Researchers develop neighborhood nanostructure biosensing membranes

Glucose detection and real-time continuous monitoring are essential for the diagnosis and prevention of diseases such as diabetes, as well as controlled production during sugar refining and fermentation. In this process, glucose biosensing equipment with glucose oxidase, Prussian blue, and electrodes as the core is very promising.

Recently, the State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences has developed a new three-dimensional mesoporous biosensing membrane with neighborhood nanostructure, which greatly improves the sensing area area, Prussian blue utilization rate and substrate accessibility to the sensing area in glucose biosensing equipment, with excellent sensitivity and long-term stability. The work was published in Advanced Functional Materials.

Due to the fast formation rate and easy agglomeration of Prussian blue, its synthesis and distribution on the electrode are difficult to control, resulting in high-density disorderly accumulation of Prussian blue, forming a layer-by-layer distribution sensing structure with small sensing area, low utilization rate and large steric hindrance, low sensing sensitivity and poor stability.

Inspired by the electron transport chain structure on the cell membrane, a schematic diagram of a three-dimensional mesoporous biosensing membrane with a neighborhood nanostructure was developed. (Photo courtesy of the research team)

In view of the above problems, the team of Wan Yinhua, a researcher at the State Key Laboratory of Biochemical Engineering of the Institute of Process Engineering, used a ternary coating of tannin-3-aminopropyltriethoxysilane-iron (TA-APTES-Fe) as a structural guiding agent to regulate the immobilization position and assembly rate of Prussian blue, and fixed Prussian blue and glucose oxidase adjacent to each other in three-dimensional mesoporous carbon nanotubes (CNTs) membrane electrodes through coordination and covalence respectively to prepare mesoporous biosensing membranes with neighborhood nanostructures.

Compared with the layer-by-layer longitudinal biosensors, the new sensing membrane expands the sensing area from a two-dimensional plane into a three-dimensional mesoporous membrane electrode, thereby improving the utilization rate of Prussian blue and the accessibility of glucose and hydrogen peroxide to the sensing area. At the same time, this structure shortens the distance between the cascade sensing units, thereby shortening the diffusion distance of hydrogen peroxide to the sensing interface, effectively inhibiting the diffusion of hydrogen peroxide into the main solution, and reducing its ineffective dissipation. The experimental data show that the new sensing membrane has high sensitivity in the flow mode, and can stably and continuously monitor the glucose concentration in sucrose juice for up to 8 hours without current response drift.

In view of the problem of biosensor contamination, based on the pH response multi-enzyme activity of Prussian blue, the research team proposed to use the glucose oxidase-Prussian blue cascade to generate microbubbles and Fenton oxidation in turn to simulate the “loose-degradation” membrane cleaning process, and the shear effect brought by the microbubbles generated in situ helps loosen the contaminated layer on the surface of the membrane, thereby increasing the accessibility of free radicals to pollutants, so as to realize the self-cleaning of the contaminated biosensing membrane.

Siqing Song, a 2022 master’s graduate of the Institute of Process Engineering, is the first author of the paper, and assistant researcher Zhang Hao and researcher Luo Jianquan are co-corresponding authors. This work was supported by the National Key Research and Development Program of China and the National Natural Science Foundation of China. (Source: China Science News Gan Xiao)

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