An innovative electrochemical immuno-platform towards ultra-sensitive monitoring of 2-arachidonoyl glycerol in samples from rats with sleep deprivation: bioanalysis of endogenous cannabinoids using biosensor technology

Abstract

The endocannabinoid system (ECS) is a complex of neurotransmitters in the central nervous system and plays a key role in regulating cognitive and physiological processes. 2-Arachidonoylglycerol (2-AG) is one of the imperative endocannabinoids that play key roles in the central nervous system. It acts as a signaling lipid and activates the cannabinoid CB1 receptor. In addition, 2-AG is involved in a variety of physiological functions such as energy balance, emotion, pain sensation, cognition, and neuroinflammation. So, rapid and specific diagnosis of 2-AG is of great importance in medical neuroscience. The development of new methods in this area has been one of the most important research areas in recent years. Herein, an innovative immunosensor is developed for quantification of 2-AG. For this means, gold nanostars (GNS) were synthesized and conjugated with a specific biotinylated antibody against 2-AG. The resultant bioconjugate, a bioreceptor with GNS, was immobilized on the surface of a gold electrode and used for the detection of the antigen based on the immunocomplex formation followed by analysis using different electrochemical techniques. For the first time, 2-AG protein was measured with an excellent linear range of 0.48–1 ng mL⁻¹ and lower limit of quantification of 0.48 ng L⁻¹ by the electroanalysis method. The engineered immunosensor showed high sensitivity and specificity in the presence of interfering antigens, proving its utility in neurological disorder detection. This immunosensor is the first sandwich type immunoassay for the detection of 2-AG in real samples and the first innovation of designing a novel sandwich type immunosensor for this analyte. Also, excellent analytical results are other advantages of this biosensor for the detection of 2-AG in human plasma samples and serum samples of rats under sleep deprivation. So, this is the first report of an immunosensor of 2-AG using a sandwich type immunosensor.