Fabrication Of Nanostructures On Iron Foil And Stainless Steel Foil For High-performance Nonenzymatic Glucose Sensors

There are approximately100million people suffered from diabetes mellitus inChina. Frequent monitoring of the blood glucose level is critical to patients to avoiddiabetic emergency. Electrochemical glucose sensors based on glucose oxidase (GOx)have attracted considerable attention and have become a dominant figure in biosensormarket due to their good sensitivity, selectivity, simplicity, and compatibility inreal-time detection. However, the enzyme-based sensors are sensitive to light,temperature and pH value and usually suffer from limited lifetime and consumption ofthe valuable enzyme reagent. Enzyme-free glucose sensors fabricated by metal ormetal oxide such as Pt, Pd, Ag, Cu and Ni, have been intensively studied recently.Ferrite has been extensively employed in biological devices for their chemicalstability, biocompatibility and non-toxic to humans. But there are few reports todevelop glucose sensors based on iron oxides. Moreover, the overall kinetics ofglucose oxidation on ferrite is too slow to produce adequate faradaic currents, thusleading to poor sensitivity. Herein, nanostructured glucose sensors fabricated on ironfoil and stainless steel foil were described. The nanorod array and nanopore arraystructures not only possess high surface-to-volume ratio, but also provide a directelectron transfer pathway that can enhance the analytical performance of glucosesensors. The morphology, microstructure, and chemical composition of thesenanostructures were characterized by SEM, EDS, XRD and Raman spectrum. Theanalytical performance of the glucose sensors was evaluated by cyclic voltammetryand amperomertic i-t curve.(1) An enzyme-free electrochemical sensor for glucose was prepared byelectrochemical anodization of iron foil, followed by in situ annealing under aflow of hydrogen to give a one-dimensional Fe3O4nanorod array (NRA). Themorphology, structure, and composition of the NRAs were characterized andthe fabrication process was investigated. The array possesses a large specificsurface area and a crystal structure that facilitates electron transfer. Operated at 0.6V (vs. SCE) in pH13solution, the sensor displays a distinctly improvedsensitivity to glucose (compared to their Fe2O3nanotube counterpart). Twolinear response ranges can be observed. The first extends from0.5μM to766μM (with a sensitivity of406.9μA cm-2mM-1, the other from765μM to3.7mM (with a sensitivity of134.1μA cm-2mM-1). The detection limit is0.1μM(S/N=3). The reproducibility of1D Fe3O4NRAs electrode is evaluated byamperometric detection with10successive injections of glucose. The relativestandard deviation (RSD) of4.8%indicates the excellent reproducibility. Thesensor also shows good stability after storage over45days. Moreover, the1DFe3O4NRAs electrode suffers minimal interferences from the easily oxidativespecies in blood serum such as dopamine, ascorbic acid, uric acid4-acetaminophenol, serotonin, mannose and fructose. The good agreementbetween the results obtained by conventional methods in a local hospital andthis glucose sensor indicates that the1D Fe3O4NRAs is a promising candidatein clinical applications.(2) A high-performance enzyme-free sensor for glucose was prepared byelectrochemical anodization of316L stainless steel, followed with chemicaldeposition in0.1M NaOH solution. The as-prepared three dimensional@nanopores (aciculas@NPs) displayed enhanced analyticalperformance toward glucose determination, with a detection limit of0.5μMand a sensitivity of202.2μA cm2mM1from1μM to1.2mM. Thereproducibility of the aciculas@NPs electrode is evaluated by. The RSD of4.9%obtained from amperometric detection with10successive injections ofglucose indicates the excellent reproducibility. The sensor also shows goodstability after storage over45days. Moreover, the aciculas@NPs electrodesuffers minimal interferences from the easily oxidative species in blood serumsuch as ascorbic acid and uric acid. There is a good agreement between theresults obtained by conventional methods in a local hospital and this glucosesensor. The aciculas@NPs electrode exhibits good stability, favorable reproducibility and potential applications for real sample analysis thusrendering it suitable for clinical applications.