Non-Enzymatic Glucose and Cholesterol Biosensors Based on Silica Coated Nano Iron Oxide Dispersed Multiwalled Carbon Nanotubes

We report for the first time a non-enzymatic glucose biosensor fabricated using monodispersed SiO₂ coated magnetic Fe₃O₄ dispersed multiwalled carbon nanotubes (Fe₃O₄@SiO₂/MWNT) which has been successfully tested for rapid detection of glucose without the interference due to uric and ascorbic acids. This super paramagnetic nanocomposite, Fe₃O₄@SiO₂/MWNT combines the excellent electron transfer properties of nano Fe₃O₄, biocompatibility of nano sized silica and electron transport properties of MWNT. The electrochemical performance of the non-enzymatic biosensor has been investigated by cyclic voltammetry and amperometric i-t studies. The linearity of fabricated electrode for glucose detection is 3 μM to 14 mM. The same material is used for non-enzymatic cholesterol biosensor also. It shows a detection range of 10 μM to 4mM towards cholesterol. Moreover, the electrodes show good detection limit, high sensitivity and good selectivity in both the cases. A thin coating of Nafion is used to avoid the interference due to uric acid (UA) and ascorbic acid (AA).