Сенсорное покрытие на основе липидного ленгмюровского монослоя с молекулами фермента глюкозооксидазы

Abstract

A sensor coating was created based on a Langmuir monolayer of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) with immobilized molecules of the enzyme glucose oxidase and its sensor properties were studied. The process of incorporation of glucose oxidase enzyme molecules into a Langmuir monolayer of phospholipid DPPE molecules was studied using the compression isotherm method. Adsorption of glucose oxidase molecules has an expanding effect on the Langmuir monolayer of DPPE and leads to an increase in the area per molecule from 32.5 Å2 to 49 Å2 and a decrease in the compression modulus of the monolayer from 133 mN/m to 83 mN/m. Also, the adsorption of glucose oxidase leads to an increase in the desorption coefficient of the monolayer into the kd subphase from 0.5·10-3 to 1.2·10-3. The morphology of films with immobilized enzyme molecules at different adsorption times was characterized by atomic force microscopy. Increasing the enzyme adsorption time leads to a decrease in the surface roughness of the formed film from 3.6 nm at 5 minutes to 2.4 nm at 60 minutes. The formed DPPE monolayers with immobilized enzyme molecules were transferred to graphite electrodes. Their sensory properties were studied using cyclic voltammetry and impedance measurements. The resulting coatings were sensitive to glucose in solutions with concentrations from 0 to 1 mg/ml. The presence of a linear concentration dependence of the maximum and minimum currents and resistances in the specified concentration range makes the created films promising for use as touch coatings.