Ion Channels as Natural NanoDevices 1 Project Goals: Develop measurement, simulation, and fabrication tools needed to make ion channels into practical devices that can be controlled for our use. Technical Approach –Measure currents from single protein molecules of known and modified ATOMIC structure, in a wide range of solutions –Compare measurements with currents predicted from mean field theories and transport Monte Carlo, so we understand the PHYSICAL BASIS OF SELECTIVITY and permeation. –Fabricate sheets of channels as strong as SaranWrap that generate microamps of signal. Channel Sheets might be the silicon wafer of ionic transistors. Porins Gramicidin

Cl ChannelAgonist Channel Ion Channels as Natural NanoDevices 2 Technical Approach –Compare measurements with currents predicted from mean field theories and transport Monte Carlo, so we understand the PHYSICAL BASIS OF SELECTIVITY and Permeation. Calcium Channel Na Channel

Figure from Mashl/Jakobsson rSingle molecule detection rPower of protein engineering rCurrent flow changed by binding rFrequency reveals concentration rAmplitude reveals identity rDurable only in lab setting rBiomimetics: Functionality of ion channels into nanopores (CNTs) rIdeal for IC based chips rFundamental issues: Transport of water, electrolytes and analytes through CNT Ion Channels, Nanopore Sensors, Aluru et al 3

Nature 414, (2001) Our Simulations Occupancy of Water in SWCNT 4

Drift-Diffusion Simulation with Prophet 5 Umberto Ravaioli et al It is straightforward to include several multi-valent species in PROPHET without modifying the source-code. Example: CaCl 2 in ompF porin

Monte Carlo Particle Simulation of Channels 6 Umberto Ravaioli et al Gramicidin - Successful Na + trajectory – Point particle model The charged particle trajectories are evaluated from a detailed electric field distribution in space, obtained by solving the Poisson equation.

Ion Channels as Natural NanoDevices 7 Technical Approach –Fabricate sheets of channels as strong as SaranWrap that generate microamps of signal. Channel Sheets might be the silicon wafer of ionic transistors.