emerging biomarker for liquid biopsy of breast cancer. In this work, based on two-dimensional (2D) noble metal PtCo@rGO nanozymes and Au@CNTs bioconjugates, a novel electrochemiluminescence (ECL) cytosensor was was developed in order to detect breast cancer CTCs (MCF-7) ultrasensitively.

Results

The PtCo@rGO nanozymes possessed large specific surface area and high efficiency peroxidase-like activity, which can be used as nanocarriers to anchor and catalyze luminol ECL emission efficiently. Moreover, the PtCo@rGO nanozymes have fractal nanostructures similar to that of CTCs and can capable of enhancing the adhesion of MCF-7 when assembled together with aptamers containing HS-modified epithelial specific cell adhesion molecules (EpCAM, S1). Importantly, the S1/Au@CNTs bioconjugates loaded on the glassy carbon electrode (GCE) can effectively capture MCF-7 cells. Benefiting from the above-mentioned advantages, the ECL cytosensor constructed for MCF-7 cells detection performed well with a wide linear range (2 to 1×10⁴ cells mL^-1) and a low limit of detection (1 cells mL^-1).

Significance

The designed ECL cytosensor could provide a promising platform for CTC-based liquid biopsy and have broad application prospects in breast cancer early diagnosis and prognostic monitoring.