Automatic patch clamp

These are automatic patch clamp algorithms adapted from the literature.

Main patch clamp algorithm

Amplifier start-up (on Multiclamp 700B):

  1. Voltage-clamp.

  2. Disable resistance metering and pulses.

  3. Compensate pipette (slow and fast).

  4. Set pulse amplitude and frequency (default 1e-2 and 1e-2, units unclear).

  5. Set zap duration at 1 ms.

  6. Do pipette offset (V=0).

  7. Set holding potential V = 0.

  8. Enable resistance metering (triggers voltage pulses).

Resistance check: 1. Set pressure at pressure_near (>0). 2. Do pipette offset (V=0) and wait for 4 s. 3. Check that the resistance is within specified bounds.

Approach:

  1. Move the manipulator with a safe move to a distance cell_distance above the target position, if specified.

  2. Do pipette offset and wait for 2 s.

  3. Check that resistance has not increased by 1+cell_R_increase.

  4. Move down by 1 µm and wait for 1 s (maximum total movement max_distance).

  5. Measure R. Unless R has increased by 1+cell_R_increase, repeat (7).

Sealing:

  1. Release the pressure and wait for 10 s.

  2. If R is smaller than 1+cell_R_increase times R: go back to approach (7). Note that pressure is now released.

  3. Set pressure at pressure_sealing (<0).

  4. If R>gigaseal_R: success (next stage).

  5. Ramp V down to Vramp_amplitude (default -70 mV) over duration Vramp_duration.

  6. Wait for at least seal_min_time, and until R>gigaseal_R (success) or time is out (seal_deadline) (failure).

  7. Success or failure: release pressure.

Break-in:

  1. If R<gigaseal_R: failure (seal lost).

  2. Increase max pressure by pressure_ramp_increment; fail if greater than pressure_ramp_max.

  3. If zap is True, do an electric zap.

  4. Do a pressure ramp up to max pressure, of duration pressure_ramp_duration; wait for 1.3 s.

  5. If R<max_cell_R: success.

Ending (also if stopped in the middle):

  1. Stop the amplifier: disable resistance metering and pulses; current-clamp.

  2. Set the pressure at pressure_near (>0).