3D Hydrogen Titanate Nanotubes on Ti Foil: A Carrier for Enzymatic Glucose Biosensor

Abstract

Glucose oxidase (GOx) based biosensors are commercialized and marketed for the high selectivity of GOx. Incorporation nanomaterials with GOx can increase the sensitivity performance. In this work, an enzyme glucose biosensor based on nanotubes was fabricated. By using Ti foil as a carrier, hydrogen titanate nanotubes (HTNTs), which present fine 3D structure with vast pores, were fabricated in-situ by the hydrothermal treatment. The multilayer nanotubes are open-ended with a diameter of 10 nm. Then glucose oxidase (GOx) was loaded on the nanotubes by cross-linking to form an electrode of the amperometric glucose biosensor (GOx/HTNTs/Ti electrode). The fabricated GOx/HTNTs/Ti electrode had a linear response to 1–10 mM glucose, and the response time was 1.5 s. The sensitivity of the biosensor was 1.541 μA·mM-1·cm-2, and the detection limit (S/N = 3) was 59 μM. Obtained results indicate that the in-situ fabrication and unique 3D structure of GOx/HTNTs/Ti electrode are beneficial for its sensitivity.

Optimized Technologies for Cointegration of MOS Transistor and Glucose Oxidase Enzyme on a Si-Wafer

“…For better visibility, the CO 2 spectra bands in domain 2400–2200 cm −1 were removed ( Figure 8 ). In a previous publishing, the ATR-FTIR spectrum of untreated TiO 2 film revealed more diffuse and larger films [ 17 ]. Now, cleaner and steeper interfaces are produced.…”

“…The linear range can be approximated only for glucose concentrations sub-10 μM. The saturation regime seems to be the proper work regime for a good linearity in a larger glucose concentration range of −0.001 mM–100 mM—a larger range than the linear range of other glucose biosensors [ 16 ] but with a comparable detection limit to other biosensors [ 17 ]. Based on the excellent GOx selectivity, in conditions of nanostructured TiO 2 anchoring [ 29 ], we expect to avoid interferences with other -ose analytes, like lactose and fructose.…”

“…Another amperometric glucose biosensor, still transistorless, used a GOx receptor bound to hydrogen titanate nanotubes by crosslinking to form a working electrode. The fabricated GOx–Ti electrode had a linear response to 1–10 mM of glucose, a sensitivity of 1.541 μA·mM −1 per cm 2 , and a detection limit of 59 μM [ 17 ]. A technological solution to produce TiO 2 nanowires on a solid-state surface can be thermal oxidation for chemical gas sensing [ 18 ] or anodization for a glucose sensor [ 15 ].…”

“…By a separate experimental study, we investigated the nanostructured TiO 2 synthesis and the sensitive enzymatic membrane deposition on a Si-wafer. The following targets were exceeded versus the previous states [ 15 , 16 , 17 , 18 , 19 ]: (i) the fabrication steps of the ENFET include a channel conductivity correction, (ii) nanostructured Al 2 O 3 [ 20 ] or Si-porous [ 21 ] films are replaced by nanostructured TiO 2 films, (iii) nanostructured TiO 2 films and GOx membranes are characterized by SEM and FTIR, (iv) GOx membrane immobilization is optimized by alternative crosslink agents, and (v) a calibration curve is provided, and it is accompanied by an experimental model.…”

Constructive Optimization of a Multienzymatic Film Based on a Cascade Reaction for Electrochemical Biosensors

“… 23 , 24 According to this approach, the enzymes were randomly or regularly immobilized on a porous silicate support 25 coated with inorganic 13 or other support materials. 14 , 17 , 26 − 29 However, the diffusional distance and diffusive resistance affect each other because of the high-density immobilization in a solid of enzymatic materials. 30 Therefore, the immobilization strategy needs further studies, and the optimization is still under debate.…”