High Sensitive Glucose Sensor Research Articles

High-sensitive glucose sensor based on tilted fiber Bragg gratings

In this paper, we proposed a high-sensitive glucose sensor using the tilted fiber Bragg gratings (TFBGs). The TFBGs with different tilt angle has been fabricated by phase mask scanning method with an argon ion double-frequency 244 nm laser. As tilt angle increases, the bandwidth of the cladding mode excited by TFBGs gradually expands and cladding mode region shifts towards shorter wavelengths. The higher-order cladding modes appeared at the shorter wavelength side demonstrate a larger separation in the spectrum. TFBGs with different tilt angles for glucose concentration measurement have been investigated experimentally. When the concentration of glucose solution increases, the surrounding refractive index changing make the cut-off mode resonance shift to a longer wavelength. In addition, the tilt angle of TFBGs does affect the glucose sensitivity, that the larger tilt angle is, the higher sensitivity could achieve. In this work, a maximum glucose sensitivity of 80.91 pm/(mg/ml) could be obtained for TFBGs with tilt angle of 10°. The proposed TFBGs with superiorities of high glucose sensitivity and wider detection range, makes it potential for glucose detection in the field of chemical and biomedical sensing.

Facile preparation of a CoNiS/CF electrode by SILAR for a high sensitivity non-enzymatic glucose sensor.

The nanomaterials for non-enzymatic electrochemical sensors are usually pre-synthesized and coated onto electrodes by ex situ methods. In this work, amorphous cobalt-nickel sulfide (CoNiS) nanoparticles were facilely prepared on copper foam (CF) by the in situ successive ionic layer adsorption and reaction (SILAR) method, and as-prepared CoNiS/CF was studied as an electrode for non-enzymatic glucose sensing. It was analyzed by field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDAX) and X-ray photoelectron spectroscopy (XPS). The electrochemical performance was investigated by cyclic voltammetry (CV) and chronoamperometry (CA). This binary sulfide electrode showed better performance toward glucose oxidation compared to the corresponding single sulfide and showed a wide linear range of 0.005 to 3.47 mM, a high sensitivity of 2298.7 μA mM-1 cm-2 and a low detection limit of 2.0 μM. The sensor exhibited high sensitivity and good repeatability and stability and was able to detect glucose in an actual sample. This work provides a simple and fast in situ electrode preparation method for a high-sensitivity glucose sensor.

A high sensitive glucose sensor based on Ag nanodendrites/Cu mesh substrate via surface-enhanced Raman spectroscopy and electrochemical analysis

A high sensitive micro/nano-structured glucose sensor via Surface Enhanced Raman Spectroscopy (SERS) detection and electrochemical analysis was developed in this work. Ag nanodendrites/Cu mesh substrate were prepared through facile electrochemical deposition method, which exhibited high SERS sensitivity and electrocatalytic activity. By SERS measurements, glucose can be detected as low as 0.005 mM and exhibit a good linear relationship between concentrations (0.5–5 mM) and the SERS intensities. Moreover, glucose in human urine with different concentrations were successfully detected by the substates. By electrochemical method, the conductivity was firstly tested by CV and ESI tests. Amperometric responses of 0.5 mM glucose were compared with Cu mesh electrode, and the Ag nanodendrites/Cu mesh electrode showed higher electrochemical detection sensitivity. Results revealed the Ag nanodendrites/Cu mesh substrate can be used as glucose sensor with high detection sensitivity, reproducibility, selectivity and practicability, which has great potential in noninvasive medical diagnosis in further works.

High sensitivity detection of glucose with negatively charged gold nanoparticles functionalized the gate of AlGaN/GaN High Electron Mobility Transistor

A high sensitivity glucose sensor using AlGaN/GaN based high electron mobility transistor (HEMT) was fabricated. The 3-aminopropyltriethoxysilane (APTES) was aligned to the GaN surface by forming the covalent linkage between them. The negatively charged gold nanoparticles (AuNPs) can be effectively self-assembled on the positively charged APTES surface. The morphology of the immobilized AuNPs was observed by the field emission scanning electron microscope (FE-SEM). The chemical groups after APTES/AuNPs functionalization were confirmed by X-ray photoelectron spectroscopy (XPS). Glucose oxidase (GOx) was immobilized on the APTES/AuNPs functionalized the gate surface through electrostatic attraction. From the analysis of the current signals, our glucose sensor exhibited wide detection range from 0.001 to 9 mM with higher sensitivity of above 1 × 106 μA mM-1 cm-2. It showed a quick response time of less than 8 s and a detection limit of 1 nM. Furthermore, it was found that the performance of detection after AuNPs attachment can be increased by 15 % as compared to the HEMT sensor without AuNPs. The apparent Michaelis-Menten constant KMαpp was calculated about 0.06 mM, indicating high affinity of GOx to glucose. Consequently, proposed strategy for the AuNPs-gated AlGaN/GaN HEMT could be an efficient immobilization platform for biosensing of the different bio-analytes.

Osmotic induction of calcium accumulation in human embryonic kidney cells detected with a high sensitivity FRET calcium sensor

Calcium serves as a second messenger in glucose-triggered insulin secretion of pancreatic cells. Less is known about sugar signaling in non-excitable cells. Here, the high sensitivity FRET calcium sensor TN-XXL was used to characterize glucose-induced calcium responses in non-excitable human embryonic kidney HEK293T cells. HEK293T cells responded to perfusion with glucose with a sustained and concentration-dependent increase in cytosolic calcium levels. Sucrose and mannitol triggered comparable calcium responses, suggesting that the increase of the calcium concentration was caused by osmotic effects. HEK293T cells are characterized by low endogenous glucose uptake capacity as shown with a high sensitivity glucose sensor. Consistently, when glucose influx was artificially increased by co-expression of GLUT glucose transporters, the glucose-induced calcium increase was significantly reduced. Neither calcium depletion, nor gadolinium or thapsigargin were able to inhibit the calcium accumulation. Taken together, membrane impermeable osmolytes such as sucrose and mannitol lead to an increase in calcium levels, while the effect of glucose depends on the cell's glucose uptake capacity and will thus vary between cell types in the body that differ in their glucose uptake capacity.