DE19952322A1 - Method and device for particle separation - Google Patents

Abstract

The invention relates to methods and devices for particle separation, according to which, in a fluidic microsystem consisting of a particle mixture (1), target particles (2) with predetermined characteristics are separated from residual particles (3) in a plurality of particles. Said procedure consists of the following steps: the particles of the particle mixture (1) are positioned in observation fields on functional elements (30) in at least a first receiving structure (10) of the microsystem (100), the functional elements being configured to hold the particles at least temporarily; the particles are measured in the observation fields in order to determine the particle characteristics and the observation fields which contain the target particles (2) or the residual particles (3) are recorded; optical cages are created on the observation fields which contain the target or residual particles using at least one light modulator that allows at least one optical cage to be switched on or off and the target or residual particles are simultaneously or successively transferred from their respective observation fields into at least a second receiving structure (20) of the microsystem, with optical forces of the optical cages interacting with forces of the functional elements (30).

Description

The invention relates to a method for separating particles mixtures according to certain particle properties, in particular a separation process for mixtures of microscopic particles in fluidic microsystems, and a separation device for Execution of the procedure.

Often used in biological or medical examinations gene, in diagnostics and in biotechnological processes The task is to separate the suspension ge mix by distributing or sorting cells or Mi croparticles from a large starting quantity into certain Groups with the same characteristics. For example The transfection of a cell line can often only be incomplete be carried out so that before further processing or use this cell line to successfully transfect it Separate cells from unsuccessful cells Need to become. Sorting in particular rarely occurs Individuals places very high demands on this Separation process with regard to the purity and homogeneity of the Target fraction. Another example in the medical field is given with the bone marrow transplantation, with the stem cells are separated from a large number of other cells have to. Also when analyzing fetal cells in the maternal chem blood must have a few fetal cells from the cells be separated mixture that is in the mother's blood finds. An important task in tumor diagnostics is Detection, sorting and analysis of metastasia cancer cells in the patient's blood. They are different ne methods for the separation of cell mixtures known, the Solve separation task only imperfectly. Which includes  especially affinity chromatography, separation processes based on fluorescent labels such as fluorescence-activated cell sorting (FACS), on which Ba sis of marking with ferromagnetic particles, the Ma gnet activated cell sorting (MACS) and microscopic ver drive.

Affinity chromatography as well as MACS (or: Pan ning processes) are limited to separation processes in which the cells on the cell surface express a molecule that an affinity for another, known or unknown Possesses substance. In affinity chromatography, the on a chromatography matrix, for example the base of beads. A suspension of the tren cells is given over this matrix, so that the ex priming cells adhere to it while the other cells be washed away. The disadvantage of this method is in addition to the limitation to cellular systems with an upper Area expression of molecules, in the high mechanical Strain on the cells and the poor selectivity of the chroma tography. The selectivity is poor because there are many cells low affinity hang unspecifically on the matrix, which are not actually part of the cells to be separated. In in practice is affinity chromatography on the separation limited by bacteria that are not mechanically sensitive.

When cells are magnetically activated, the cells become pension with micrometer-sized magnetic particles, on which the af fine substance is applied, mixed and the magnetic particles along with the target cells using an outside of the reak tion vessel located magnets separated. Here too the spread of unspecific adherent cells to the Ma gnetparticles a considerable limitation of the process visually the purity of the target fraction.  

When using fluorescence-activated cell separation (FACS) this in a liquid flow through a thin capillary transported, usually another, cell free envelope flow is provided. This current is from one Drop generator disassembled into single drops from the Kapil lare be emitted into a free measuring room. The drops pass an optical measuring section in flight, in which one of them Scattered light and / or fluorescent light measurement who subjected the. For this, one or more lasers on the trajectory of the Drops focused in the optical measuring surface. The measured Scattered light and / or fluorescence intensities allow that Determine whether certain cell properties exist or not. Depending on the measurement result, one after the Measuring section arranged distribution device, for example the base of a mechanical baffle plate or an elec trostatic deflector, operated.

The disadvantage of fluorescence-activated cell separation is in that it is a serial process. The optical effort for the test section is so great that a par allelization is too complex for practical applications. The same applies to the drop generation and the distribution learning facility. For example, 10,000 cells per second To be able to analyze must be in a serial procedure the measurement time may be limited to 100 ms or less. In the Measurements are possible in short time ranges, however also with relatively large errors, so that the separation sharpness of the process is adversely affected.

Microscopic cell separation is based on two dimensional layer of cells (so-called cell lawn) to bil and scan it with a microscope. From every cell a picture taken, which an image evaluation for the Feststel is subjected to predetermined cell properties. Depending on a picking device is used to evaluate the result  individual cells after measurement from the cell lawn too solve and deliver to a destination. A particularly high resolution solution in image acquisition is achieved by using the confocal Microscopy achieved. This method also has limitations especially regarding the throughput of the picking device tung. Without damaging cells, the maximum rhythm can be A picking process takes approx. 10 s each, which is moreover represents a mechanical load on the cells to be separated.

The problems mentioned do not only occur when separating from Cell mixtures, but generally when separating parti mixed natural and / or synthetic origin.

FIG. 7 illustrates a principle of the distribution of particles which is generally known from microsystem technology. A fluidic microsystem 100 'contains a first channel structure 10 ' and a second channel structure 20 'which adjoin one another, for example, channels or chambers arranged side by side or one above the other. A particle mixture 1 'suspended in a liquid is moved in the first chamber structure 10 ' to a field cage 30 '. As soon as a particle is positioned in the field cage 30 ', a measurement of the particle with electrical means takes place at this observation position and, after the particle has been released from the field cage 30 ', depending on the measurement result, a deflection electrode 40 'is driven such that the particle enters the second channel structure 20 'transferred or for further movement in which it most channel structure 10' remains (see arrows). This method is disadvantageous because of the serial separation method. If the separation process shown in FIG. 5 with a plurality of field cages Runaway leads are, several deflecting electrodes would have to be selectively tune accordingly. However, due to the electrical interaction of adjacent structures, this cannot be reliably carried out in practically interesting time ranges and undesirable fault separations would occur. Another disadvantage is the limitation to the measurement of electrical properties of the particles in the microsystem.

The object of the invention is an improved Trennver drive indicate that is characterized by a high throughput, a high selectivity and low mechanical stress distinguishes particles to be separated. The object of the invention is also to implement a separator to specify such procedure.

These tasks are solved by a method and a device with the features according to the patent claims 1 and 17 , respectively. Advantageous embodiments and applications of the invention result from the dependent claims.

The basic idea of the invention is to separate particles to perform in a fluidic microsystem in which the particles to be separated are initially separated individually or in groups in a variety of functional elements based on Field cages or other suitable field barriers through nega tive dielectrophoresis positioned and on this observer measurement position (or: in this observation field) become. When measuring, predetermined properties of the particles to be separated and, accordingly, the positions of the Determines particles to be separated from the mixture or the positions of the particles that belong to the residual mixture. in the The present description will separate them the particles also target particles and the rest of the mixture belonging particles called residual particles. To the target or Residual particles in an adjacent channel structure of the microsy stems to transfer the target or residual particles the measurement individually or simultaneously of laser radiation undergo an optical cage to form each. The Laser radiation can occur within a field cage a field barrier or in the flow direction immediately behind  a field cage or a field barrier. Dementia The target or residual particles are added to the electrical field forces also exposed to optical forces. Depending on the embodiment of the invention, the transmission takes place the target or residual particles by shifting the optical Cages in the adjacent channel structure or by opening the electrical field cages to the adjacent channel structure while holding the optical cages at the same time. This Transfer can also be for multiple target or residual particles done simultaneously. The target particles are made accordingly in the neighboring or in the original channel structure of the microsystem and processed further.

According to a basic form of the invention, the Target or residual particles in two groups. By gradual Repeat the separation with reference to other parties sorting into multiple target or Residual particle groups take place.

A device for particle separation in fluidic microsys according to the invention comprises a first channel structure Electrode devices for forming a variety of functions on elements (e.g. dielectric field cages) an adjacent, second channel structure that at the positions of the functional elements elements connected to the first channel structure via openings is a laser device used to form optical cages is formed in each dielectric field cage, and one Light modulator device with the in any given position tion of the respective optical cage individually on or off can be switched.

According to a first embodiment of the invention, the Transmission of the target particles by switching on the optical Cages in or behind the field cages or field barriers the target particles, capturing the target particles in the optical  Cages and moving the optical cages to the second Channel structure while the residual particles in the first channel stay structure. The second channel structure is either which is parallel to the first in the y direction (relative to the Direction of flow of the particle stream). In this case there is a shift in the cages in the optical cages particles by moving the device in xy- Direction relative to the optical axis of the laser beam. Or the second channel structure lies in the z direction along the opti cal axis above the first channel structure. In this case ge moves the particles through to the second level Focus adjustment of the optical cages.

According to a second embodiment of the invention, the Target particles also in the respective dielectric field cages kept in optical cages while the rest of the parties unlit in the other dielectric field cages and thus remain free of optical forces. For particle separation all field cages are detuned in such a way that dielectri cal repulsive forces are formed on the particles in the field cages directed towards the second channel structure are. Thereupon the remaining particles are in the second channel structure transferred while the target particles are under effect the optical forces despite the field cage detuning in the first channel structure remain.

The invention has the following advantages. With the invent principle of serial or parallel measurement according to the invention a large number of particles with a subsequent parallel The throughput of the particles becomes the transmission of the target particles Separation compared to conventional techniques Lich increased. Measurement of particles in the dielectric Field cages can be handled gently without any adverse effects the particles are carried out. Stands for the survey enough time to find the properties you are looking for  to reliably determine the particles. In particular sorting out rare particles in one large starting population can thus be highly reliable because all particles can be individually addressed. The dielectric field cages or field barriers separate them separate particles spatially apart during the procedure. The optical cages enable the detection of individual particles without crosstalk to other particles. This will separate Sharpness of particle separation significantly improved. The Vermes solution can affect electrical and / or optical properties of the particles. The invention is with any part can be implemented of natural or synthetic origin, that can be manipulated in fluidic microsystems. A white Another advantage is the compatibility of the separation process rens with the available microsystem technology.

Further advantages and details of the invention will become apparent from the following description of the accompanying drawings Lich. Show it:

Fig. 1 is a schematic plan view of a microsystem according to the invention with a separating device,

Fig. 2 shows a schematic side view of a microsystem according to FIG 1.

Fig. 3 shows a schematic top view of a microsystem according to the invention with a further separating device,

Fig. 4 is a schematic side view of a microsystem according to FIG 3.

Fig. 5 is a schematic top view of a microsystem with a two-dimensional, two-dimensional matrix array of field cages, and a rule for the inventive embodiment typi airfoil,

Figure 6 is a schematic plan view of a barrier micro system with a two-dimensional, two-dimensional matrix array of field, and.

Fig. 7: a schematic plan view of a conventional single particle distributor (prior art).

A first embodiment of the invention, which is illustrated in FIGS . 1 and 2, is based on the combination of dielectric field cages with adjustable optical cages. A separating device 200 according to the invention, which is integrated in a fluidic microsystem 100 , comprises a plurality of dielectric field cages 30 , in each of which an optical cage with adjustable focus 41 is formed with the laser device 40 and the optics 42 . Reference numeral 43 indicates a light modulator with which the optical cages in the field cages 30 can be selectively switched on or off.

The creation of optical cages and their use for mani pulverization of microscopic particles is known per se (See, e.g., A. Ashkin et al. in Nature, Vol. 330, 1987, Pp. 796 ff., And G. Weber et al in "International Review of Cytology ", vol. 133, 1992, pp. 1 ff.). Details of the laser operational (e.g. power, wavelength etc.) and the beam fo kissing can be in the implementation of the invention Systems based on the known techniques to the kon Crete separation task can be adjusted.

The microsystem 100 comprises at least two channel structures 10 , 20 . The channel structures 10 , 20 each comprise micro channels or micro chambers with an application-dependent selected shape. In the example shown, two channels arranged one above the other in the operational function are provided, for example. But they can also be arranged side by side. The channels are made of plastic, gas or semiconductor materials using methods known per se from microsystem technology and are designed to be flowed through by liquids with suspended particles. The channels have characteristic dimensions, which are selected depending on the application so that an unimpeded suspension throughput is possible. If the microsystem is used, for example, to manipulate biological cells (characteristic size: 10 µm), each channel has a typical cross section that is larger than 10 µm and, for example, up to 50 µm. To separate synthetic particles (beads), for example in applications in combinatorial chemistry, the channels can also have characteristic cross-sectional dimensions in the range from 100 to 200 µm. In order to guarantee an optical particle measurement in the field cages, the walls of the microsystem 100 are designed to be at least partially transparent.

A multiplicity of field cages 30 are formed in the first channel structure 10 of the microsystem 100 . Each field cage 30 comprises a group of schematically illustrated microelectrodes 31 , which are attached to the top and bottom surfaces of the respective channel structure. The microelectrodes 31 are designed to be exposed to high-frequency fields in such a way that there is a field distribution between the microelectrodes 31 in which polarization forces are generated on dielectric particles which hold the particles inside the field cage. Details of the construction and control of dielectric field cages and field barriers are known per se (see BG Fuhr et al. In "Electromanipulation of Cells", CRT Press Inc., 1996, p. 259 ff.).

In the microsystem 100 , a charging device 50 is also provided, which is designed to distribute particles to the field cages 30 of the separating device 200 . The loading device 50 , the function of which will be explained in detail below, is however not a mandatory feature of the invention and can alternatively also be replaced by other loading or aligning members.

The loading of the observation positions or fields can, for example, also be carried out passively by transporting the particle suspension via the laminar liquid flow. The flow profile in the microchannels of the device is not parabolic, but runs straight across most of the channel - with the exception of the outermost edge regions (see FIG. 5), since the channel is considerably wider than it is high. In this way, the particles are transported uniformly quickly over the major part of the channel and the field cages or field barriers are statistically evenly loaded. Deflection electrodes 63 on the edge of the channel serve to convey particles from the flow-reduced edge zones of the channel into zones with a uniform flow. The deflection electrodes can also be part of field cage or field barrier electrodes. If an observation position remains unoccupied, this is irrelevant for the further procedure.

The channel structures 10 , 20 , apart from openings 11 in the area of each field cage 30 , are separated from one another by a continuous wall. The object of the separation method is now to separate a particle mixture 1 flowing into the first channel structure 10 in the direction of the arrow A into target particles 2 , which are to be transferred into the second channel structure 20 in this embodiment of the invention, and to separate residual particles 3 which the first channel structure 10 should remain ver. So first the particles 2 individually or in groups z. B. using the charging device 50 in the arranged in a row (see Fig. 1) arranged observation positions (field cages or field barriers) 30 loaded. The charging device 50 comprises two straight, arranged on the upper and lower channel sides, strip-shaped microelectrodes which exert repulsive forces on the inflowing particles when exposed to high-frequency electrical fields under the effect of negative dielectrophoresis and thus form a field barrier which runs obliquely to the direction of flow (arrow A) . When the field barrier is switched on, the first inflowing particle 1 a initially runs along the arrow direction B to the end of the charging device 50 and then into the field cage 30 a (see FIG. 2). In this state, the field cage 30 a is open on the upstream side, so that the particle freely reaches the center 31 a of the field cage 30 a. As soon as the arrival of the particle is detected, for example with optical or elec trical means, the field cage 30 a is also closed on the upstream side. The remaining field cages 30 b, 30 c,. , , are loaded analogously by inflowing particles. The loading device 50 is actuated in synchronism with the loading condition of the field cages. At the Ladeeinrich device 50 , further alignment elements, field cages or barriers are optionally provided for arranging the inflowing particles.

When all field cages are loaded with particles, the Measurement to determine physical and / or biological chemical parameters of the particles. This measurement takes place for example optically (for example fluorescence or scattered light measurement) and / or by electrical means (for Example of electric rotation measurement in the field cages). It can also be provided with the suspension liquid in the micro system to flush additives to the field cages, their change interaction with the held particles optically and / or is detected electrically. The field cages in which the Target particles with predetermined parameters are used Preparation of the following separation step.  

For the simultaneous transmission of the target particles into the second channel structure 20 , the light modulator 43 is actuated in such a way that laser radiation is released into the detected field cages with the target particles. An optical cage is formed by this irradiation, the focus 41 of which coincides with the center (eg 31a) of the dielectric field cage 30 . The target particles are caught in the optical cages like with laser tweezers. Subsequently, for all optical cages, the focus 41 is simultaneously shifted through the opening 11 between the channel structures (arrow C). This shift takes place, for example, by adjusting the optics 42 . As soon as the target particles with the shifted focus have been transferred into the second channel structure 20 , the laser radiation is switched off with the light modulator 43 . The target particles are thereby released in order to be subjected to further movement and / or processing in the second channel structure 20 . Simultaneously, the field cages 30 are opened in the first channel structure 10 on the downstream side, so that the residual particles 3 are also released to who. The target or residual particles 2 , 3 can each be subjected to one or more further separations according to the principle explained, in order to sort them into a large number of particle groups.

The separating device 200 in particular comprises the laser device 40 , the light of which is bundled with the optics 42 to form the focus 41 , and the light modulator 43 . The Lasereinrich device 40 comprises a laser diode arrangement or a single laser with a beam expansion optics. It can also be seen before several laser beams to form an optical cage. In the laser diode arrangement, a large number of laser diodes are aligned in accordance with the position of the field cages or field barriers in the microsystem. When using a single laser, however, the entire arrangement of the field cages is illuminated with the single expanded beam. The laser device 40 is preferably operated at a wavelength which is particularly well suited for the formation of effective optical cages with the lowest possible light output. For most applications, the wavelength is selected in the infrared or red spectral range.

The light modulator 43 is a transmission or reflection modulator. Known microshutter arrangements can be used as the transmission modulator, in which a large number of microshutters are aligned according to the position of the field cages. Mechanical microshutters or switchable liquid crystal arrangements are used. A switchable matrix of mirror elements (so-called digital mirror array) can be used as the reflection modulator. Alternatively, if the laser device 40 is designed with a laser diode arrangement, it is also possible to integrate the light modulator into the laser device 40 . In this case, the light modulator is a control circuit with which the individual laser diodes can be switched on and off individually.

The optics 42 comprises a microlens arrangement from a variety of microlenses, which are aligned according to the positions of the field cages. The microlens arrangement is vertically movably mounted for adjusting the focus 41 , as is known per se from laser tweezers.

According to a preferred embodiment, the particles in the field cages are measured using an optical detector device, which is formed, for example, by an array detector based on CCD, CID, CMOS-APD or PD arrangements. The detector device is preferably mounted on the opposite side of the microsystem 100 relative to the laser device 40 . The detector elements of the detector device are preferably designed for wavelength-selective light detection. For this purpose, filter devices, which may be integrated into the detector device, are provided. The wavelength-selective measurement is used in particular to measure the fluorescence on the particles.

Another embodiment of the invention, which can also be implemented with the arrangement illustrated in FIGS . 1 and 2, is based on the combination of optical cages with adjustable dielectric field cages. In this design, as described above, the particles of the starting mixture 1 are first positioned and measured in the field cages 30 . In order to separate the target and residual particles from each other, depending on the measurement result for a group of field cages 30 , which contains, for example, the target particles, the laser irradiation is released with the light modulator 43 . This traps each target particle in an optical cage. To separate the particles, all field cages 30 are now detuned in such a way that a resulting dielectric force is exerted on the particles through the opening 11 into the second channel structure 20 . This force effect follows all particles that are not additionally held by the optical cage, so that there is a corresponding collection in the second channel structure 20 . In this case, the illuminated particles (e.g. target particles) remain in the first channel structure 10 . After the optical or dielectric forces have been released, the target or residual particles are transported further in the first or second channel structure 10 , 20 .

A further modified embodiment of the invention, the corresponding one of the two above-mentioned Kombinationsprin ciples can be operated, in Figs. 3 and 4 illu strated. The microsystem 100 in turn contains two channel structures 10 , 20 arranged one above the other with at least partially transparent channel walls. Depending on the application, microelectrodes designed to produce field cages and / or barriers are formed on the inner top or bottom surfaces of the channel structures. In contrast to the field cage row shown in FIG. 1, the separating device 200 in this embodiment comprises a flat matrix arrangement of field cages 30 in straight rows and columns. Several rows of observation positions are arranged one behind the other in the direction of flow. On the one hand, this has the advantage that individual particles can be evaluated several times in succession, which considerably improves the reliability of the analysis and thus also the separation. On the other hand, such a two-dimensional array of observation fields significantly increases the throughput of particles that are evaluated at the same time.

A further modified embodiment of the invention with regard to the shape of the electrodes for the formation of field cages 60 is shown in FIG. 5. Here, the individual field cages are formed by tine or comb-like electrodes ( 61 a, 61 b, 61 c... ) educated. The particles 62 a, 62 b, 62 c. , , arrange themselves in such an arrangement in the spaces between the tines. This electrode shape has advantages in terms of simple electrode processing with connected lines.

Another modification of the invention is shown in FIG. 6. No complete field cages are formed here, but field barriers 70 using electrodes, as at 70a, 70b, 70c. , , shown. The particles 71 a, 71 b, 71 c. , , who is pressed by a steady flow of liquid 72 against the dielectric field barriers and thus held at the respective observation positions.

According to the invention, different directions of the irradiation by the laser device 40 can be provided. According to FIG. 4, the irradiation from the bottom of the micro-system is carried out, that is, from the side of the first channel structure 10. forth. Accordingly, at least the channel floor 12 consists of a transparent material. An optical measurement of the particles trapped in the field cages 30 can also be carried out from the underside of the microsystem 100 or from the opposite side. The light from the Lasereinrich device 40 is in turn focused via a light modulator 43 and an optics 42 in the field cages 30 .

In the embodiments shown in FIGS . 3 and 4, a line-up of field cages is seen as loading device 50 . The flowing in the first channel structure 10 Parti kel 1 (mixture to be separated) are first positioned in the loading device 50 . As soon as each field cage 51 of the loading device 50 contains a particle, the entire row of field cages 51 and the adjacent row of field cages 30 a are controlled so that the particles are taken over into the field cages 30 a. Then the field cages 51 of the loading device 50 are loaded again. Again, the particles are passed on to the field cages 30 a and from there to the row of the field cages 30 b until gradually all rows of the field cages 30 are filled. The particles are then measured and separated according to the principles explained above.

An important advantage of the embodiments of the invention shown in FIGS . 1 to 6 is that all dielectric field cages are controlled simultaneously. Interference fields or crosstalk between the field cages are thereby avoided, as a result of which the accuracy of the separation according to the invention is considerably improved, in particular in comparison with the conventional technology explained with reference to FIG .

According to a further embodiment of the invention, the Particle separation only under the effect of optical Powers. In this (not shown) embodiment who the particles to be separated are not in dielectric fields fig, but on mechanically trained brackets in the Mi cross system positioned. Such brackets are used for example formed by holes in the channel wall. To the particle measurement is the group of target particles in appropriate optical cages added and with these by the brackets lifted away into the adjacent channel structure.

In a further modification of the separation print explained above zips is provided that three channel structures to each other be are arranged adjacent, the positioning and measuring the particles in the middle channel structure and the over carry target particles into the adjacent channel structure is done by first creating a first group of target particles e.g. B. in the upper channel structure and then another Transfer group of target particles into the lower channel structure will.

Claims (27)

1. A method for particle separation, in which target particles ( 2 ) with predetermined particle properties are separated from residual particles ( 3 ) from a particle mixture ( 1 ) from a large number of particles in a fluidic microsystem, with the steps:

• - Positioning particles of the particle mixture ( 1 ) in observation fields on functional elements ( 30 ) in a he most channel structure ( 10 ) of the microsystem ( 100 ), the functional elements having electrode arrangements on which inhomogeneous electric fields are generated, the repulsive or attractive dielectrophoretic forces exert on the particles,
• - Measuring the particles in the observation fields in order to determine the particle properties and to detect the observation fields which contain the target particles ( 1 ) or the residual particles ( 3 ),
• - Forming optical cages on the observation fields, which contain the target or residual particles, using a light modulator device with which the optical cages can be switched on or off individually, and
• - Simultaneous transfer of the target or residual particles from their respective observation fields into an adjacent two-th channel structure ( 20 ) of the microsystem, optical forces of the optical cages and dielectric polarization forces of the functional elements ( 30 ) interacting.

2. The method according to claim 1, in which for transferring the particles, the focal points ( 41 ) of the optical cages with the target or residual particles are simultaneously moved from the first into the second channel structure ( 20 ), while the respective remaining particles in the first Channel structure ( 10 ) remain. 3. The method according to claim 1, wherein the functional elements are used as electrical field cages ( 30 ). 4. The method according to claim 3, in which to transmit the particles, the dielectric field cages ( 30 ) are opened on one side towards the second channel structure ( 20 ) and the target or residual particles with the optical cages are held in the dielectric field cages while move the remaining particles into the second channel structure ( 20 ). 5. The method according to any one of the preceding claims, in which to measure the particles optical measurements and / or elec measurements are carried out. 6. The method according to claim 5, wherein the optical measurements Fluorescence and scattered light measurements include. 7. The method according to claim 6, in which to the optical measurement a laser device is used, which is also used for bil is designed for the optical cages. 8. The method according to claim 5, wherein the electrical measurement solutions include electrical rotation measurements on the particles. 9. The method according to any one of the preceding claims, in which a microshutter arrangement and / or a switchable matrix of mirror elements on the respectively detected functional elements or dielectric field cages ( 30 ) with the target or residual particles is actuated as the light modulator device for forming the optical cages. 10. The method according to any one of the preceding claims, at which the particles are suspended in a liquid that with a liquid transport system through the microsystem is promoted. 11. The method according to claim 10, wherein the liquid speed transport system a syringe pump, a peristaltic Pump, a diaphragm pump, a gear pump, an electroosmo table pump and / or a piezoelectric pump used become. 12. The method according to any one of the preceding claims, at which the particle flow forces and electrical forces of Electrode assemblies are exposed to the particles lined up and / or isolated to the observation fields ren. 13. The method according to any one of the preceding claims, in which the target or residual particles ( 2 , 3 ) are transferred after the particle separation into different collecting units. 14. The method according to any one of the preceding claims, at where the particles are synthetic particles, biological cells, Cellular assemblies, cell components, macromolecules, macromolecules volumes, bacteria, viruses, alginate beads or composite particles made of synthetic and natural parts. 15. The method according to claim 14, wherein the particles are spherical cal polymers (beads) made of organic (e.g. polystyrene, algi nat) or inorganic (e.g. silica gel) material, eukarioti procariotic or cells, cell aggregates and / or aggre Gate of these include, the aggregates both from the same Chen as well as different species can exist.   16. The method according to claim 15, wherein the particles before the Introducing into the microsystem or in the microsystem with one magnetic or a fluorescent probe substance mar be cated. 17. Separating device for separating a particle mixture ( 1 ) from target particles ( 2 ) with predetermined particle properties and residual particles ( 3 ) in a fluidic microsystem, comprising:

• - A first channel structure ( 10 ) with a plurality of func tion elements ( 30 ) and a charging device ( 50 ) for posi tioning particles of the particle mixture ( 1 ) on the func tion elements ( 30 ),
• a second channel structure ( 20 ) which is connected to the first channel structure ( 10 ) at the positions of the functional elements ( 30 ) via openings ( 11 ),
• - A laser device ( 40 ) which is designed to form an optical cage on each functional element ( 30 ), and
• - A light modulator ( 43 ) with which the optical cages on the functional elements ( 30 ) can be switched on or off.

18. Separating device according to claim 17, in which an adjustable optical system ( 42 ) is provided with which the focal points ( 41 ) of the optical cages of the functional elements ( 30 ) in the first channel structure ( 10 ) in the second channel structure ( 20 ) are adjustable are. 19. Separating device according to claim 17 or 18, wherein one Measuring device for determining optical and / or electrical Particle properties is provided. 20. Separating device according to claim 19, wherein the Meßvor direction comprises a detector device which is arranged relative to the laser device ( 40 ) on the opposite side of the microsystem ( 100 ). 21. Separating device according to one of claims 17 to 20, wherein the light modulator ( 43 ) comprises a microshutter arrangement or a switchable matrix of mirror elements. 22. Separating device according to one of claims 17 to 21, wherein the functional elements include electrode arrangements for generating inhomogeneous electric fields which exert repulsive or attractive de dielectrophoretic forces on the particles in the first channel structure ( 10 ). 23. Separating device according to claim 22, in which the electrode arrangements form electrical field cages ( 30 , 60 ) or electrical field barriers ( 70 ). 24. Separating device according to one of claims 17 to 23, the a liquid transport system based on a syringe pump, a peristaltic pump, a diaphragm pump, one Gear pump, an electroosmotic pump and / or one has piezoelectric pump. 25. Separating device according to one of claims 19 to 24, at which the measuring device has an optical array detector on the The basis of a CCD, CID, CMOS, APD or PD array is. 26. The separator of claim 25, wherein the array Detector comprises a plurality of detector elements which too at least partially provided with wavelength-selective layers are. 27. Use of a method or a separator according to one of the preceding claims for the separation of par particle mixtures in fluidic microsystems.