Overview intr ace l lula Patch clamping is
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Overview intr ace l lula • Patch clamping is the I r premier method for assaying ion channel Rs ea activity – but suffers l low throughput! Rc ha • A high resistance seal e xtra nn is necessary to e c l e accurately measure llula currents through the r channel. • Our system replaces glass pipettes with Ag/Ag. Cl electrodes in a PDMS device for parallel measurements • Multiplexing is used to share a single amplifier across of many cells. all recording channels. © 2005 University of California Prepublication Data Spring 2005
Original Setup Dagan PC-One Amplifier Patch Clamp Array with PCB Control Lab. VIEW Software © 2005 University of California Prepublication Data Spring 2005
Time Division Multiplexed Configuration CAT 5 ethernet Input Cable Shielded coax output cable T Analog Devices ADG 60 4 Low leakage analog mux Noise reducin g ferrite beads Noise reducing capacitors © 2005 University of California Prepublication Data Spring 2005
Expanded Setup with Pressure Control Board Dagan PC-One Amplifier Patch Clamp Array with PCB Control Cole Parmer Pressure Controller Ambient (Air) Lab. VIEW Software © 2005 University of California Prepublication Data Spring 2005
Pressure Control Features / Advantages • Replaces manually operated syringe with valves for automated cell trapping. • Three-way valve switches between air (ambient) and negative pressure (suction). • Valve switching takes place through software (under user control), or automatically, using feedback of seal resistance measurement. • 45 Megaohm seal resistance threshold set to detect trapped cell. • Minimizes cell disruption / disturbance. © 2005 University of California Prepublication Data Spring 2005
Pressure Control System A 0 Schematic A 1 Clock Generation Circuitry Data Storage / Latches Valve Drivers Control Line 1 driver per valve © 2005 University of California Prepublication Data Spring 2005
Pressure Control Lab. VIEW Software • Flowchart for automated or manual operation of valves for cell trapping. © 2005 University of California Prepublication Data Spring 2005
