Glucose sensing performance of bimetallic MOFs CoFe-ZIF/CC for enzyme-free saliva sensor applications

Co-ZIF is widely believed as a promising material which shows potential in MOFs based enzyme-free sensors. However, the research of Co-ZIF in glucose sensor filed has been hampered, due to its poor electronic conductivity and slow ion diffusion caused by closed rhombohedral dodecahedron structure. In this work, the obtained Co0.95Fe0.05-ZIF presents highly opened nanosheet structure on CC, resulting in rich open active sites and ions moving channels. Compared with other reported ZIFs, the Co0.95Fe0.05-ZIF/CC exhibits excellent sensing performance with a high sensitivity of 3232.30 μA mM−1 cm−2 in the range of 0.20–1.00 mM and a low detection limit of less than 5 μM, due to its highly opened nanosheet structure. The Co0.95Fe0.05-ZIF/CC also shows excellent selectivity, repeatability and reproducibility for glucose detection. Furthermore, the variation trend of test results measured by this saliva sensor without any sample pre-treatment, is consistent with that of commercial blood glucose meter, indicating its potential in real applications. This synthesis strategy also provides a new direction of structure construction for high performance MOFs in enzyme-free glucose sensor field.