The 3DEP system
uses a patented chip design which is low cost, simple to use and allows the analysis of thousands of cells simultaneously.
Low cost disposable chips suitable for a large range of cell types from large myocytes to bacteria.
Applications include cancer diagnostics, monitoring apoptosis, stem-cell differentiation, drug discovery, in-vitro toxicology and many more.
- DEP is a phenomenon related to electrophoresis, but with some important differences.
- Electrophoresis, as its name suggests, measures the electric properties of a material – that is, its net charge. It uses a DC voltage to attract anions and cations to the relevant counterelectrode, and the speed and direction of movement can be used to determine the electrical properties.
- Dielectrophoresis is similar but uses a shaped AC field to determine the dielectric properties. These affect the particle’s dipole, and allow us to determine the dielectric properties (such as resistance and capacitance). We do this by observing particle motion at several AC frequencies, rather than at DC, and inferring the properties from analysing how the dipole changes at these different frequencies.
- Complex particles such as cells exhibit different behaviours at different frequencies. The measure of this is referred to as the DEP spectrum (plural: spectra) or, sometimes, the DEP fingerprint. From this, it is possible (either manually or automatically) to fit a best-fit curve and hence infer the properties of the particles from that best-fit model. There are four key parts to the curve: the starting level relates to the conductance of the membrane, the frequency where the curve goes up (called the lower dispersion) relates to the membrane capacitance, where it goes back down (the upper dispersion) shows the intracellular conductivity, and the final level at high frequencies gives the intracellular permittivity. Where data are quite noisy it may be useful to average several experimental spectra together to improve the fit.