Langmuir and Langmuir-Blodgett films from adsorbed Glucose Oxidase enzymes

Abstract Blood glucose (BG) concentration is a critical biomarker for the diagnosis and management of diabetes, necessitating the development of efficient detection methods due to the high global mortality associated with the disease. Glucose oxidase (GOx) is commonly employed in fabricating electrochemical BG sensors, with numerous generations of sensors utilizing this enzyme. This study presents a novel approach to preparing a sensing layer using GOx within a Langmuir-Blodgett (LB) film deposition system. Water-soluble GOx molecules, dissolved in the aqueous subphase, exhibit surface activity and generate surface pressure upon adsorption at the air-water interface. Subsequently, a fluorescently labeled phospholipid, DPPE-NBD, is introduced to form an insoluble monolayer (Langmuir film) at the interface. GOx penetrates this layer due to electrostatic and steric interactions, further increasing surface pressure. This nanoscale composite structure is then transferred onto a solid substrate as a monolayer using the LB method. This approach offers two key advantages over conventional deposition techniques: forming a nano-thin, uniform layer—crucial for rapid sensing—and enhanced enzyme protection against environmental degradation. The study reports the successful fabrication and characterization of these GOx-based monolayers, underscoring their potential for application in BG sensing technologies.