HumSilencer Technology




A Common Patch-Clamp Problem

50/60 Hz line-frequency noise, also known as electrical hum, is the most common source of background noise in patch-clamp electrophysiology experiments. Originating from alternating current (AC) of the electrical mains and delivered via power outlets, this noise can often overwhelm biological signals of interest, making sensitive current or voltage measurements nearly impossible (Figure 1).

Typical troubleshooting can be time-consuming and only partially effective as researchers need to identify and either eliminate or shield noise source. While notch or off-line filtering methods can be employed, often these filter-based methods do not fully remove electrical noise, and in some situations can actually distort biological signals and impair data accuracy.

(Fig. 1). Electrical hum overwhelming a single-channel recording of the principal subunit of olfactory cyclic nucleotide-gated channel (CNCA2). Data courtesy of Tsung-Yu Chen, Ph.D., University of California, Davis.

The Solution: HumSilencer Technology

The HumSilencer™ technology available in Axon™ Digidata® 1550B Low Noise Data Acquisition System is a filter-free, adaptive technology that learns and removes local line-frequency noise patterns from incoming signal in less than one second (Figure 2).

Caption(Fig. 2). With HumSilencer enabled, accurate signal measurements of CNCA2 can be obtained (top). Raw data is  shown in Figure 1 and is repeated at the bottom. Data courtesy of Tsung-Yu Chen, Ph.D., University of California, Davis.


  • Filter-free noise elimination means no signal distortion such as frequency change, amplitude attenuation, phase shift, or DC voltage change

  • HumSilencer is accessed through Axon pCLAMP™ or Axoscope™ software and can be turned on or off with a single click. No extra hardware is required!

  • Learns and adapts to changing noise profiles within one second. Eliminates up to 20 V amplitude at the digitizer's analog input.


Extracellular field potential recordings

(Fig. 3). HumSilencer enables accurate measurement of extracellular field potential recordings of CA1 pyramidal cell body layer of a mouse hippocampus brain slice. Top = HumSilencer-enabled data;bottom = raw data. 
Data courtesy of John Huguenard, Ph.D., Stanford University

Whole-cell recordings

(Fig. 4). HumSilencer enables accurate single measurement in whole-cell recordings from a C. elegans body-wall muscle cell. Top = HumSilencer-enabled data; bottom = raw data.
Data courtesy of Zhao-Wen Wang, Ph.D., University of Connecticut Health Center.

Macroscopic currents from excised patches

(Fig. 5). HumSilencer enables accurate measurement of macroscopic currents from patches excised from an HEK cell at -80V holding and repolarizing potentials. Top = HumSilencer-enabled data; bottom = raw data. Data courtesy of Huanghe Yang, Ph.D., University of California, San Francisco.

HumSilencer does not distort current-induced action potentials

(Fig. 6). HumSilencer does not distort current-induced action potentials, which were evoked by injecting a depolarizing current pulse into the recorded muscle cell. Top = HumSilencer-enabled data; middle = raw data; bottom = injected current pulse at 100 nA magnitude and 100 ms duration. Data courtesy of Andrew Voss, Ph.D., Wright State University.

Patch and Record Cellular Network Noise-Free

Equipped with up to four analog HumSilencer inputs, the Digidata 1550B System enables you to record multiple cells at once for cellular network studies without 50/60 Hz line-frequency noise.

For more information, please visit the Digidata 1550B page or download our HumSilencer application notes.

Recording with 4 model cells. Black traces: raw data; red traces: same data with HumSilence enabled.