Defect-rich cypress-leaf-like Cu₂₊₁O@NiF for high-performance non-invasive glucose detection with low detection limit

Non-invasive detection of body fluid glucose concentration is of great significance in the diagnosis and treatment of diabetes, which poses a new challenge to the reduction of the detection limit of glucose sensors. In this work, a novel non-enzymatic glucose sensor (defect-rich cypress-leaf-like Cu₂₊₁O@NiF) was proposed by rapid electrodeposition of cypress-leaf-like Cu₂₊₁O on the surface of nickel foam (NiF) substrate. Due to the high electrochemical active surface area and abundant defects of cypress-leaf-like Cu₂₊₁O providing more catalytic active sites, the prepared non-enzymatic sensor has an ultra-low detection limit (0.9 nM), high sensitivity (88,419.4 μA∙mM⁻¹∙cm⁻² (1 nM-0.5 μM) and 2095.5 μA∙mM⁻¹∙cm⁻² (1 μM-4.33 mM)) and wide linear range (1 nM-4.33 mM) with good selectivity, reproducibility and stability. Furthermore, the obtained sensors exhibited high detection stability, accuracy and recovery for glucose detection of human body fluid samples, which means that the defect-rich cypress-leaf-like Cu₂₊₁O@NiF electrode is an ideal candidate for non-invasive glucose sensors.