Application For Glucose Biosensing Research Articles

Enhanced solid-state electrochemiluminescence of Ru(bpy)32+ immobilized on a laponite gel-state network and its glucose biosensing application

A novel laponite network thin film (denoted as laponitegel-film) was prepared by casting a laponite suspension with salt onto the surface of a glassy carbon electrode (GCE) to incorporate Ru(bpy)32+. The resultant Ru(bpy)32+-laponitegel-film/GCE presented significantly enhanced electrochemiluminescence (ECL) behavior. Thus, a glucose ECL biosensor was developed with a good performance.

Glucose oxidase and graphene bionanocomposite bridged by ionic liquid unit for glucose biosensing application

Ionic liquid functionalized graphene (IL-graphene) composite was synthesized successfully through an epoxide ring-opening reaction between graphene oxide (GO) and amine-terminated ionic liquid (NH 2-IL). The IL-graphene exhibited good electronic conductivity, stability and electrocatalytical activity towards the reduction of O 2 and H 2O 2. Then negatively charged glucose oxidase (GOD) was immobilized onto the composite matrix simply by ionic exchange. The ionic liquid here could improve the dispersibility of graphene and provide a favorable conductive microenvironment for the immobilized GOD, thus promote its direct electron transfer at the GC electrode. This novel IL-graphene–GOD bionanocomposite could act as a biosensor towards the detection of glucose with a linear response up to 16 mM. In this report, the method for immobilizing GOD by ionic interaction is of universality and has widespread use, even in other biological systems, which brings a forceful combination between GOD and IL-graphene. Besides, the biosensor is easy to prepare, have good stability, and will have potential application in glucose detection.

One-step “green” preparation of graphene nanosheets and carbon nanospheres mixture by electrolyzing graphite rob and its application for glucose biosensing

The graphene nanosheets and carbon nanospheres mixture (GNS–CNS) was prepared by electrolyzing graphite rob in KNO 3 solution under constant current, which was characterized by TEM, AFM, SEM, FT-IR, XRD, XPS, TGA and UV–vis. The nano-mixture can keep stable in water for more than one month. Based on this kind of mixture material, a novel electrochemical biosensing platform for glucose determination was developed. Cyclic voltammetry of glucose oxidase (GOD) immobilized on GNS–CNS/GCE exhibited a pair of well-defined quasi-reversible redox peaks at −0.488 V ( E pa) and −0.509 V ( E pc) by direct electron transfer between the protein and the electrode. The charge-transfer coefficient ( α) was 0.51, the electron transfer rate constant was 2.64 s −1 and the surface coverage of HRP was 3.18 × 10 −10 mol cm −2. The immobilized GOD could retain its bioactivity and catalyze the reduction of dissolved oxygen. The glucose biosensor has a linear range from 0.4 to 20 mM with detection limit of 0.1 mM. Moreover, the biosensor exhibits acceptable reproducibility and storage stability. The fabricated biosensor was further used to determine glucose in human plasma sample with the recoveries from 96.83% to 105.52%. Therefore, GOD/GNS–CNS/GCE could be promisingly applied to determine blood sugar concentration in the practical clinical analysis.

Synthesis and application of poly-SNS-anchored carboxylic acid: a novel functional matrix for biomolecule conjugation

Here we report the synthesis of a novel conducting polymer and its properties as an immobilization platform for biosensor application. The conducting polymer has functional groups used for the formation of amide bonding with the enzyme immobilized on the polymer surface. After covalent immobilization of glucose oxidase (GOx) on the polymeric matrix, its application for glucose biosensing was investigated in detail. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and contact angle measurements were used to monitor the surface properties of the polymer before and after biomolecule conjugation. The optimized biosensor showed a very good linearity between 0.01 mM and 1.2 mM, a 13 s response time and a detection limit (LOD) of 0.004 mM to glucose. Also, kinetic parameters, operational and storage stabilities were determined. Apparent Michaelis constant (Kmapp) and Imax values of 1.17 mM and 11.28 μA, respectively, were obtained.

Development of high-kTm2Ti2O7 sensing membrane-based electrolyte–insulator–semiconductor for pH detection and its application for glucose biosensing using poly(N-isopropylacrylamide) as an enzyme encapsulation material

In this study, we report an electrolyte–insulator–semiconductor (EIS) device with a novel high-k Tm2Ti2O7 sensing membrane for pH detection. In this research, the sensing membrane was fabricated by reactive sputtering and postdeposition annealing treatment. The effect of thermal annealing (700, 800, and 900 °C) on the structural and surface properties of the Tm2Ti2O7 sensing membrane was investigated by X-ray diffraction, secondary ion mass spectrometry, X-ray photoelectron spectroscopy, and atomic force microscopy. The observed properties were then correlated with the resulting EIS pH sensing performances. The results disclosed that the pH sensing based on the EIS structure with the sensing membrane annealed at the higher temperature of 900 °C showed a higher detection sensitivity (59.38 mV pH−1), smaller hysteresis voltage (2.4 mV), and lower signal drifting rate (0.568 mV h−1), compared with those annealed at a lower annealing. These results are attributed to the formation of a crystalline oxide thin film with a rougher surface in this condition. Moreover, for EIS-based biosensing applications, a phase tunable poly-N-isopropylacrylamide (PNIPAAm) was used as an enzyme encapsulating material in this study, making the loading and removal of a biological recognition element on a biosensor easy. In this work, a hybrid configuration of the proposed Tm2Ti2O7 membrane-EIS with glucose oxidase-immobilizing PNIPAAm film attached was established and was demonstrated for glucose biosensing. Results demonstrated that the proposed biosensor was able to detect glucose with good linearity (R2 = 0.99) and reasonable sensitivity of 14.66 mV mM−1 in the glucose concentration range of 2–8 mM. Overall, the presented work has provided some fundamental data on the use of Tm2Ti2O7 sensing membrane for EIS-based pH detection, and has also demonstrated the feasibility of using the PNIPAAm to encapsulate enzyme molecules for the biosensing applications.

A comprehensive review of glucose biosensors based on nanostructured metal-oxides.

Nanotechnology has opened new and exhilarating opportunities for exploring glucose biosensing applications of the newly prepared nanostructured materials. Nanostructured metal-oxides have been extensively explored to develop biosensors with high sensitivity, fast response times, and stability for the determination of glucose by electrochemical oxidation. This article concentrates mainly on the development of different nanostructured metal-oxide [such as ZnO, Cu(I)/(II) oxides, MnO2, TiO2, CeO2, SiO2, ZrO2, and other metal-oxides] based glucose biosensors. Additionally, we devote our attention to the operating principles (i.e., potentiometric, amperometric, impedimetric and conductometric) of these nanostructured metal-oxide based glucose sensors. Finally, this review concludes with a personal prospective and some challenges of these nanoscaled sensors.

Direct electrochemistry of glucose oxidase on the hydroxyapatite/Nafion composite film modified electrode and its application for glucose biosensing

A novel glucose biosensor was constructed by immobilizing the glucose oxidase (GOD) on a hydroxyapatite (HAp)/Nafion composite film modified glassy carbon electrode (GCE) and applied to the highly selective and sensitive determination of glucose. With the cooperation of HAp and Nafion, the composite film played an important role in enhancing the stability and sensitivity of the biosensor. The results demonstrate that the GOD adsorbed onto the HAp/Nafion composite film exhibits a pair of well-defined nearly reversible redox peaks and fine catalysis to the oxidation of glucose companied with the consumption of dissolved oxygen. On the basis of the decrease of the reduction current of dissolved oxygen at the applied potential of −0.80 V (vs. SCE) upon the addition of glucose, the concentration of glucose could be detected sensitively and selectively. The decreased reduction current was linear with the concentration of glucose in the range of 0.12–2.16 mM. The detection limit and sensitivity were 0.02 mM (S/N = 3) and 6.75 mA·M−1, respectively. All the results demonstrate that HAp/Nafion composite film provides a novel and efficient platform for the immobilization of enzymes and realizes the direct electrochemistry. The composite materials should have potential applications in the fabrication of third-generation biosensors.

Preparation of gold nanoparticles/functionalized multiwalled carbon nanotube nanocomposites and its glucose biosensing application

Gold nanoparticles stabilized by amino-terminated ionic liquid (Au-IL) have been in situ noncovalently deposited on poly(sodium 4-styrene-sulfonate) (PSS)-functionalized multiwalled carbon nanotubes (MWCNTs) to form a MWCNTs/PSS/Au-IL nanocomposite. PSS can interact with MWCNTs through hydrophobic interaction. Amino-terminated ionic liquid was applied to reduce aqueous HAuCl 4, and the resulting gold nanoparticles were attached to the PSS-functionalized MWCNTs simultaneously. Most gold nanoparticles dispersed well on the functionalized MWCNTs. Transmission electron microscopy, Raman and X-ray photoelectron spectroscopy were used to confirm the composition and structure of the nanocomposites. The resulting MWCNTs/PSS/Au-IL composite exhibits good electrocatalysis toward oxygen and hydrogen peroxide reduction. And good biocompatibility with glucose oxidase was also demonstrated due to its good biocatalysis toward glucose substrate, which offered a friendly environment for the immobilization of biomolecules. Such bionanocomposite provides us potential applications in fabrication of biosensors. The resulting biosensor exhibits good response to glucose with a low detection limit 25 μM. It also has excellent reproducibility, satisfied operational stability and good storage stability.