• Alpha-Hemolysin

    Event-averaged histograms (black) and overlaid current traces (blue) of parallel and simultaneous recordings on the Orbit 16.


Pore-forming Toxins

Members of this family are proteins/peptides, synthesized by one cell and secreted for insertion into the membrane of another cell where they form transmembrane pores. Pore-forming toxins (PFTs) are the most common bacterial cytotoxic proteins and are required for virulence in a large number of important pathogens.

Over 100 subgroups belong to the "Pore-forming Toxins" family, including amongst others:

  • The α-Hemolysin Channel-forming Toxin (αHL) Family
  • The Aerolysin Channel-forming Toxin (Aerolysin) Family
  • The Botulinum and Tetanus Toxin (BTT) Family
  • The Pertussis Toxin (PTX) Family
  • The Crystal Protein (Cry) Family

Alpha-Hemolysin Background Information


Alpha-hemolysin, also called Alpha-toxin, is secreted by Staphylococcus aureus. It binds to the membrane of eukaryotic cells (particularly red blood cells, RBC and formes pores, resulting in hemolysis. This toxin causes cell death by binding with the outer membrane.

Data Sheet:


UniProt: P09616 (Staphylococcus aureus)

Alpha-hemolysin forms a homo-heptameric β-barrel in biological membranes.

The secreted monomeric species associates with animal cell membranes to form a 232 kDa homoheptameric transmembrane β-barrel pore that promotes cell death by allowing bilayer permeability to ions, water and small solutes, thereby promoting cell lysis. αHL forms a solvent-filled channel with a length of 100 Å.

Bilayer Recordings on the Orbit Product family

Reviews and Links

Data and Applications

Alpha-Hemolysin - Parallel Recordings of monoPEG-28 Block

2011 HemolysinIcon Orbit   Orbit 16 data and applications: 
Data courtesy of Dr. Gerhard Baaken et. al., University of Freiburg / Ionera.

Event-averaged histograms (black) and overlaid current traces (blue) of parallel and simultaneous recordings on a MECA chip of monoPEG-28-mediated blockages of hemolysin nanopore(s). The current traces were recorded with a multichannel amplifier (Tecella Jet 16). Histograms were derived from the mean current levels of at least 2000 visits of blocked stated per cavity (20 kHz sample frequency).
Read the full paper. (Am. Chem. Soc Nano, 5(10), 8080-8088, 2011)

Alpha-Hemolysin - DNA Translocation

p45 4 AlphaHemolysinNeu icon pap   Port-a-Patch and   icon vpp   Vesicle Prep Pro data and applications:

Data were kindly supplied by Prof. Fritz Simmel, Technical University of Munich, Munich, Germany.

Reconstituted Alpha hemolysin channels are constantly open at positive and negative membrane potentials. Gating is observed as a result of the passage of a single stranded DNA molecule through the pore. Recordings were performed on the Port-a-Patch.

Alpha-Hemolysin - Block by Mono- and Poly PEGs

Icon Orbit   2011 HL HistOrbit 16 data and applications:
Data courtesy of Dr. Gerhard Baaken et.al, University of Freiburg / Ionera.

Current traces and histograms derived from recordings of αHL pores blocked by monoPEG-28 and polyPEG-1500 on an Ionera MECA chip (AxoPatch 200B, filter freq: 20kHz, digitized at 200 kHz).
Read the full paper: (Am. Chem. Soc Nano, 5(10), 8080-8088, 2011)

Alpha-Hemolysin - Automated Formation of Membranes from Polyoxazoline based Triblock Copolymers

Icon Orbit   Orbit16 Ionera ahemolysin 2Orbit 16 and applications:
Data were kindly provided by Ionera.

Automated formation of membranes from polyoxazoline based triblock  popolymers. Screenshot of a recording of Alpha-Hemolysine in a polyoxazoline based triblock copolymer membrane on the Orbit 16.

Alpha-Hemolysin is capable of insertion into triblock copolymer membranes.
(A) Current-voltage relationship of Alpha-Hemolysin pore in Poly(2-methyloxazoline-b-dimethylsiloxane-b-2-methyloxazoline) membrane. Average of two channels. Conditions: 25 mM Tris, 4 M KCl, pH 8.0.
(B+C) Representative recordings of Alpha-Hemolysin with PEG-28 at 40 mV and -40 mM. Conditions: 25 mM Tris, 4 M KCl, pH 8.0. Note different time scale at positive (B) and negative (C) potentials. 

Alpha-Hemolysin - Temperature Control

Icon Orbit Mini   temperature control OrbitOrbit mini and applications:
Data were kindly provided by Ionera.

Temperature control of the Orbit mini: PEG induced current blockages of a alpha-hemolysin pore

(A) Current traces recorded at 10°C and 40°C illustrating a strong increase of the open pore current as well as the blockage frequency at elevated temperature.
(B) Event averaged histograms of the residual current during blockages. The open pore current scales with the temperature as well as the dwell time of the blockages.
(C) Dependence of the open pore current on the temperature.
(D) Dependence of the frequency of blockages on the temperature.

Alpha-Hemolysin - PEG Detection

Icon Orbit   Orbit16 Ionera ahemolysinOrbit 16 and applications:
Data were kindly provided by Ionera.

Screenshot of the recording window showing simultaneous and parallel PEG detection with single aHL-nanopores. Channels 1-5,7,12-14 contain a single aHL-nanopore. Channels 10 and 11 have two and Channel 9 has three aHL-nanopores. In Channels 8 and 14 single aHL-nanopores are assembled as hexamer. Channels 6 and 16 are switched off.
Conditons: 3 M KCl, 20 mM TRIS, pH 8, +40 mV

Application Notes


2019 - A comparison of ion channel current blockades caused by individual poly(ethylene glycol) molecules and polyoxometalate nanoclusters

Icon Orbit   Orbit 16 publication in The European Physical Journal E (2019)

Wang H., Kasianowicz J.J., Robertson J.W.F., Poster D.L., Ettedgui J.

2018 - Size-dependent interaction of a 3-arm star poly(ethylene glycol) with two biological nanopores

Icon Orbit   Orbit 16 publication in The European Physical Journal E (2018)

Talarimoghari M., Baaken G., Hanselmann R., Behrends J.C.

2018 - Cell‐free production of pore forming toxins: Functional analysis of thermostable direct hemolysin from Vibrio parahaemolyticus

Icon Orbit   Orbit 16 publication in Engineering in Life Sciences (2018)

Dondapati S.K., Wüstenhagen D.A., Strauch E., Kubick S.

2016 - Probing driving forces in aerolysin and α-hemolysin biological nanopores: electrophoresis versus electroosmosis

Icon Orbit  Orbit 16 publication in Nanoscale (2016)

Boukhet M., Piguet F., Ouldali H., Pastoriza-Gallego M., Pelta J., Oukhaled A.

2015 - High-Resolution Size-Discrimination of Single Nonionic Synthetic Polymers with a Highly Charged Biological Nanopore

Icon Orbit  Orbit 16 and   icon vpp   Vesicle Prep Pro publication in American Chemical Society Nano (2015)

Baaken G., Halimeh I., Bacri, Pelta J., Oukhaled A., Behrends J.C.

2015 - Automated Formation of Lipid Membrane Microarrays for Ionic Single-Molecule Sensing with Protein Nanopores

Icon Orbit  Orbit 16 publication in Small (2015)

Del Rio Martinez J.M., Zaitseva E., Petersen S., Baaken G., Behrends J.C.

2014 - Generation of chip based microelectrochemical cell arrays for long-term and high-resolution recording of ionic currents through ion channel proteins

Icon Orbit  Orbit 16 publication in Sensors and Actuators B: Chemical (2014)

Zheng T., Baaken G., Vellinger M., Behrends J.C., Rühe J.

2012 - Synthetic Lipid Membrane Channels Formed by Designed DNA Nanostructures

Icon Orbit   Orbit 16 publication in Science (2012)

Langecker M., ArnautV., Martin T.G., ListJ., RennerS., Mayer M., Dietz H., Simmel F.C.

2012 - Natural and artificial ion channels for biosensing platforms

icon pap   Port-a-Patch,   icon pl   Patchliner,   icon sp96   SyncroPatch 96 ((a predecessor model of SyncroPatch 384PE) and   icon vpp   Vesicle Prep Pro publication in Analytical and Bioanalytical Chemistry (2012)

Steller L., Kreir M., Salzer R.

2011 - Nanopore-based single-molecule mass spectrometry on a lipid membrane microarray

Icon Orbit   Orbit 16 publication in Journal of the American Chemical Society Nano (2011)

Baaken G., Ankri N., Schuler A.K., Rühe J., Behrends C.

2008 - Planar microelectrode-cavity array for high-resolution and parallel electrical recording of membrane ionic currents

Icon Orbit  Orbit 16 publication in Lab on a Chip (2008)

Baaken G., Sondermann M., Schlemmer C., Rühe J., Behrends J.C.


27.01.2016 | Webinar: Instant bilayers - just add protein.

Icon Orbit   Orbit 16 and   Icon Orbit Mini   Orbit Mini

Orbits V1 flat 250pxThis webinar covers the use of the lipid bilayer platforms from Nanion: the Orbit16 and the Orbit mini for characterization of membrane proteins like ion channels, bacterial porins and biological nanopores. Both bilayer systems support high quality low noise recordings, but differ in throughput capabilities and experimental features. The Orbit16, introduced in 2012 is a device for efficient formation of 16 lipid bilayers simultaneously, allowing for parallel bilayer-reconstitution of ion channels and nanopores.



We use cookies on our website. Some of them are essential for the operation of the site, while others help us to improve this site and the user experience (tracking cookies). You can decide for yourself whether you want to allow cookies or not. Please note that if you reject them, you may not be able to use all the functionalities of the site.