SURFE²R N1 - In-depth Transporter Research
In contrast to conventional patch-clamp electrophysiology, the SURFE²R (surface electrogenic event reader) technology is designed for the measurements of electrogenic transporters (symporters, exchangers and uniporters) and pumps. Usually these proteins have low turnover rates compared to ion channels. SURFE²R technology compensates for that with a large sensor size which allows for the measurement of up to 109 transporters at the same time to yield the best signal to noise ratio. The SURFE²R N1 was designed for basic research and universities. When higher throughput is required, the SURFE²R 96SE is able to measure 96 sensors in a fully parallel mode.
Features of the SURFE²R N1
• Automated recordings with up to 52 different solutions
• 150 data points per day
• All-in-one device, including liquid handling, electrophysiology hardware and computer
• Easy-to-learn, ideal for teaching
Features of SSM-based electrophysiology
• > 100 targets validated, 100 peer reviewed papers using SSM-based electrophysiology
• Transporters, pumps and ligand gated channels
• Measure even electroneutral exchangers and sugar binding
• Use purified membranes and vesicles from cells or proteoliposomes
• Label-free electrical measurements
• Requires only 0.1 – 1 µg protein per sensor. This is sufficient for up to 100 experiments.
• Real-time data with high time resolution, not single point read-out
• High signal amplification compared to patch-clamp
• Fast binding kinetics can be resolved
• EC50, IC50, rate constants, comparison of transporter variants,...
The technology employs solid-supported membrane- (SSM-) based electrophysiology which was established in the late 1990s. Details about SSM-based electrophysiology are presented in the Technology section. The reusable sensors contain a gold-coating on which the SSM is formed in a quick pipetting process. Then the sample containing your transporter of interest is added on top to physically adsorb to the SSM. Any kind of membrane preparation containing the protein of interest can be used for measurements, e.g. membrane vesicles after cell disruption or proteoliposomes after reconstitution of purified proteins. These samples can be stored frozen for months and years. Therefore no running cell culture lab is required.
The key to SSM-based electrophysiology is the exchange of solutions to provide the substrate or ligand and activate the transporter. The following charge translocation is detected and can be analyzed. Due to the high stability of the SSM up to one hundred sequential measurements can be performed on the same sample. This allows for determination of parameters such as EC50 or IC50. Since the time resolution of solution exchange is state-of-the-art, not only slow transport can be measured, but also fast binding reactions can be assayed and rate constants can be determined.
The device is easy-to-use and can be learned and mastered in only one day. It allows for automatic robotic measurements which reduces the involvement of the researcher tremendously. And it contains all equipment required for experiments in only one box, among this the liquid handling components, the electrophysiological hardware and even the computer.
For detailed information:
SURFE²R N1 Device and Software
The SURFE2R N1 device
The SURFE2R (surface electrogenic event reader) technology is the only available commercial solution for SSM-based electrophysiology on the market. Nanion Technologies developed the SURFE2R 96SE, a high-throughput system mainly used in pharmaceutical industry for drug screening purposes and the SURFE2R N1 designed for basic research.
The SURFE2R N1 device contains electrophysiological hardware, liquid handling components and the computer running Windows, plus the data recording and analysis software SurfControl. It’s an easy-to-learn, all-in-one robotic workstation which can measure 150 data points a day in a fully automated manner.
The SURFE2R N1 works with reusable sensor chips on which the membranes containing the protein of interest are adsorbed. The measurement is initiated by a substrate concentration jump. The solution exchange is controlled by the Ionjet, a robot-controlled pipette which loads solution from storage containers and injects them to the sensor enclosed by a Faraday cage. The Ionjet allows the measurement of fast kinetics with low solution consumption. An autosampler on top of the device allows placing up to 53 solutions for automated sequential measurements. During the measurement, the transport current can be viewed, compared and analyzed within the SurfControl software. The main characteristics of the device include a low-noise amplifier and a large sensor surface which both ensure a superior signal to noise ratio.
SURFE2R N1 Control Software and Automatization
The device comes with the SURFE2R N1 Control software pre-installed on the internal computer. This forms both the recording and analysis software. The functions of SurfControl include the managing and coding of workflows which represent protocols for SURFE2R assays. Workflows can contain multiple measurements, e.g. using different substrate concentrations or the comparison of transport before and after inhibition. The workflow includes parameters like duration, speed and volume of solution flow during the experiment, the number and sequence of different buffers, the number of repetitions per measurement, the incubation times between experiments and the volume used for rinsing the sensor after an experiment. During the run of one workflow no interference by the researcher is required.
Beside the design of the experiment itself, SurfControl enables the researcher to view and compare recorded traces. The graphical window allows peak detection and the calculation of the peak integrals including baseline subtraction. An additional results window is used for automated documentation of the traces including file name, values for peaks and integrals and the time of measurement. For further analysis, e.g. the fitting of kinetic parameters or the subtraction of negative control currents, the software is capable of exporting the data to the standard file format ASCII.
Consumables
SURFE²R N1 Single Sensor Chips
The SURFE²R N1 sensor chip is a proprietary innovative product by Nanion Technologies, developed for the SURFE²R N1. It is produced by an external partner, quality-assured in-house at Nanion headquarters and shipped from Munich to our international customers.
Material
The core structure of SURFE²R N1 sensor chip is a gold-coated sensor with 3 mm diameter. This structure is incorporated into a screw cap for easy handling. The SURFE²R N1 single sensor chips can be reused after an appropriate cleaning protocol.Available chip type
- "SURFE²R N1 Single Sensor Chip" (Order # 161001)
Validated Targets: SSM-based Electrophysiology
Testimonials & Case Studies
Dr. Arnaud Javelle - Statement about the SURFE²R N1 Device
“Using the SURFE2R N1 we have recently obtained high quality data in a very short period of time. We have developed an assay to measure the activity of ammonium transporters from the Amt protein family. There has been considerable controversy over the mechanism of ammonium transport by Amt proteins and the controversy was due to the lack of quantitative kinetic data characterizing the activity of the proteins at the single channel level. The SSM technologies allows to overcome this hurdle and we are now capable of answering very challenging functional questions concerning the mechanisms and the energetics of these transporters."
Dr. Arnaud Javelle, Chancellor's fellow, Strathclyde Institute of Pharmacy and Biomedical Sciences
Dr. Thomas Seeger & Karin V. Niessen - Statement about the SURFE²R Technology
“The SURFE²R makes extremely challenging electrophysiological targets accessible to robust routine analyses. For example, we have developed an assay for investigating nicotinic acetylcholine receptor ion channels, using membranes from the Pacific electric ray, Torpedo California. In this way, we overcome many of the well-known difficulties associated with this ion channel, which allows us to efficiently obtain information regarding compound pharmacology. Obtained pharmacology values match those of patch clamp recordings exceptionally well. We find that the SURFE²R is an excellent platform for characterization of electrogenic processes in isolated membranes.”
Karin V. Niessen, Dr. Thomas Seeger
Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
Nathan Thomas - Statement about the SURFE²R N1 Device
“We started collaborating with Nanion after receiving the Nanion´s SURFE²R N1 grant in 2018. The SURFE²R N1 has generated terrific functional data from the very first day it was installed in our lab. In general, it's very reliable and easy to use. Also, whenever we have run into issues or had questions about results, Nanion has provided prompt and helpful support”
Nathan Thomas
5th Year PhD student at University of Wisconsin-Madison, USA (Dr. Henzler-Wildman's lab)
Prof. Dr. Klaus Fendler - Statement about the SURFE²R N1 Device
“SSM-based electrophysiology is a well-established technique developed in our lab in the early 1990s for the investigation of electrogenic membrane transporters. It works with a wide range of samples from mammalian cell membranes over microbial membrane vesicles to proteoliposomes. SSM-based electrophysiology is especially useful in cases where conventional electrophysiology cannot be applied, e.g. for transporters residing in intracellular membranes or plasma membranes of small microbial cells. The SURFE2R N1 is a commercial instrument for SSM based electrophysiology which facilitates basic research in the field of membrane transport.“
Prof. Dr. Klaus Fendler
Max-Planck Institute of Biophysics, Frankfurt, Germany
Prof. Dr. Klaus Fendler and Co-Authors - Interview about the SURFE²R Technology
““SSM-based electrophysiology is a suitable technique to study bacterial ion-translocating membrane- systems which are otherwise difficult to approach using conventional electrophysiological techniques, like patch clamp.
Additionally, the mechanical stability of SSMs facilitates the transport activation through fast solution exchange, a condition that is technically challenging in a setup of a bilayer separating two solution-containing compartments.“
Dr. Miyer Fabián Patiño-Ruiz,
Faculty of Science and Engineering, University of Groningen, the Netherlands
Dr. Andre Bazzone, Application Scientist for the SURFE²R product family interviewed the authors of the publication:
"Mutation of two key aspartate residues alters stoichiometry of the NhaB Na+/H+ exchanger from Klebsiella pneumoniae"
Published 2019 in Nature Scientific Reports.
Read the publication here and download the full case study here:
SURFE²R Technology Customer Case Study (2020) 
(1.3 MB)
Nature Scientific Reports: Characterization of the Na+/H+ exchanger NhaB on the SURFE²R N1
Prof. Dr. Randy Stockbridge - Interview about the SURFE²R Technology
“We wanted to characterize the electrophysiological characteristics of our new family of transporters to find out properties such as Km and Vmax of the substrate, and ideally to screen a set of substrates for transporter activity. However, given our difficulties in developing a transport assay, I was pessimistic that we were going to be able to move beyond radiolabeled substrates.
Contrary to my expectations, electrophysiology with the SURFE²R N1 platform worked right away. We saw very robust currents in our pilot experiments during the initial training session on the instrument.“
Prof. Dr. Randy Stockbridge, Assistant Professor
University of Michigan, USA
Download the full case study here:
SURFE²R Technology Customer Case Study (2019) (1.8 MB)
Replacing Radiolabeling Techniques with the SURFE²R N1
Data and Applications
Adenine Nucleotide Translocator (ANT) - Recorded on the Surfer
SURFE2R N1 data and applications:
The Adenine Nucleotide Translocator (ANT) is located in the inner membrane of mitochondria and transports, as the name suggests, either ADP or ATP alone or against each other. Recordings were done on mitochondria inner membrane preparations from pigs heart. Example traces display the action of ANT either in the presence of ATP, in an other experiment in the presence of ADP.
AmtB - Activation by ammonium
SURFE2R N1 data and applications:
Purified AmtB from E.Coli was incorporated into liposomes and used on the SURFE2R N1. Shown are transient currents measured after a 100 mM ammonium jump in empty liposomes (green) or proteoliposomes containing AmtB at a lipid protein ratio (LPR) of 50 (black), 10 (red) or 5 (blue). Insert: Normalized current measured in proteoliposomes containing AmtB at an LPR of 50 (black), 10 (red) or 5 (blue).
Data from Mirandela et al, 2018
AmtB - Substrate specificity
SURFE2R N1 data and applications:
Purified AmtB from E.Coli was incorporated into liposomes and used on the SURFE2R N1. AmtB substrate specificity. (A) Transient current measured after a 100 mM substrate jump. Ammonium (red), methylammonium (black), potassium (green) or sodium (purple). Potassium and sodium do not act as substrates for AmtB and methylammonium translocates but at a much reduced rate compared with ammonium. Insert: Normalised current after a 100 mM substrate jump. Ammonium (red), methylammonium (black).
Data from Mirandela et al, 2018
ATP7B - Kinetics of different ATPases
SURFE2R N1 data and applications:
We compared the kinetics of the transient currents observed for three different ATPases: The current traces of the Cu2+ ATPases ATP7B and LpCopA show only slow decay times, while the current trace for SERCA decays much faster.
Data from Tadini-Buoninsegni et al, 2017
ATP7B - pH dependence
SURFE2R N1 data and applications:
We compared the pH dependence of the human Cu2+ ATPase ATP7B with the Ca2+ ATPase SERCA. X2+/H+ exchange is a specific feature of SERCA, which is not observed in ATP7B.
Data from Tadini-Buoninsegni et al, 2010
ATP8A2 (Flippase) - Inhibition with vanadate and negative control
SURFE2R N1 data and applications:
We measured ATP8A2 mediated and ATP-dependent flips of phosphatidylserine. When the ATPase activity is inhibited or when liposomes without ATP8A2 are used, no charge translocation is measured.
Clc - EC50 for inward and outward directed chloride flux
SURFE2R N1 data and applications:
We determined EC50 and relative Vmax for Cl- in an Cl-/H+ exchange assay for both transport directions and found a slight asymmetry in transporter kinetics.
Clc - Inhibition with OADS
SURFE2R N1 data and applications:
We investigated the effect of the specific Clc inhibitor OADS on the transport activity of Clc and its reversibility.
Clc - Inward and outward directed chloride flux
SURFE2R N1 data and applications:
According to the transport direction of 2Cl-/1H+ exchange, we observed positive (Cl- efflux) or negative (Cl- influx) transient currents.
Clc - Proteoliposomes with different lipid-to-protein ratios
SURFE2R N1 data and applications:
We tested proteoliposomes with different densities of reconstituted Clc protein for their signal-to-noise ratios and compared the obtained signal amplitudes with a negative control: liposomes without reconstituted protein.
EAAT3 - Current Traces at different Sodium Chloride Concentrations
SURFE2R N1 data and applications:
EAAT3 current traces were recorded after application of different Sodium Chloride concentrations. The EC50 of the peak current was determined as 42.2 mM.
Kdp - EC50 for ATP of wt and a transport-deficient mutant
SURFE2R N1 data and applications:
We compared ATP-induced K+ translocation in WT Kdp and a transport deficient mutant and determined the EC50 for ATP.
NCX_Mj - EC50 for Calcium and Magnesium
SURFE2R N1 data and applications:
Measurement of the transport activity of NCX_Mj. The first solution exchange provides a Na+-free solution to establish an outward directed Na+ gradient; the second solution exchange provides the divalent cation to activate the ion exchanger. By applying different concentrations of one divalent cation on the same sensor, we determined EC50 for Ca2+, Mg2+ and Sr2+.
NCX1 - Block by KB-R7943
SURFE2R N1 data and applications:
Cardiac NCX1 expressed in iCell® Cardiomyocytes2, Cor.4U® Cardiomyocytes or HEK cells was blocked by increasing concentrations of KB-R7943.
NCX1 - Block by SEA0400
SURFE2R N1 data and applications:
Cardiac NCX1 expressed in iCell® Cardiomyocytes2 or HEK cells was blocked by increasing concentrations of SEA0400, a specific blocker of NCX.
NCX1 - Current traces recorded from Cor.4U Cardiomyocytes, iCell Cardiomyocytes and HEK cells
SURFE2R N1 data and applications:
Cardiac NCX1 was activated using 30 μM Ca2+ on the SURFE2R N1. NCX1 was recorded from Cor.4U® Cardiomyocytes, iCell® Cardiomyocytes2 or overexpressed in HEK cells. The calcium affinity was determined for NCX1 recorded from iCell® Cardiomyocytes2 and HEK cells, shown on the right.
Organic Cation Transporter 2 (OCT2) - Pharmacology
SURFE2R N1 data and applications:
EC50 values and relative Vmax for three different substrates are shown.
The IC50 value for Choline was determined as 4.6 mM, for TEA as 0.33 mM and for Metformin as 8.6 mM.
PepT1 - Pharmacology of Lys[Z(NO2)]-Val
SURFE2R N1 data and applications:
Representive traces of PepT1 overexpressed in CHO cells. PepT1 (SLC15A1) is expressed mainly in intestine and kidney, it enables uptake of oligopeptides. The PepT1 signal is evoked by glycylglycin. The transport of oligopeptides can be inhibited by addition of Lys[Z(NO2)]-Val. The IC50 of Lys[Z(NO2)]-Val was 380µM.
Respiratory Chain Complex I and III - Current Over Mitochondrial Membrane
SURFE2R N1 data and applications:
In the respiratory chain Complex I and III, oxidation of NADH leads to transport of 4 protons across the membrane. The electrons are transferred to cytochrome c. Because of the electron leakage to oxygen, both complex are the main sites of production of harmful superoxide. In these experiments using the SURFE2R N1, application of 100µM NADH results in a current over the mitochondrial membrane, where Complex I and III are expressed.
Respiratory Chain Complex II and III - Current Traces
SURFE2R N1 data and applications:
Respiratory Chain Complex II is a succinate dehydrogenase. In this complex, succinate is oxidated to fumarate. The electrons are transfered to the quinone pool, the Complex III (cytochrome bc1 complex) and cytochrome c, while four protons are transported to the intermembrane space.
Respiratory Chain Complex IV - Current Traces
SURFE2R N1 data and applications:
The Respiratory Chain Complex IV, known as Cytochrom c oxidase, reduces oxygen by cunsumption of electrons from cytocrome c and transport of two protons to the intermembrans space. Here the reaction runs backwards.
Respiratory Chain Complex V - Action of the ATP Synthase after Application of ATP
SURFE2R N1 data and applications:
The Respiratory Chain Complex V uses the transmembrane proton gradient (produced by Complex I, III and IV) to generates ATP from ADP plus phosphate. One component of ATP synthase acts as an ion channel that provides for a proton flux back into the mitochondrial matrix. This reflux releases free energy, which is used to drive ATP synthesis, catalyzed by the other component of the complex. Experiments on the SURFE2R N1 show the action of the ATPase after application of ATP.
SERCA - IC50 for Cisplatin
SURFE2R N1 data and applications:
Ca2+-transport in SERCA is triggered by ATP hydrolysis. Using ATP concentration jumps, the authors determined the IC50 of SERCA inhibition by cisplatin
SGLT1 - Current Traces after Application of alpha-MDG
SURFE2R N1 data and applications:
Current traces after application of 10 mM and 50 mM alpha-MDG.
Sodium-Potassium ATPase - Analysis
SURFE2R N1 data and applications:
The Sodium-Potassium ATPase, also known as Na+/K+ pump is responsible for the active transport of Na+ and K+ in the cells containing relatively high concentrations of K+ ions but low concentrations of Na+ ions. The Na+/K+-ATPase helps maintain resting potential, avail transport, and regulate cellular volume. Here, we demonstrate the conductance of the pump, in the presence of ATP, Na+ and K+, or in the presence of ATP and Na+.
Webinars and Movies
2020 - SURFE²R N1 Product Video
SURFE²R N1 product video
Label free, real time measurements - electrophysiological approach. Record the action of billion transporters simultaneously.
2018 - Transporters Investigated Using the SURFE²R Instruments
SURFE²R 96SE and SURFE²R N1 Oral Presentation
Presenter:
Dr. Maria Barthmes, Product Manager SURFE²R product family, Nanion Technologies GmbH, Germany
2018 - Electrophysiological Characterization of Sugar Transporters using SSM-based Electrophysiology
SURFE²R 96SE and SURFE²R N1 Oral Presentation
Presenter:
Dr. Andre Bazzone, Application Scientist, Nanion Technologies GmbH, Germany
Andre is an expert in the field of SSM-based electrophysiology: He made his PhD at the Max-Planck-Institute of Biophysics in Frankfurt, Germany on the electrophysiological characterization of sugar transporters using the SSM-based electrophysiology in 2016. Right afterwards, he started as Application Scientist at Nanion Technologies and today he is an important member of the Nanion SURFE²R team.
2017 - Variations on the Coupling Theme in Secondary Active Transport
SURFE²R N1 Oral Presentation
Presenter:
Gregor Madej, University of Regensburg, Germany
Downloads:
Application Notes
CNT1 - "Electrophysiological recordings of CNT1 (SLC28A1) activity on Nanion’s SURFE²R N1"
SURFE2R N1 application note (0.4 MB)
EAAT3 - "Electrophysiological recordings of EAAT3 (SLC1A1) activity on Nanion’s SURFE²R N1"
SURFE²R application note (0.4 MB)
GAT1 - "Electrophysiological recordings of hGAT1 (SLC6A1) activity on Nanion’s SURFE²R N1"
SURFE²R application note (0.4 MB)
Neurons - "Electrophysiological recordings of LGIC and AA transporters in iCell® GlutaNeurons"
Patchliner, 
SyncroPatch 384PE (a predecessor model of the SyncroPatch 384i) and SURFE2R N1 application note: (0.5 MB)
Cells were kindly provided by FUJIFILM Cellular Dynamics, Inc.
PepT1 - "Electrophysiological recordings of PepT1 (SLC15A1) activity on Nanion’s SURFE²R"
SURFE²R N1 application note: (0.9 MB)
Product Sheets
Quickstart Guides
SURFE²R N1 - Quickstart Guide "Protocols"
SURFE²R N1 Quickstart Guide "Protocols"
Publications
2020 - Unlocking the Reversal Potential of Solid Supported Membrane Electrophysiology to Determine Transport Stoichiometry
SURFE²R N1 pre-publication in bioRxiv (2020)
Authors:
Henzler-Wildman K.A., Thomas N.E.
2020 - Protein Adsorption on Solid Supported Membranes: Monitoring the Transport Activity of P-Type ATPases
SURFE²R 96SE and SURFE²R N1 Review in Molecules (2020)
Authors:
Tadini-Buoninsegni F.
2020 - Label-Free Bioelectrochemical Methods for Evaluation of Anticancer Drug Effects at a Molecular Level
SURFE²R 96SE and SURFE²R N1 Review article in Frontiers in Sensors (2020)
Authors:
Tadini-Buoninsegni F.,Palchetti I.
2020 - Energy Coupling in Cation-Pumping Pyrophosphatase - Back to Mitchell
SURFE²R N1 publication in Frontiers in Plant Science (2020)
Authors:
Baykov A.A.
2020 - Electrophysiology Measurements of Metal Transport by MntH2 from Enterococcus faecalis
SURFE2R N1 publication in Membranes (2020)
Authors:
Gantner M., Laftsoglou T., Rong H., Postis V.L.G., Jueken L.J.C.
2019 - Phosphatidylserine flipping by the P4-ATPase ATP8A2 is electrogenic
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in PNAS (2019)
Authors:
Tadini-Buoninsegni F., Mikkelsen S.A., Mogensen L.S., Molday R.S., and Andersen J.P.
2019 - Mutation of two key aspartate residues alters stoichiometry of the NhaB Na+/H+ exchanger from Klebsiella pneumoniae
SURFE²R N1 publication in Nature Scientific Reports (2019)
Authors:
Patiño-Ruiz M., Fendler K., & Călinescu O.
2019 - Functional Reconstitution of Membrane Proteins Derived From Eukaryotic Cell-Free Systems
SURFE2R N1 and 
Orbit 16 publication in Frontiers in Pharmacology (2019)
Authors:
Dondapati S.K., Lübberding H., Zemella A., Thoring L., Wüstenhagen D.A., Kubick S.
2019 - A two-lane mechanism for selective biological ammonium transport
SURFE²R N1 pre-publication in bioRxiv (2019)
Authors:
Williamson G., Tamburrino G., Mirandela G.D., Boeckstaens M., Bage M., Pisliakov A., Ives C.M., Terras E.T., Bizior A., Hoskisson P.A., Marini A.M., Zachariae U., Javelle A.
2018 - The lipid environment determines the activity of the E. coli ammonium transporter, AmtB
SURFE²R N1 publication in Faseb J (2018)
Authors:
Mirandela G.D., Tamburrino G., Hoskisson P.A., Zachariae U., Javelle A.
2017 - SSM-Based Electrophysiology for Transporter Research
SURFE²R N1 and SURFE²R 96SE book chapter in Methody in Enzymology
Authors:
Bazzone A., Barthmes M., Fendler K.
2017 - Mechanisms of charge transfer in human copper ATPases ATP7A and ATP7B
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in IUBMB Life (2017)
Authors:
Tadini-Buoninsegni F., Smeazzetto S.
2017 - Insights into the mechanism of membrane pyrophosphatases by combining experiment and computer simulation
SURFE²R N1 publication in Structural Dynamics (2017)
Authors:
Shah N.R., Wilkinson C., Harborne S.P.D., Turku A., Li K.-M., Sun Y.-J., Harris S., Goldman A.
2017 - Effect of cisplatin on the transport activity of PII-type ATPases
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Metallomics (2017)
Authors:
Tadini-Buoninsegni F., Sordi G, Smeazzetto S, Natile G, Arnesano F.
2017 - Discovery of Compounds that Positively Modulate the High Affinity Choline Transporter
SURFE²R N1 publication in Frontiers in Molecular Neuroscience (2017)
Authors:
Choudhary P., Armstrong E.J., Jorgensen C.C., Piotrowski M., Barthmes M., Torella R., Johnston S.E., Maruyama Y., Janiszewski J.S., Storer R.I., Skerratt S.E., Benn C.L.
2017 - Conformational memory in the association of the transmembrane protein phospholamban with the sarcoplasmic reticulum calcium pump SERCA
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Journal of Biological Chemistry (2017)
Authors:
Smeazzetto S., Armanious G.P., Moncelli M.R., Bak J.J., Lemieux M.J., Young H.S., Tadini-Buoninsegni F.
2017 - Competition is the basis of the transport mechanism of the NhaB Na+/H+ exchanger from Klebsiella pneumoniae
SURFE²R-technology (custom-built system) publication in PLoS ONE (2017)
Authors:
Patiño-Ruiz M., Ganea C., Fendler K., Călinescu O.
2016 - pH Regulation of Electrogenic Sugar/H+ Symport in MFS Sugar Permeases
SURFE²R-technology (custom-built system) publication in PLoS ONE (2016)
Authors:
Bazzone A., Madej M.G., Kaback H.R., Fendler K.
2016 - Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism
SURFE²R N1 publication in Nature Communications (2016)
Authors:
Li K., Wilkinson C., Kellosalo J., Tsai J., Kajander T, Jeuken L.J.C., Sun Y., Goldman A.
2016 - Functional characterization of solute carrier (SLC) 26/sulfate permease (SulP) proteins in membrane mimetic systems
SURFE²R-technology (custom-built system) publication in Biochimica et Biophysica Acta (BBA) - Biomembranes (2016)
Authors:
Srinivasan L., Baars T.L., Fendler K., Michel H.
2016 - Electrophysiological characterization of the archaeal transporter NCX_Mj using solid supported membrane technology
SURFE²R N1 and 
Vesicle Prep Pro publication in Journal of General Physiology (2016)
Authors:
Barthmes M., Liao J., Jiang Y., Brüggemann A., Wahl-Schott C.
2016 - Electrogenic Cation Binding in the Electroneutral Na+/H+ Antiporter of Pyrococcus abyssi
SURFE²R-technology (custom-built system) publication in Journal of Biological Chemistry (2016)
Authors:
Călinescu O., Linder M., Wöhlert D., Yildiz Ö., Kühlbrandt W., Fendler K.
2016 - Charge translocation by mitochondrial NADH:ubiquinone oxidoreductase (complex I) from Yarrowia lipolytica measured on solid-supported membranes
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Biochemical and Biophysical Research Communications (2016)
Authors:
Siebels I., Dröse S.
2015 - Structural and Functional Studies of NirC from Salmonella typhimurium
SURFE²R-technology (custom-built system) publication in Methods in Enzymology (2015)
Authors:
Rycovska-Blume A., Lü W., Andrade S., Fendler K., Einsle O.
2015 - Hofmeister effect of anions on calcium translocation by sarcoplasmic reticulum Ca2+-ATPase
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Nature Scientific Reports (2015)
Authors:
Tadini-Buoninsegni F., Moncelli M.R., Peruzzi N., Ninham B.W., Dei L., Lo Nostroa P.
2015 - A universal mechanism for transport and regulation of CPA sodium proton exchangers
SURFE²R-technology (custom-built system) publication in Biological Chemistry (2015)
Authors:
Călinescu O., Fendler K.
2015 - A sulfur‐based transport pathway in Cu+‐ATPases
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in EMBO Reports (2015)
Authors:
Mattle D., Zhang L., Sitsel O., Pedersen L.T., Moncelli M.R., Tadini-Buoninsegni F., Gourdon P., Rees D.C., Nissen P., Meloni G.
2014 - Substrate-bound outward-open state of the betaine transporter BetP provides insights into Na+ coupling
SURFE²R-technology (custom-built system) publication in Nature Communications (2014)
Authors:
Perez C., Faust B., Mehdipour A.R., Francesconi K.A., Forrest L.R., Ziegler C.
2014 - Species differences in bacterial NhaA Na+/H+ exchangers
SURFE²R-technology (custom-built system) publication in FEBS Letters (2014)
Authors:
Călinescu O., Danner E., Böhm M., Hunte C., Fendler K..
2014 - NhaA Na+/H+ antiporter mutants that hardly react to the membrane potential
SURFE²R-technology (custom-built system) publication in PLoS ONE (2014)
Authors:
Alkoby D., Rimon A., Budak M., Patino-Ruiz M., Călinescu O., Fendler K., Padan E..
2014 - Molecular characterization of the Na+/H+-antiporter NhaA from Salmonella Typhimurium
SURFE²R-technology (custom-built system) publication in PLoS ONE (2014)
Authors:
Lentes C.J., Mir S.H., Boehm M., Ganea C., Fendler K., Hunte C.
2014 - Keeping it simple, transport mechanism and pH regulation in Na+/H+ exchangers
SURFE²R-technology (custom-built system) publication in Journal of Biological Chemistry (2014)
Authors:
Călinescu O., Paulino C., Kühlbrandt W., Fendler K.
2014 - Industrializing Electrophysiology: HT Automated Patch Clamp on SyncroPatch 96 Using Instant Frozen Cells
SURFE²R N96 (predecessor model of SURFE²R 96SE) book chapter in Patch-Clamp Methods and Protocols
Authors:
Polonchuk L.
2014 - Direct observation of electrogenic NH4(+) transport in ammonium transport (Amt) proteins
SURFE²R-technology (custom-built system) publication in PNAS (2014)
Authors:
Wacker T., Garcia-Celma J.J., Lewe P., Andrade S.L.
2014 - Anticancer Ruthenium(III) Complex KP1019 Interferes with ATP-Dependent Ca2+ Translocation by Sarco-Endoplasmic Reticulum Ca2+-ATPase (SERCA)
SURFE²R N1 publication in ChemMedChem (2014)
Authors:
Sadafi F.Z., Massai L., Bartolommei G., Moncelli M.R., Messori L., Tadini-Buoninsegni F.
2013 - Photocycle and vectorial proton transfer in a rhodopsin from the eukaryote Oxyrrhis marina
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Biochemistry (2013)
Authors:
Janke C., Scholz F., Becker-Baldus J., Glaubitz C., Wood P.G., Bamberg E., Wachtveitl J., Bamann C.
2013 - Functional characterization of a ClC transporter by solid-supported membrane electrophysiology
SURFE²R-technology (custom-built system) publication in Journal of General Physiology (2013)
Authors:
Garcia-Celma J., Szydelko A., Dutzler R.
2013 - Enhanced adsorption of Ca-ATPase containing vesicles on a negatively charged solid supported membrane for the investigation of membrane transporters
SURFE²R N1 publication in Langmuir (2013)
Authors:
Sacconi A., Moncelli M.R., Mergheri G., Tadini-Buoninsegni F.
2013 - Electrophysiological characterization of uncoupled mutants of LacY
SURFE²R-technology (custom-built system) publication in Biochemistry (2013)
Authors:
Gaiko O., Bazzone A., Fendler K., Kaback H.R.
2013 - Differential Effects of Mutations on the Transport Properties of the Na+/H+ Antiporter NhaA from Escherichia coli
SURFE²R-technology (custom-built system) publication in Journal of Biological Chemistry (2013)
Authors:
Mager T., Braner M., Kubsch B., Hatahet L., Alkoby D., Rimon A., Padan E., Fendler K.
2012 - The nitrite transport protein NirC from Salmonella typhimurium is a nitrite/proton antiporter
SURFE²R-technology (custom-built system) publication in Biochimica et Biophysica Acta (BBA) - Biomembranes (2012)
Authors:
Rycovska A., Hatahet L., Fendler K., Michel H.
2012 - Investigation of the sodium-binding sites in the sodium-coupled betaine transporter BetP
SURFE²R-technology (custom-built system) publication in PNAS (2012)
Authors:
Khafizov K., Perez C., Koshy C., Quick M., Fendler K., Ziegler C., Forrest L.R.
2012 - Distinctive features of catalytic and transport mechanisms in mammalian sarco-endoplasmic reticulum Ca2+ ATPase (SERCA) and Cu+ (ATP7A/B) ATPases
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Journal of Biological Chemistry (2012)
Authors:
Lewis D., Pilankatta R., Inesi G., Bartolommei G., Moncelli M.R., Tadini-Buoninsegni F.
2012 - Assaying the proton transport and regulation of UCP1 using solid supported membranes
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in European Biophysics Journal (2012)
Authors:
Blesneac I., Ravaud S., Machillot P., Zoonens M., Masscheylen S., Miroux B., Vivaudou M., Pebay-Peyroula E.
2011 - Transport Mechanism and pH Regulation of the Na+/H+ Antiporter NhaA from Escherichia coli
SURFE²R-technology (custom-built system) publication in Journal of Biological Chemistry (2011)
Authors:
Mager T., Rimon A., Padan E., Fendler K.
2011 - Robust Electrophysiological Assays using Solid Supported Membranes: the Organic Cation Transporter OCT2
SURFE²R ONE (a predecessor model of the SURFE²R N1) publication in Australian Journal of Chemistry (2011)
Authors:
Gaiko O., Janausch I., Geibel S., Vollert H., Arndt P., Gonski S., Fendler K.
2011 - G117C MelB, a mutant melibiose permease with a changed conformational equilibrium
SURFE²R-technology (custom-built system) publication in Biochimica et Biophysica Acta (BBA) - Biomembranes (2011)
Authors:
Ganea C., Meyer-Lipp K., Lemonnier R., Krah A., Leblanc G., Fendler K.
2011 - Development of an assay for Complex I/Complex III of the respiratory chain using solid supported membranes and its application in mitochondrial toxicity screening in drug discovery
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in ASSAY and Drug Development Technologies (2011)
Authors:
Preissl S., Bick I., Obrdlik P., Diekert K., Gul S., Gribbon P.
2011 - Characterisation of the purified human sodium/iodide symporter reveals that the protein is mainly present in a dimeric form and permits the detailed study of a native C-terminal fragment
SURFE²R-technology (custom-built system) publication in Biochimica et Biophysica Acta (BBA) - Biomembranes (2011)
Authors:
Huc-Brandt S., Marcellin D., Graslin F., Averseng O., Bellanger L., Hivin P., Quemeneur E., Basquin C., Navarro V., Pourcher T., Darrouzet E.
2010 - The G215R Mutation in the Cl−/H+-Antiporter ClC-7 Found in ADO II Osteopetrosis Does Not Abolish Function but Causes a Severe Trafficking Defect
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in PLoS ONE (2010)
Authors:
Schulz P., Werner J., Stauber T., Henriksen K., Fendler K.
2010 - Solid-supported membrane technology for the investigation of the influenza A virus M2 channel activity
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Pflügers Archiv - European Journal of Physiology (2010)
Authors:
Balannik V., Obrdlik P., Inayat S., Steensen C., Wang J., Rausch J.M., DeGrado W.F., Kelety B., Pinto L.H.
2010 - Electrophysiology of respiratory chain complexes and the ADP-ATP exchanger in native mitochondrial membranes
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Biochemistry (2010)
Authors:
Watzke N., Diekert K., Obrdlik P.
2010 - Electrophysiological characterization of ATPases in native synaptic vesicles and synaptic plasma membranes
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Biochemical Journal (2010)
Authors:
Obrdlik P., Diekert K., Watzke N., Keipert C., Pehl U., Brosch C., Boehm N., Bick I., Ruitenberg M., Volknandt W., Kelety B.
2010 - Delineating electrogenic reactions during lactose/H+ symport
SURFE²R-technology (custom-built system) publication in Biochemistry (2010)
Authors:
Garcia-Celma J.J., Ploch J., Smirnova I., Kaback H.R., Fendler K.
2010 - ATP dependent charge movement in ATP7B Cu+-ATPase is demonstrated by pre-steady state electrical measurements
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in FEBS Letters (2010)
Authors:
Tadini-Buoninsegni F., Bartolommei G., Moncelli M.R., Pilankatta R., Lewis D., Inesi G.
2009 - Measuring Ion Channels on Solid Supported Membranes
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Biophysical Journal (2009)
Authors:
Schulz P., Dueck B., Mourot A., Hatahet L., Fendler K.
2009 - Inhibitory effect of Pb2+ on the transport cycle of the Na+,K+-ATPase
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Chemical Research in Toxicology (2009)
Authors:
Gramigni E., Tadini-Buoninsegni F., Bartolommei G., Santini G., Chelazzi G., Moncelli M.R.
2009 - Electrophysiological characterization of LacY
SURFE²R-technology (custom-built system) publication in PNAS (2009)
Authors:
Garcia-Celma J.J., Smirnova I.N., Kaback H.R., Fendler K.
2009 - Electrogenic ion pumps investigated on a solid supported membrane: comparison of current and voltage measurements
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Langmuir (2009)
Authors:
Bartolommei G., Moncelli M.R., Rispoli G., Kelety B., Tadini-Buoninsegni F.
2009 - DtpB (YhiP) and DtpA (TppB, YdgR) are prototypical proton-dependent peptide transporters of Escherichia coli
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in The FEBS Journal (2009)
Authors:
Harder D., Stolz J., Casagrande F., Obrdlik P., Weitz D., Fotiadis D., Daniel H.
2009 - An automatic electrophysiological assay for the neuronal glutamate transporter mEAAC1
SURFE²R-technology (custom-built system) publication in Journal of Neuroscience Methods (2009)
Authors:
Krause R., Watzke N., Kelety B., Dörner W., Fendler K.
2008 - Rapid activation of the melibiose permease MelB immobilized on a solid-supported membrane
SURFE²R-technology (custom-built system) publication in Langmuir (2008)
Authors:
Garcia-Celma J.J., Dueck B., Stein M., Schlueter M., Meyer-Lipp K., Leblanc G., Fendler K.
2008 - Identification of the arginine/ornithine antiporter ArcD from Halobacterium salinarum
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in FEBS Letters (2008)
Authors:
Wimmer F., Oberwinkler T., Bisle B., Tittor J., Oesterhelt D.
2008 - Effect of Clotrimazole on the Pump Cycle of the Na,K-ATPase
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Biophysical Journal (2008)
Authors:
Bartolommei G., Devaux N., Tadini-Buoninsegni F., Moncelli M., Apell H.-J.
2007 - Functional and structural characterization of a prokaryotic peptide transporter with features similar to mammalian PEPT1
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Journal of Biological Chemistry (2007)
Authors:
Weitz D., Harder D., Casagrande F., Fotiadis D., Obrdlik P., Kelety B., Daniel H.
2006 - Transporter assays using solid supported membranes: a novel screening platform for drug discovery
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in ASSAY and Drug Development Technologies (2006)
Authors:
Kelety B., Diekert K., Tobien J., Watzke N., Dörner W., Obrdlik P., Fendler K.
2006 - The inner interhelix loop 4-5 of the melibiose permease from Escherichia coli takes part in conformational changes after sugar binding
SURFE²R-technology (custom-built system) publication in Journal of Biological Chemistry (2006)
Authors:
Meyer-Lipp K., Séry N., Ganea C., Basquin C., Fendler K., Leblanc G.
2006 - Structure and function of prokaryotic glutamate transporters from Escherichia coli and Pyrococcus horikoshii
SURFE²R-technology (custom-built system) publication in Biochemistry (2006)
Authors:
Raunser S., Appel M., Ganea C., Geldmacher-Kaufer U., Fendler K., Kühlbrandt W.
2006 - Establishment of Cell-Free Electrophysiology for Ion Transporters: Application for Pharmacological Profiling
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Journal of Biomolecular Screening (2006)
Authors:
Geibel S., Flores-Herr N., Licher T., Vollert H.
2005 - Kinetics of charge translocation in the passive downhill uptake mode of the Na+/H+ antiporter NhaA of Escherichia coli
SURFE²R 500 (a predecessor model of SURFE²R N1) publication in Biochimica et Biophysica Acta (BBA) - Bioenergetics (2005)
Authors:
Zuber D., Krause R., Venturi M., Padan E., Bamberg E., Fendler K.
2004 - Time-resolved charge translocation by sarcoplasmic reticulum Ca-ATPase measured on a solid supported membrane
SURFE²R-technology (custom-built system) publication in Biophysical Journal (2004)
Authors:
Tadini Buoninsegni F., Bartolommei G., Moncelli M.R., Inesi G., Guidelli R.
2004 - Charge translocation during cosubstrate binding in the Na+/proline transporter of E.coli
SURFE²R-technology (custom-built system) publication in Journal of Molecular Biology (2004)
Authors:
Zhou A., Wozniak A., Meyer-Lipp K., Nietschke M., Jung H., Fendler K.
2004 - Calcium transport by sarcoplasmic reticulum Ca-ATPase can be investigated on a solid-supported membrane
SURFE²R-technology (custom-built system) publication in Bioelectrochemistry (2004)
Authors:
Bartolommei G., Buoninsegni F.T., Moncelli M.R.
2003 - Charge displacements during ATP-hydrolysis and synthesis of the Na+-transporting FoF1-ATPase of Ilyobacter tartaricus
SURFE²R-technology (custom-built system) publication in Biophysical Journal (2003)
Authors:
Burzik C., Kaim G., Dimroth P., Bamberg E., Fendler K.
2002 - Photocurrents Generated by Bacteriorhodopsin Adsorbed on Thiol/Lipid Bilayers Supported by Mercury
SURFE²R-technology (custom-built system) publication in Langmuir (2002)
Authors:
Dolfi A., Tadini-Buoninsegni F., Moncelli M.R., Guidelli R.
2001 - Evidence for intraprotein charge transfer during the transport activity of the melibiose permease from Escherichia coli
SURFE²R-technology (custom-built system) publication in Biochemistry (2001)
Authors:
Ganea C., Pourcher T., Leblanc G., Fendler K.
1999 - Kinetics of electrogenic transport by the ADP/ATP carrier
SURFE²R-technology (custom-built system) publication in Biophysical Journal (1999)
Authors:
Gropp T., Brustovetsky N., Klingenberg M., Müller V., Fendler K., Bamberg E.
1999 - Charge Translocation by the Na+/K+-ATPase Investigated on Solid Supported Membranes: Cytoplasmic Cation Binding and Release
SURFE²R-technology (custom-built system) publication in Biophysical Journal (1999)
Authors:
Pintschovius J., Fendler K., Bamberg E.
1999 - Charge Translocation by the Na/K-ATPase Investigated on Solid Supported Membranes: Rapid Solution Exchange with a New Technique
SURFE²R-technology (custom-built system) publication in Biophysical Journal (1999)
Authors:
Pintschovius J., Fendler K.
1993 - Charge transport by ion translocating membrane proteins on solid supported membranes
SURFE²R-technology (custom-built system) publication in Biophysical Journal (1993)
Authors:
Seifert K., Fendler K., Bamberg E.
Posters
2020 - A novel approach to detect electrogenic transporter activity in intact cells applied to investigate iPSC derived cardiomyocytes and neurons
SURFE²R N1 and 
SURFE²R 96SE poster, 64th Annual Meeting of the Biophysical Society (1.6 MB)
2020 - Drug effects on human Na+/Ca2+ exchanger and implications for testing new drug candidates
SURFE²R N1 and SURFE²R 96SE poster, Safety Pharmacology Society Virtual Meeting 2020 (1.2 MB)
2018 - Label-free analysis of Na+/Ca2+- exchanger (NCX) isolated from iPSC-derived cardiomyocytes
SURFE²R N1 and SURFE2R 96SE poster, Europhysiology Meeting 2018 (1.5 MB)
2018 - Transported by light: optogenetic control of NCX1
SURFE²R N1 poster, Biophysics Annual Meeting 2018 (2.2 MB)
2015 - Organellar Transporters and Ion Channels - How to access their electrophysiology by using the SURFE2R technology and Planar Patch Clamp
SURFE²R N1 and SyncroPatch 96 (a predecessor model of the SyncroPatch 384PE) and 
Port-a-Patch poster, GRC - Organellar Channels and Transporters 2015 (1.6 MB)
2017 - An emerging technique for the characterization of transport proteins: SSM-based electrophysiology
SURFE²R N1 and SURFE²R SE96 poster, 19th IUPAB / 11th EBSA congress 2017 (3.3 MB)
2015 - Functional Characterization of Prokaryotic NCX by Solid Supported Membrane Technology
SURFE²R N1 poster, Gordon Research Conference 2015 (0.9 MB)
Presentations
2020 - Unlocking the (Reversal) Potential of SSM Electrophysiology: Transporter Stoichiometry with the SURFE²R N1
SURFE²R N1 presentation (slide deck) (1.7 MB)
