ECIS Cell Monitoring

ECIS is a new and important method of monitoring cell behaviour, particularly:

• Cell growth
• Cell attachment and spreading
• Cell motility and migration, for example after wounding
• Barrier function of confluent cell layers

ECIS - Electric Cell-Substrate Impedance Sensing

The ECIS core technology is based on a technique of measuring the change in impedance of a small electrode to AC current flow. The heart of the measurement is a specialized slide that has 8 individual wells for cell culturing. The base of the device has an array of gold film electrodes that connect the ECIS electronics to each of the 8 wells.

A 96-well format is also available, as well as specialised 8-well arrays (eg. for chemotaxis and flow studies).

ECIS results are typically a time-course of impedance, showing differecnes in cell behaviour in different wells (which in turn have different treatments of course).

This simple example shows 3 wells: one with BCS cells, one with NRK cells, and a control well with no cells. As the cells spread over the substrate, the impedance rises very significantly.The measurement is continuous and highly reproducible.

Another example is an automated would-healing assay, in which a confluent cell layer is wounded precisely over the area of the electrode (using the optional Elevated Field module), and cell migration into the wounded area is monitored using ECIS and without microscopy.

The ECIS 9600 is a high throughput, automated instrument designed to monitor cells grown in special arrays with a standard 96 well plate configuration and footprint. The consumable 96 well arrays (96W1E) are easily connected to the instrumentation using a single lever to make electrical contact. The instrument is capable of scanning all 96 wells in approximately 30 seconds.

All data acquisition and analysis is handled with user-friendly software running on Windows XP. Data can also be readily converted to text files for export to other data analysis systems.

The ECIS 9600 (6x16) has additional software and multiple array holders to allow alternative use with 6 independent pairs of 8-well arrays - ideal where there are multiple users.

The ECIS 1600 and ECIS 1600R instruments each have the capacity to monitor up to 16 individual tissue cultures, in a dual 8-well array format.

Two leads connect the electronics to an electrode array holder within the incubator space - this, in turn, makes contact with up to two consumable arrays. A USB cable provides communication to a PC that controls all data acquisition, storage and analysis. In addition to the ECIS electronics and software, the system is supplied with a state-of-the-art PC & monitor and an initial supply of electrode arrays. An optional compact CO2 tissue culture incubator is also available.

The ECIS 1600 measures the simple impedance of the well (in Ohms), whereas the ECIS 1600R measures complex impedance, which can be analysed into separate measures of the membrane resistance and capacitance components..

The ECIS 1600F and ECIS 800F instruments are designed specifically for researchers who wish to employ ECIS impedance measurements to study the behavior of cells under flow conditions. These instrument packages are turn-key systems with user-friendly software integrating ECIS measurements with flow control.

The standard ECIS flow arrays are used with the system providing eight independent measuring electrodes on the floor of a channel 0.5 cm wide and 5 cm long with a height of 400 micrometers. Flow can be programmed from slow rates to perfuse the cells with medium to high rates yielding shear stress similar to that experienced by endothelial cells in vivo. The flow programming also includes the ability to generate pulsed flows of different periods and with varying flow rates.

A peristaltic pump included with the system is designed for operation in the high humidity of the tissue culture incubator. All of the ECIS flow systems can be ordered with the optional elevated field module for electroporation studies or cell migration measurements via automated wound-healing assays.

The ECIS 800E has been designed specifically as an educational unit. This instrument is intended for hands-on, advanced undergraduate and graduate laboratory courses in tissue culture, cell biology, advanced biological methods or biotechnology. Students can be exposed to a variety of cell-based assays including measurements of in vitro toxicology, cell migration, cell-ECM interactions, extravasation of normal cell layers by cancer cells and signal transduction.

In addition to monitoring cells non-invasively, this instrument is equipped with the Elevated Field Module allowing the performance of automated wound-healing (cell migration) assays and experiments involving electroporation of membrane-impermeable compounds.

The electronics are consolidated in a single case that sits beside a tissue culture incubator. One lead connects the electronics to an electrode array holder within the incubator space - this, in turn, makes contact with a single consumable array. In addition to the ECIS electronics and software, the system is supplied with a state-of-the-art laptop PC, an initial supply of electrode arrays, as well as an ECIS workbook with 5 cell-based exercises for biology students to start learning cell impedance measurements.