Synthesis, characterization, and application of gold nanostars for the identification of 2-Arachidonoyl glycerol

Background. The endocannabinoid system (ECS) is a complex of neurotransmitters in the central nervous system (CNS) and plays a key role in regulating cognitive and physiological processes. Also, 2-Arachidonoylglycerol (2-AG) is one of the imperative endocannabinoids with key roles in the CNS. 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. Hence, rapid and specific diagnosis of 2-AG is of great importance in medical neuroscience. Routine methods used in detection of 2-AG are not sensitive and specific. Therefore, the development of new methods in this area has been one of the most important research areas in recent years. Methods. Herein, an innovative immunosensor was developed for quantification of 2-AG. To this end, gold nanostars (GNSs) were synthesized and conjugated with a specific biotinylated antibody activated by EDC/NHS against 2-AG. The resultant bio-conjugate was immobilized on the gold electrode surface and used to detect and analyze 2-arachidonylglycerol antigen by cyclic voltammetry (CV), square wave voltammetry (SWV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy techniques. Results. For the first time, 2-AG protein was measured with an excellent linear range of 0.00048-1 ng/L and lower limit of quantification of 0.00048 ng/L by electroanalysis method. The designed immunosensor showed high sensitivity and specificity in the presence of interfering antigens, which proved its appropriate use in the diagnosis of neurological disorders. Conclusion. The remarkable achievement of the present study is the development of a new immunosensor for the sensitive and accurate detection of 2-AG. The fabricated sensor substrate showed good analytical results for the target analyte. Regardless of the appropriate sensitivity and selectivity of the designed biosensor, the stability of the sensor is low and it is recommended to use it immediately after preparation. Also, the immunosensor engineered in this research was very economical and had a very fast and good performance compared to the usual and traditional methods for detecting 2-AG. Practical Implications. For the first time, 2-AG protein was measured with an excellent linear range of 0.00048-1 ng/L and lower limit of quantification of 0.00048 ng/L by electro analysis method. The designed immunosensor showed high sensitivity and specificity in the presence of interfering antigens, which proved its appropriate use in the diagnosis of neurological disorders.