An innovative glucose biosensor using antibiofouling Au-F127 nanospheres.

Quantification of the blood glucose concentration in the whole blood was not easy to achieve because the detection process was affected by many factors, such as glucose metabolism and biofouling. In this paper, we established an amperometric glucose biosensor applied in whole blood directly, which was based on the direct electron transfer of glucose oxidase (GOx) entrapped onto the Au-F127 nanospheres. Here, the Au-F127 nanospheres could provide a blood compatible surface with antifouling property for determination of glucose in whole blood. The cyclic voltammetric results indicated that GOx immobilized on the Au-F127 nanospheres exhibited direct electron transfer reaction, and the cyclic voltammogram (CV) displayed a pair of well-defined and nearly symmetric redox peaks with a formal potential of 93 mV. The biosensor had good electrocatalytic activity toward glucose with a low detection limit 3.15 pM. The glucose biosensor did not respond to ascorbic acid (AA) and uric acid (UA) at their high concentration encountered in blood. In this method, the biosensor was used for quantification of the concentration of glucose in whole blood samples. The data obtained from the biosensor showed good agreement with those from a biochemical analyzer in hospital.

Innovative biocompatible nanospheres as biomimetic platform for electrochemical glucose biosensor.

In this work, the silica- phytic acid (SiO2-PA) nanocomposites were synthesized by the method of reverse microemulsion and electrostatic binding. The newly designed materials were used to develop a novel glucose biosensor by immobilizing glucose oxidase (GOx) onto the SiO2-PA nanocomposites film on the surface of glassy carbon electrode (GCE). The characteristics of SiO2-PA nanocomposites and GOx were obtained by using transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and circular dichroism (CD) technique. All the results indicated that silica nanoparticales were modified with phosphate radicals successfully and the biomimetic surface was built. The entrapped GOx could preserve its bioactivity and exhibited an excellent electrochemical behavior with a formal potential of -0.548 V in phosphate buffer solution (PBS) (pH=7). Response studies to glucose were carried out using differential pulse voltammetry (DPV). The results indicated that the modified electrode can be used to determine glucose without interference from l-ascorbic acid (AA) and uric acid (UA) with the low detection limit of 0.012 mM. The comparison tests of DPVs of different electrodes in the absence and presence of glucose were also studied. The biosensor can also be used for quantification of the concentration of glucose in real samples.

Biocompatibility of CS-PPy nanocomposites and their application to glucose biosensor.

The intrinsic properties and application potential of nanocolloids are mainly determined by size, shape, composition, and structure. In this case, a novel glucose biosensor was developed by using the chitosan-polypyrrole (CS-PPy) nanocomposites as special modified materials that coating onto the surface of glassy carbon electrode (GCE). The CS-PPy nanocomposites were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. Moreover, the interaction of CS-PPy nanocomposites with glucose oxidase (GOD) was also investigated by the combined studies with Fourier transform infrared spectroscopy (FTIR) and circular dichroism spectroscopy (CD). Due to the conductivity of polypyrrole (PPy), good biocompatibility of CS, and advantages of nanoparticles, CS-PPy nanocomposites were chosen and designed to modify the GCE for the retention of GOD's biological activity and the vantage of electron transfer between GOD and electrodes. The GOD biosensor exhibited a fast amperometric response (5s) to glucose, a good linear current-time relation over a wide range of glucose concentrations from 5.00×10(-4) to 1.47×10(-1)M, and a low detection limit of 1.55×10(-5)M. The GOD biosensor modified with CS-PPy nanocomposites will have essential meaning and practical application in future that attributed to the simple method of fabrication and good performance.