Langmuir–Blodgett Films with Immobilized Glucose Oxidase Enzyme Molecules for Acoustic Glucose Sensor Application

Abstract

In this work, a sensitive coating based on Langmuir–Blodgett (LB) films containing monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) with an immobilized glucose oxidase (GOx) enzyme was created. The immobilization of the enzyme in the LB film occurred during the formation of the monolayer. The effect of the immobilization of GOx enzyme molecules on the surface properties of a Langmuir DPPE monolayer was investigated. The sensory properties of the resulting LB DPPE film with an immobilized GOx enzyme in a glucose solution of various concentrations were studied. It has shown that the immobilization of GOx enzyme molecules into the LB DPPE film leads to a rising LB film conductivity with an increasing glucose concentration. Such an effect made it possible to conclude that acoustic methods can be used to determine the concentration of glucose molecules in an aqueous solution. It was found that for an aqueous glucose solution in the concentration range from 0 to 0.8 mg/mL the phase response of the acoustic mode at a frequency of 42.7 MHz has a linear form, and its maximum change is 55°. The maximum change in the insertion loss for this mode was 18 dB for a glucose concentration in the working solution of 0.4 mg/mL. The range of glucose concentrations measured using this method, from 0 to 0.9 mg/mL, corresponds to the corresponding range in the blood. The possibility of changing the conductivity range of a glucose solution depending on the concentration of the GOx enzyme in the LB film will make it possible to develop glucose sensors for higher concentrations. Such technological sensors would be in demand in the food and pharmaceutical industries. The developed technology can become the basis for creating a new generation of acoustoelectronic biosensors in the case of using other enzymatic reactions.

Recent Progress in the Applications of Langmuir–Blodgett Film Technology

“…Subsequently, Kuo et al [ 62 ] prepared Ag nanocrystalline LB films for the detection of glucose in surface-assisted laser desorption/ionization mass spectrometry (SALDI MS), which was found to have the highest signal intensity, high sensitivity, and good reproducibility. Gorbachev et al [ 63 ] used the LB technique to prepare an immobilized glucose oxidase (GOx) with 1,2-dipalmitoyl-stannous-glycerol-3-phosphoethanolamine (DPPE) monolayer film and found that the immobilization of GOx enzyme molecules on LB DPPE films increased the conductivity of LB films with increasing glucose concentration, making it possible to develop glucose sensors for higher concentrations. With the use of other enzymatic reactions, the developed technology could be the basis for creating a new generation of acousto-electronic biosensors.…”