CONICET | Buscador de Institutos y Recursos Humanos

Biological membranes are an important interface in cells, particularly due to they hold transmembrane proteins involved in mechanisms of signal transduction,regulate the entry and exit of matter in the cell, etc. To study these processes, biomimetic systems mimicking biomembranes have been developed1.Transmembrane protein anchoring on immobilized lipid layers on conductivesubstrates allows to analyze the interaction of these proteins with the membrane,and also opens the possibility of using these systems as a platform for biosensors that respond to electrochemical stimuli. In this work, we studied the insertion and function of the nicotinic acetylcholine receptor (nAChR) in Au(111)- supported bilayers. The biomimetic system was formed by incorporating nAChR into an Au(111)-supported thiolipid self-assembled monolayers (SAMs) and forming a 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) layer on the nAChR-containingSAM. We used AFM to characterize the supported bilayer and electrochemical techniques to analyze the functionality of the inserted protein. Electrochemical results show that the surface of Au (111) is coated with the thiolipid monolayer,decreasing the capacity of the double layer2. This capacity is maintained after the insertion of nAChR and decreases after DMPC layer formation, but increases with the addition of the agonist Carb, due to the opening of the intrinsic ion channel of nAChR protein3. Moreover, our results suggest that the channel aperture induced by Carb is inhibited by anesthetics since the double layer capacitance is further reduced after the addition of lidocaine hydrochloride. Thus, the system appears to be a viable biomimetic model to measure ionic conductance mediated by iongated ion channels under different experimental conditions, with potential applications in biotechnology and pharmacology.