A Breakthrough in Particle & Cell Electrophoresis
|Covers the entire scope of particle surface characteristics
Simultaneous measurement of mobility, size, sedimentation, shape, intensity ...
Multidimensional information for each measured particle
At least ten times more precise then Laser-Doppler-based equipment
Large spectrum of microscopic methods (darkfield, phase contrast, ...)
Completely computer-controlled measurement and automatic titration
|A detailed knowledge of the electrical and steric structure of particle- electrolyte interfaces is important for characterizing and controlling the surface behaviour of particles in fields such as colloid and polymer chemistry, biotechnology and biomedical applications. The HaSoTec ELECTROPHOR is an electrophoretic instrumentation based on a real-time image processing system.
|It was developed for measurements of electrophoretic mobilities, electrophoretic fingerprinting and multi-parameter analysis of cells and other particles. A new tracking procedure allows measurements of the electrophoretic mobility, size, density (sedimentation) and shape of every single cell. The following examples describe new features and typical applications of the HaSoTec ELECTROPHOR such as detection of different populations, measurement of small differences between fingerprints, multi-parameter analysis of cells and comparison between theoretical and experimental electrophoretic fingerprints. Each cycle of a measurement captures up to 128 video frames. These frames are simultaneously visible in a window. Particles which confirm to user-defined object specification to be measured are shown with a cross marker overlay.
|Fig. 2 shows an online mobility histogram updated by the ELECTROPHOR after each measurement cycle. The histogram is automatically scaled to reflect all measured particles. Status lines show additional values such as the actual number of particles, mean and peak value of electrophoretic mobility (EPM), standard deviation, pH, temperature, electric voltage, conductance and drift. Multi-parameter analysis is a new key feature, available for the first time with HaSoTec´s ELECTROPHOR. This is impossible for Laser-Doppler-based equipment, which is limited to detecting a spectrum of particle groups. The ELECTROPHORs video analysis allows simultaneous measurements of several parameters on a particle- by- particle basis. This opens new possibilities for measuring mixed particle suspensions, e.g. to discriminate between normal and pathological cells, and it improves the reliability and accuracy of a measurement. Combining 2D-plots and 3D-plots with statistical methods makes for a powerful new method of making visible even slight differences between particles.
|2D- graph of electrophoretic mobility (10-8 m2s-1V-1) versus size (arbitrary units) in the case of cells obtained from the peritoneal dialysate of a patient with peritonitis. /// Acute state, 2 weeks later, \\\ 6 weeks later. The regions of different cell types differ by size and mobility: 1-macrophages, 2- granulocytes, 3-lymphocytes, 4-erythrocytes. The ELECTROPHOR measures electrophoretic mobility in relation to pH and conductivity of the electrolyte in a wide range. Electrophoretic titration data measured in solutions with different sodium chloride concentrations are not regularly distributed in the pH-conductivity plane.
|For this reason, values for an equally spaced grid have been calculated from the measured data using an inverse distance method followed by splining (elemination of possible irregularities). The experimental electrophoretic fingerprints may be represented in a system of pH / conductivity / electrophoretic mobility or pH / inverse Debye radius / aparent charge. Electrophoretic fingerprinting is becoming more and more important for the characterization of particle surfaces. The procedure mentioned above is important for making fingerprints comparable, presenting the data as 3D-surfaces and 2D-fingerprints. From the 3D-fingerprint data it is possible to calculate gradients and differences of fingerprints. This figure shows the differential of the partial derivation EPM/ pH based on measured data from treated and non-treated human erythrocytes.
|ELECTROPHOR's basic configuration consists of a built- in Nikon Optiphot / Labophot, temperature controlled electrophoresis chamber, TV camera, video digitizer, AT/PCI computer, sample loader and automatic titration device. ELECTROPHOR can measure mobility, size, shape, sedimentation, 3-D center of mass, intensity, fluorescense, conductivity, pH, temperature, inner electrode voltage, outer electrode voltage and chamber current. All functions are computer-controlled.
|Advantages of the HaSoTec ELECTROPHOR over Laser-Doppler devices:
|Online view of the microscopic image on the computer monitor
WYSIWYG. All measured particles are shown on screen with cross markers
Object filters allow one to measure selected particles according to a given parameter range.
Multiparameter measurements allow one to distinguish cells and particles without other separation procedures, which may change the particle characteristics - Capability of investigating non-Gaussian distribution of particle mobilities, e.g. in mixed cell populations
Measurement of the sedimentation of the cells allows for the calculation of their density
Particle-by-particle data allow better statistical characterization and distinction of measurements
Optimized characteristics for "large" (~10 µm) and "small" particles using darkfield microscopy
Determination of the particle mass using optional analysis of Brownian motion
|This project was realized with the help of Bundesministerium für Forschung und Technologie. Special thanks for fruitful discussions and hints during the development phase to University of Rostock, Dr. Ruhmann & Partner Technologieberatung, Nikon GmbH, Carl Zeiss Jena GmbH and especially to Dr. Knippel and Dr. Schöppe. All trademarks are trademarks of their respective owners.
© HaSoTec GmbH, all rights reserved. Developed and manufactured by HaSoTec GmbH Rostock, Germany.