Model 7700 Series Optopatch Patch Clamp :

The Optopatch patch clamp amplifier from Cairn Research is a general purpose amplifier, incorporating a number of unique features in order to optimize its performance across a wide range of applications. The headstage includes a patented optical technique for measuring small currents over a wide bandwidth (up to 200 KHz). A major feature is the inclusion of a lock-in amplifier for measurement of membrane capacitance and resistance, with linear calibrated resistance and capacitance outputs. This built in device has a unique "track-in" mode that keeps the lock-in amplifier in perfect balance, maintaining discrimination between resistance and capacitance, details of which have now been published in Pflügers Archiv Vol 443, pp 653-663 (2002). The Optopatch also includes unique circuitry for protection against overcompensation of series resistance and electrode capacitance, safeguarding your cells during recording.

• Single channel recording

• Whole cell recording

• High resolution capacitance measurement

• Fast, high impedance amplifier

• Voltammetry

• Optical headstage for high bandwidth and low noise

• Differential reference input on headstage

• True voltage follower in current clamp mode

• Unique cell protection against over compensation of series resistance and electrode capacitance

• Calibrated resistance and capacitance outputs

• Integral lock-in amplifier for membrane capacitance measurement

• Choice of four or eight pole Bessel filtering

• Gain and frequency telegraphing outputs

• Electrode capacitance compensation of up to 15pF

• Membrane capacitance compensation of up to 200pF with standard headstage

• High resolution metering displays

• Optional external control of many functions

The headstage uses a patented optical technique for passing current in both ranges. It has a true voltage follower mode that does not degrade the performance in other configurations, and also incorporates a differential reference input. A separate headstage is available for large membrane capacitance compensation (up to 2nF).

Schematic view of headstage

Internal view of headstage

Optical Headstage Specifications:

The patch clamp amplifier unit incorporates all the facilities expected on a modern patch clamp amplifier, with the several unique additions, including the built-in lock-in amplifier for membrane capacitance measurement and protection against overcompensation of electrode capacitance and series resistance. Additional standard features include a sine/square wave signal generator, three resistance and capacitance ranges for higher resolution, and four pole Bessel filtering. Gain and frequency telegraph outputs conform to the standards used by commercial electrophysiological software.

Episodic Data Acquisition - For high speed single channel and whole cell recordings using sweep based protocols we recommend using the Strathclyde Electrophysiology Software written by Dr. J.Dempster, together with a third party acquisition card (current recommendation is the National Instruments PCI-MIO-16E). This provides a complete versatile and economical electrophysiology system.