Free-standing MXene/chitosan/Cu2O electrode: an enzyme-free and efficient biosensor for simultaneous determination of glucose and cholesterol

In summary, a free-standing MXene/CTS/Cu2O electrode was formed through electrostatic interaction of MXene and CTS with opposite charges, followed by the electrodeposition of Cu2O. Taking advantage of the synergistic function of MXene/CTS layers and Cu2O nanoparticles, this ternary electrode exhibits excellent sensing capabilities for glucose and cholesterol with preferable linear ranges that can cover the full concentration range in clinical diagnosis. For glucose sensing, the sensitivity was 60.295 µA·L/(mmol·cm2) with LOD being 52.4 µmol/L (SNR=3), while a sensitivity up to 215.71 µA·L/(mmol·cm2) and LOD low to 49.8 µmol/L (SNR=3) were achieved for cholesterol detection. Additionally, this biosensor possesses superior anti-interference ability and reproductivity, and thus exhibits great potential for genuine sample analysis. Accordingly, the as-prepared enzyme-free MXene/CTS/Cu2O electrode acts as a biomimetic electrocatalyst with excellent performance for analysis of multiple metabolites, and overcomes the disadvantages of an enzyme-based biosensor. This work has proposed a versatile strategy for designing and fabricating selfassembled nanocomposite materials with tuned structural and functional properties. It is a first attempt which could be easily integrated into portable electrochemical devices, facilitating effective routine monitoring of blood metabolites and paving the way for commercialization and point-of-care testing.