ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
A highly sensitive system for producing and time-resolving small-signal current transients in bilayer lipid membranes separating two ionic solutions is described. The circuitry can be constructed from inexpensive and readily obtainable electronic components, and may be interfaced with a variety of digital oscilloscopes or data acquisition systems. The system consists of a driver, fast nanoammeter, and timing sequencer. The driver is capable of delivering a stable, very low impedance voltage pulse (−2.0 to +2.0 V) superimposed on a clamping voltage adjustable within the same range. The pulse can be of any width between 500 μs and 5000 s, and can be delayed with respect to an oscilloscope synchronization trigger, which is also provided. The nanoammeter is accurate between 10 pA and 100 mA and has a time resolution of better than 10 μs. The driver and nanoammeter were designed specifically to be stable under the conditions of a highly capacitive load with very high dc resistance, as is typical of a bilayer lipid membrane. The system can be used with either reference or blocking electrodes. Ideal and actual membrane transient response curves, along with noise assessment data, are provided for calibration purposes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1145095
