Automatic Calibration of Frequency Compensation System in Computer-Controlled Patch-Clamp Amplifier

Computer-controlled patch-clamp amplifier is a digitally controlled analog device used to record the cellular ion channel currents in electrophysiology research. The inherent bandwidth and performance of the headstage is limited by the stray capacitance and distributed capacitance across the feedback resistors. In order to effectively improve the performance of the headstage, the paper advanced a simplified automatic calibration method of frequency compensation system in resistor-feedback patch-clamp amplifier. The dynamic model of headstage was approximate as a two poles and one zero system in the transfer function by experience and test results, so the dynamic characteristics of the headstage were obtained employing least squares parameter estimation algorithm. Further more, the compensation parameter of high frequency booster can be estimated by the time constant of main pole of headstage. And automatic adjustment of the parameters in transient response correction stage was performed as a least squares fitting problem. The software routine running on the host computer conducted all operations of frequency compensation. Experimental results demonstrate that the simplified automatic calibration method can substantially extend the bandwidth and minimize step response error of headstage.

[1]  Lennart Ljung,et al.  System Identification: Theory for the User , 1987 .

[2]  B. Sakmann,et al.  Single-channel currents recorded from membrane of denervated frog muscle fibres , 1976, Nature.

[3]  F. J. Sigworth,et al.  Design of the EPC-9, a computer-controlled patch-clamp amplifier. 2. Software , 1995, Journal of Neuroscience Methods.

[4]  Gang Hu,et al.  Designing a Signal Conditioning System with Software Calibration for Resistor-feedback Patch Clamp Amplifier. , 2005, Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference.

[5]  INSTRUMENTATION FOR MEASURING BIOELECTRIC SIGNALS FROM CELLS , .

[6]  F. Sigworth.  Design of the EPC-9, a computer-controlled patch-clamp amplifier. 1. Hardware , 1995, Journal of Neuroscience Methods.

[7]  Design of the EPC-9 , a computer-controlled patch-clamp amplifier . 1 , 2003 .

[8]  H. A. Alzaher,et al.  Digitally tuned analog integrated filters using the R-2R ladder , 2000, ICECS 2000. 7th IEEE International Conference on Electronics, Circuits and Systems (Cat. No.00EX445).

[9]  F. Sigworth.  Electronic Design of the Patch Clamp , 1983 .

[10]  B. Sakmann,et al.  Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches , 1981, Pflügers Archiv.