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:
Add-Ons and Features
The SURFE2R Stimulating Optical Lid (SOL)
The SURFE2R Stimulating Optical Lid (SOL) replaces our standard lid for the measurement chamber. The optical lid contains a plate with an integrated LED ring - exchangeable within seconds and available in eight different wavelengths. The LED may be used to activate light gated channels or light driven pumps such as Bacteriorhodopsin. But it can be also applied to generate a membrane voltage through the action of Channelrhodopsin or release caged compounds.
Usually the SURFE2R applies a solution exchange providing a substrate to activate the transporter and record the resulting transient transporter current. Now substrate and light activation can be used individually; or a combination of light and substrate stimuli enables experimental designs which were never seen before.
Besides the stimulating optical lid itself, the addon comes with new internal electronics and a powerful software upgrade to control the LEDs: We developed a new workflow editor which can be used to set several experimental parameters such as light intensity and to switch between continous and pulse modes.
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.
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.
MaterialThe 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
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