When compared to traditional patch-clamp electrophysiology, the SURFE2R—surface electrogenic event reader—technology has been developed for the measurements of electrogenic transporters (exchangers, symporters, and uniporters) and pumps.

In general, these proteins exhibit low turnover rates than ion channels. The SURFE2R technology makes up for that with its large sensor size that facilitates the measurement of up to 109 transporters in parallel to produce the best signal-to-noise ratio.

The SURFE2R N1 has been engineered for standard research and universities. When there is a demand for higher throughput, the SURFE2R 96SE can measure 96 sensors in a completely parallel mode.

Key Features of the SURFE2R N1

  • Easy to learn, perfect for teaching
  • Automated recordings with nearly 52 different solutions
  • 150 data points per day
  • Multipurpose device, including electrophysiology hardware, liquid handling, and computer

Key Features of SSM-based Electrophysiology

  • Use purified membranes and vesicles from proteoliposomes or cells
  • More than 100 targets confirmed, 100 peer-reviewed papers using SSM-based electrophysiology
  • Label-free electrical measurements
  • Pumps, transporters, and ligand-gated channels
  • Capable of measuring even sugar-binding and electroneutral exchangers
  • Needs just 0.1–1 µg protein per sensor, which is enough for up to 100 experiments
  • High signal amplification compared to patch-clamp
  • Ability to resolve quick binding kinetics
  • Real-time data with high time resolution, not single-point read-out
  • IC50, EC50, rate constants, comparison of transporter variants, etc.

The technology involves using a solid-supported membrane (SSM)-based electrophysiology, which was developed in the late 1990s. The reusable sensors include a gold-coating on which the SSM is formed in a quick pipetting method. Subsequently, the sample with the preferred transporter is added on top such that it physically adsorbs to the SSM.

Any type of membrane preparation comprising the targeted protein can be employed for measurements, for example, proteoliposomes after the reconstitution of decontaminated proteins or membrane vesicles after cell disruption. These samples can be kept frozen for several months and even years, thus avoiding the need for a running cell culture lab.

The exchange of solutions is crucial in SSM-based electrophysiology to offer the ligand or substrate and stimulate the transporter. The resulting translocation of charge can be detected and investigated. Thanks to the high stability of the SSM, up to 100 sequential measurements can be carried out on the same sample.

This enables determining factors such as IC50 or EC50. The advanced time resolution of solution exchange enables not only the measurement of slow transport but also assaying of rapid binding reactions and establishing rate constants.

The device is user friendly and can be understood and mastered in a single day. It enables automatic robotic measurements, thereby considerably minimizing the involvement of the researcher. Furthermore, it contains all necessary equipment for experiments in just a single box, such as the electrophysiological hardware, the liquid handling components, and even the computer.