Biosensor based on Langmuir-Blodgett film with alcohol oxidase enzyme

The work examined the sensor properties of a biofilm based on phospholipid molecules 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine with immobilized molecules of the enzyme alcohol oxidase to vapors of ethyl and isopropyl alcohols. The immobilization of alcohol oxidase enzyme molecules was carried out using a Langmuir monolayer process of phospholipid molecules. The sensor coating was obtained using the Langmuir-Schaeffer technology, in which the substrate is oriented parallel to the monolayer. The analysis of microimages of the film surface obtained by atomic force microscopy, allows to present of enzyme molecules in it was established. The study of the sensory properties of the formed coatings was carried out using acoustoelectronic technology. The presence of the enzyme in the sensor coating led to an increase in the amplitude and phase responses of the acoustic delay line when interacting with vapors of the detected substance. The maximum amplitude and phase responses were recorded when the film interacted with ethanol vapor and were 1.5 dB and 19°, respectively. The work showed that the formed sensor coating has selective sensitivity to ethanol vapor. This allows us to conclude that it is possible to use this sensor coating to create an acoustoelectronic ethanol biosensor. Increasing the sensitivity of such biosensors can be achieved by varying technological parameters such as the number of layers in the film, as well as the amount of immobilized enzyme in each layer.