Hierarchical Mo2C@MoS2 Nanorods as Electrochemical Sensors for Highly Sensitive Detection of Hydrogen Peroxide and Cancer Cells

Abstract Heterostructures hierarchically integrating various building blocks are promising to construct sensitive and versatile biosensing platforms. Herein, hierarchical Mo2C@MoS2 consisting of interlayer-expanded MoS2 nanosheets wrapping on Mo2C nanorods is developed as a sensitive and bifunctional electrochemical platform to detect cellular metabolism products (e.g., H2O2) and cancer cells. Utilizing the merits of one-dimensional Mo2C axis (e.g., high conductivity) and two-dimensional MoS2 nanosheets (e.g., enhanced *OH binding, highly exposed edge-sites, and tolerance against oxidative H2O2), the Mo2C@MoS2 afford a high sensitivity (1080 μA mM-1 cm-2) and a low detection limit (0.2 μM) for H2O2 sensing, superior to the most of materials free from enzymes and noble metals. Its outstanding tolerance to various interferents ensures the practical monitoring of the intracellular H2O2 amount in MDA-MB-231, a human breast cancer cell line, which provides an indirect but available detection of tumor cells. As a versatile sensing platform, moreover the Mo2C@MoS2 with rich surface amino groups performs well to directly and specifically detect MDA-MB-231 after immobilizing folic acid. This work is anticipated to open up new opportunities toward high-performance sensing materials via surface/interfacial engineering on heterostructures.