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| Electrophoretic fingerprinting of cells and particles |
| Experimental fingerprints |
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| Measurements of the mean electrophoretic mobility of particles and cells in a wide range as a function of pH and the specific conductance of the electrolyte provide additional information about dissociation and adsorption processes onto particle/cell surfaces. The figure shows an experimental electrophoretic fingerprint of human red blood cells. |
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| Theoretical fingerprints |
| Based on a new method for particle and cell characterization which combines calculated and experimental electrophoretic fingerprints we are able to estimate a variety of surface determining characteristics of hairy surfaces such as thickness of the charged layer, depth of hydrodynamic flow, association constant of ions, surface conductivity, charge distribution, dissociation constants of surface chemical groups, and dielectric permittivity. This concept has been applied to the characterization of interactions between polymer surfaces and biological systems (biomaterial research), the dynamic behaviour of polyelectrolyte layers on surfaces, and particles used for biomedical diagnosis. The figures show the experimental fingerprint of silica particles (left side) compared to the theoretical fingerprint fitted to experimantal data (right side) Sigma (effective charge density, C/m2) vs. Kappa (inverse Debye-radius, 109m-1) and pH. |
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| Discrimination of experimental fingerprints |
| Discrimination of electrophoretic fingerprints of different surfaces enables the detection of very small differences in the membrane structure which can be used as a diagnostic tool. The figure demonstrates the difference in fingerprints of filtrated and non-filtrated human red blood cells after storage for 1 week (left side) and 5 weeks (right side). The difference of electrophoretic mobility ( EPM in 10-8m2/Vs) is plotted versus pH and the decadic logarithm of conductivity (in S/m). |
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