Plasmonic Heating of Gold Nanoparticles for Controlling of Current Across Lipid Membranes in Modulating Neuronal Behavior Applications Mir Hossein seyed Nazari 1 , Ahmad Ghorbani 1 , Faezeh Akbari 1 , Javad Fahanik Babaei 2 , Afsaneh Eliassi 2 , Leila Dragahi 3 , and Hamid Latifi 1 , Mohammad Ismail Zibaii 1 1. Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran 2. Neuroscience Research Center and Department of Physiology, Shahid Beheshti University of Medical Sciences, Evin, Tehran, Iran 3. Neuroscience Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran Electrophysiology is a golden method for the study of the nervous system. However, electrical stimulation has to deal with multiple challenges, including selectivity, spatial resolution, mechanical stability, and implant- induced injury. Optical stimulation techniques may avoid some of these challenges by providing more selective stimulation, higher spatial resolution and reduced invasiveness of the device. Optogenetics is a technique to introduce light-sensitive ion channels to neurons for optical stimulating of them with tight spatial and temporal confinement. While optogenetics provides a powerful tool for studying neural functions, the main limitation for clinical applications is gen expiration. One current status of the optical stimulation technique is using nanoparticles (NPs) for temperature manipulation of neural cells at the nanoscale. Nanoabsorbers like gold nanoparticles (AuNPs) when irradiated at their plasmon resonance, AuNPs heat up rapidly and confer this heat to the plasma membrane. Laser irradiation of light-absorbing AuNPs transiently increases cell membrane permeability [1]. Here, we present an investigation of the interaction patterns of AuNPs with diameters from 10 and 50 nm with artificial membranes which local plasmonic heating of AuNPs can be utilized to regulate membrane currents and conductance situations of membranes. In this study, the black lipid membrane (BLM) as an artificial planar lipid membranes were used. BLM experiments were accomplished using a small Teflon chamber with two compartments (cis and trans) are separated by a small aperture onto which the lipid bilayer membrane is formed. The compartments are each filled with a different concentration of KCl as an electrolyte solution. The membrane current (I) was measured through silver/silver-chloride electrodes inserted into the aqueous salt solutions on both sides of the membrane, using a current-to-voltage converter[2]. To study the effects of NPs with different sizes on the cell membranes, the diphytanoyl-phosphatidylcholine (DiphPC) lipid were selected as bilayer membranes. AuNPs with different sizes and concentrations were always added to the cis- side of the membrane. AuNPs were plunged into the solution after a short time a laser with a wavelength of λ = 532 nm was focused on the hole. The laser power for all experiment was set to be 50 mW. In our experiments, light sources consist of both continuous and pulse irradiations. The obtained results show the amount of current that flows through a bilayer membrane was 17 and 10 pA for a continuous and pulse irradiation to the NPs with size 50 nm, respectively. While in the same experimental conditions heating of NPs with the size 10 nm leads to the current pass of membrane equal to 12 and 8pA, respectively. Fig. 1 (a) Schematic of experimental setup, and (b)changing of current pass of membrane with laser illumination In this configuration, the attendance of AuNPs and their successful heating is indirectly approved by evaluating an increase of the membrane current after laser irradiation. In conclusion, we have indicated that local heating can be utilized to control the permeability of lipid membranes. This method of controlling biological systems and cellular function with high spatio-temporal resolution can be used control cell function [1], modulation of electrical activity and nerve regeneration [3]. References 1 P.Urban, Silke R. Kirchner, C. Mühlbauer, T. Lohmüller, and J. Feldmann, “Reversible control of current across lipid membrane s by local heating,” Sci. Rep. 6, 22686 (2016). [2] J. Broda, J. Setzler, A. Leifert, J. Steitz, R. Benz, U. Simon, W. Wenzel, “Ligand-Lipid and Ligand-Core Affinity control the Interaction of Gold Nanoparticles with Artificial Lipid Bilayers and Cell Membranes,” Nanomedicine. 12(5),1409-19 (2016). [3] C. Paviolo and P. R. Stoddart “Review: Gold Nanoparticles for Modulating Neuronal Behavior,” Nanomaterials, 7, 9(2017).