Enhanced electrochemiluminescence cytosensing based on abundant oxygen vacancies contained 2D nanosheets emitter coupled with DNA device cycle-amplification.

Developing efficient and sensitive cytosensing method has great significance for the detection of low abundant circulating tumor cells (CTCs). Electrochemiluminescence (ECL) biosensor, as an attractive analytical tool, has shown a great potential in sensitive cell counting. Its detection efficiency is strongly dependent on the electrochemiluminescent materials, whose property is related to its morphology and surface vacancies. Herein, the ultrathin Lu2O3-S nanosheets contain abundant oxygen vacancies were newly synthesized. Its special two-dimensional (2D) structure morphology and surface vacancy endowed it intensified and stable ECL emission. The possible mechanism was deduced from experiments and discussed. Then, through integrating with a DNA device cycle-amplification system plus signal conversion pretreatment, we constructed a crossed enhanced ECL cytosensing platform. In this system, the target cells were transformed into programmable sequences, which could be next coupled with DNA device cycle-amplification on the modified electrode surface. Using Ag2S quantum dots as the energy acceptor toward Lu2O3-S donor, and CCRF-CEM cells (CEM) as the model CTCs, an enhanced ECL cytosensing platform was proposed, displaying good analytical performance for acute lymphoblastic leukemia cancer cell detection. The ECL signal responded proportionately on the CEM cells concentration in a wide range of 5 × 10 to 1 × 106 cells/mL, and a low detection limit of 10 cells/mL was obtained. This work provided an alternative way to design high-performance ECL luminophores, and also would be an effective solution for CTCs counting.