Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
  • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
  • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
  • B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
  • B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
  • B01L3/502769—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by multiphase flow arrangements
  • B01L3/502784—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by multiphase flow arrangements specially adapted for droplet or plug flow, e.g. digital microfluidics
  • B01L3/502792—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by multiphase flow arrangements specially adapted for droplet or plug flow, e.g. digital microfluidics for moving individual droplets on a plate, e.g. by locally altering surface tension
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
  • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
  • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
  • B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
  • B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
  • B01L3/502707—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by the manufacture of the container or its components
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
  • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
  • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
  • B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
  • B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
  • B01L3/502746—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by the means for controlling flow resistance, e.g. flow controllers, baffles or throttle valves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B19/00—Machines or pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B1/00 - F04B17/00
  • F04B19/006—Micropumps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
  • B01L2300/00—Additional constructional details
  • B01L2300/08—Geometry, shape and general structure
  • B01L2300/0887—Laminated structure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
  • B01L2300/00—Additional constructional details
  • B01L2300/16—Surface properties and coatings
  • B01L2300/161—Control and use of surface tension forces, e.g. hydrophobic, hydrophilic
  • B01L2300/165—Specific details about hydrophobic, oleophobic surfaces
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
  • B01L2400/00—Moving or stopping fluids
  • B01L2400/04—Moving fluids with specific forces or mechanical means
  • B01L2400/0403—Moving fluids with specific forces or mechanical means specific forces
  • B01L2400/0415—Moving fluids with specific forces or mechanical means specific forces electrical forces, e.g. electrokinetic
  • B01L2400/0427—Electrowetting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
  • B01L2400/00—Moving or stopping fluids
  • B01L2400/08—Regulating or influencing the flow resistance
  • B01L2400/084—Passive control of flow resistance
  • B01L2400/088—Passive control of flow resistance by specific surface properties
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
  • F05C2225/00—Synthetic polymers, e.g. plastics; Rubber
  • F05C2225/04—PTFE [PolyTetraFluorEthylene]

Definitions

• the present invention relates to a drop handling device for biochemical analysis, a method of manufacturing such a device, and a microfluidic analysis system using such a device.
• proteomics an activity related to the identification and study of proteins, tries to use new technologies to reduce sampled volumes that are handled, and to reduce contamination.
• the objective is, in a general way, to control the micromanipulation of the material, before spectrometric analysis for example.
• the problematic of the control of fluid flows is strategically important insofar as the material, for example proteins, can not be handled outside a liquid medium.
• the invention thus relates to the field of microfluidics, which more generally concerns flows in systems of micrometric or nanometric size, in which the sample handled can be subjected to electric fields or wall effects of a physical or chemical nature. complex, and in which the high ratio surface / volume is of great importance.
• the displacement of calibrated microvolumes has a number of advantages. Indeed, it allows very small volumes of liquids and allows a suitable control of microvolume flow while the continuous flow pumping is characterized by a constant flow. Moreover, this type of movement allows various synchronizations that allow the mixing of liquids for example.
• different modes of action are known: by pneumatic action, by surface acoustic waves, with dielectrophoretic effect, by electrowetting, and by electrowetting on dielectric (EWOD). This last mode of action makes use of a relatively simple technological achievement and allows the control of the flow and the circulation of a calibrated volume of conductive liquid on a network of electrodes.
• the nonwettability and the wettability with respect to water are respectively the properties of hydrophobicity and hydrophilicity.
• a hydrophobic material is a non-wetting material with respect to water
• a hydrophilic material is a wetting material with respect to water.
• the wettability is generally characterized by the contact angle ⁇ between the drop 1 and the surface 2 (see FIGS. 1a to 1d). The wettability coefficient defined as the cosine of the above-mentioned angle is sometimes used.
• FIGS. 1c and 1d illustrate intermediate cases of wettability ( ⁇ ⁇ 90 °) or non-wettability ( ⁇ > 90 °), respectively.
• the problem posed by the non-wetting materials with respect to a liquid, in particular the hydrophobic materials, which are otherwise essential for the displacement, is that the surface properties of these materials prevent the creation of chemical surface treatment zones by the These materials are characterized by low surface energy. If one tries to localize the surface of such materials locally, which would allow the treated liquids to be treated chemically, the result is unreliable, difficult to control and too imperfect.
• the alternative of making the non-wetting material more rough with respect to the liquid is not conceivable because it makes the ability of the material to favor the transport of the liquid lose. It is therefore necessary to use a layer of material that is partially wetting, that is to say that it must maintain the non-wetting character for movement, while creating wetting or high wettability for functionalization.
• the layer of hydrophobic material is first subjected to a surface modification using of a plasma, to modify its hydrophobic properties, that is to say to make it less hydrophobic.
• This technique also poses the problem of permanently modifying the surface properties of the hydrophobic material.
• the invention relates, in a first aspect, to a device for handling drops on an electrowetting displacement plane which comprises at least one electrowetting displacement track and which makes it possible to chemically treat or interact with the droplet. simultaneously with its transport.
• the displacement track comprises at least two interdigitated electrodes which rest on an electrically insulating substrate and which are covered by an insulating dielectric layer.
• This set insulating substrate, electrodes, insulating dielectric layer, is covered with a partially wetting layer vis-à-vis the manipulated drops.
• the partially wetting layer is therefore a partially hydrophilic layer.
• the term "non-wetting, partially wetting or wetting" layer or material will be used for a respectively non-wetting, partially wetting or wetting layer or material. manipulated drops.
• the device of the invention comprises, in another variant embodiment, at least one counter electrode distinct from the first electrodes. This counter electrode may be a ground line which will then be located on, under or in the partially wetting layer.
• the device comprises a second track positioned opposite to and separated from the first track so that a space, intended to be filled by an immiscible electrically insulating fluid opposite the transported drop, is formed between the first and second tracks, the second track comprising a non-wetting layer directly in contact with the space thus formed.
• This non-wetting layer of the second track is possibly partially wetting.
• This non-wetting layer is also possibly covered with an upper layer which is either electrically insulating, semiconductive, or conductive.
• the second track comprises one or more counter-electrodes located between the non-wetting layer and the upper layer. It optionally comprises an insulating dielectric layer which will be located between said non-wetting layer and said one or more counter electrodes.
• the partially wetting layer of the first track and / or the second track comprises non-wetting areas and wetting areas, the wetting areas being reactive functionalized areas.
• the device for handling drops in a plane of the invention comprises two tracks separated by a space intended to be filled by an immiscible electrically insulating fluid with respect to the drop carried.
• the first track comprises an electrically insulating layer or substrate on which at least two interdigitated electrodes are based. On this set rests a non-wetting layer.
• the second track includes a partially wetting layer.
• the partially wetting layer of the first track and / or the second track includes non-wetting areas and wetting areas, the wetting areas being reactive functionalized areas.
• the first track also comprises an insulating dielectric layer between the electrodes and the non-wetting layer.
• the device in this embodiment variant comprises a ground line located on, under or inserted into the non-wetting layer.
• the second track comprises an electrically insulating upper layer, semiconductor, or conductive.
• the electrically insulating substrate of the first track is preferably transparent, such as a glass substrate.
• the wetting zones are biochemically functionalized and reactive. These wetting zones are preferably openings in non-wetting areas.
• the non-wetting material constituting the non-wetting layer and / or the non-wetting areas of the partially wetting layer is a tetrafluoroetylene polymer.
• the device of the invention advantageously makes it possible to manipulate a drop of liquid, by transporting it on a plane by electrowetting, on a single track or between two tracks facing each other, with or without the use of a counter-electrode, while acting chemically on the drop as it passes over chemically functionalized zones.
• the desired optimization is thus obtained: concentrate the preparatory treatments for a subsequent analysis in a microsystem, during transport, to avoid contamination and losses on very expensive samples and in small volumes, while taking into account the aforementioned constraints microfluidics.
• the invention relates to a method of manufacturing the aforementioned device, in which the creation of the partially wetting layer of the first or second track is derived from the so-called "lift off” technique used in microelectronics for create metal patterns.
• This technique of the "lift off” as it is known if it allows the deposition of the non-wetting layer in the last step, thus avoiding a detrimental surface treatment, is however not suitable for creating patterns in such a way.
• non-wetting material in particular a hydrophobic material, such as a tetrafluoroetylene polymer, because it does not make it possible to obtain wetting zones sharp and precise in this non-wetting material.
• the invention thus relates, according to this second aspect, to a manufacturing method of the aforementioned device, in which the creation of the partially wetting layer of the first or second track comprises the following steps: creation of a mask of photosensitive material by depositing the photosensitive material on a substrate, photolithography, then revealing the photosensitive material; depositing a non-wetting material on the mask; at least one annealing before dissolution; dissolution of the mask; at least one annealing after dissolution.
• the annealing temperature before dissolution is lower than the annealing temperature after dissolution.
• the first annealing before dissolution is followed by at least one other annealing at a temperature greater than that of the first annealing.
• the first annealing after dissolution is followed by at least one other annealing at a temperature higher than that of the first annealing.
• the dissolution of the mask is followed by rinsing.
• the nonwetting material deposited is a tetrafluoroetylene polymer.
• the method of the invention advantageously allows the creation of a partially wetting layer which contains sharp and precise wetting zones, adapted to a chemical functionalization, and which contains non-wetting areas which retain their high nonwetting properties necessary for transport of drops.
• the layer of non-wetting material is deposited in the last step and does not undergo surface treatment, so does not undergo any change in its surface properties.
• the invention relates, according to a third aspect, to a microfluidic analysis system of a liquid sample which comprises at least one least one means for preparing the sample, coupled to at least one drop handling device according to the invention and as mentioned above, itself coupled to at least one analysis means.
• the preparation means comprises one or more tanks or loading docks.
• the analysis means is a mass spectrometer, a fluorescence detector, a UV emission detector, or IR.
• the system according to the invention is optionally integrated into a microsystem that integrates itself one or more laboratory operations usually performed manually, and that will be called micro-laboratory.
• FIGS. 1a to 1d schematically illustrates the property of non-wettability or wettability of a surface with respect to a drop
• FIGS. 2a to 2r show schematically different variants.
• embodiment of the device according to the invention sectional views perpendicular to the direction of movement of the drop
• - Figure 3 schematically shows the displacement of a drop on a track of the device according to a first variant of production
• FIG. 4 shows diagrammatically the displacement of a droplet on a track of the device according to a second embodiment variant
• FIG. 5 schematically represents the method for creating openings in a non-wetting material according to the conventional photolithographic technique using a surfactant; in the resin,
• FIG. 6 schematically represents the process for creating openings in a non-wetting material according to the conventional photolithographic technique with plasma surface modification
• FIG. 7 schematically represents an alternative embodiment of the process for creating openings in a non-wetting material according to the invention
• FIG. 8 schematically illustrates the chemical functionalization of a wetting zone
• FIG. 9 schematically illustrates the chemical treatment of a drop of a sample during its displacement
• FIG. 10 shows schematically an alternative embodiment of the system according to the invention.
• Figures 2a to 2r show schematically different embodiments of the device of the invention (sectional views perpendicular to the direction of movement of the drop).
• the device comprises at least one track with a substrate 1, preferably but not necessarily transparent, for example Pyrex ® .
• a substrate 1 preferably but not necessarily transparent, for example Pyrex ® .
• interdigital electrodes 2 preferably but not necessarily transparent, for example Pyrex ® .
• FIGS. 3 and 4 The notion of interdigital electrodes will be specified below with reference to FIGS. 3 and 4.
• insulating dielectric layer 3 consisting for example of oxides or polymers.
• non-wetting layer 4 which is rendered partially wetting by the method of creating wetting openings 5 in the non-wetting material 4, which process will be described in more detail a little further with reference to FIG. 7.
• the device comprises a single track consisting of layers 1, 2, 3 and 4.
• the device of FIG. 2a makes it possible to implement a movement by electrowetting that does not require counter-electrodes. , which will be explained below with reference to FIG. 3.
• the devices of FIG. 2b each have a counter-electrode in the form of a ground line 6 placed on the partially wetting layer 4 (FIG. 2b) inserted into and not covered by the partially wetting layer 4 ( Figure 2c), or inserted into and covered by the partially wetting layer 4 ( Figure 2d).
• the devices of FIGS. 2b to 2d make it possible, for their part, to implement electrowetting displacement with a ground line for a counter-electrode, a displacement which will be described below with reference to FIG. 4.
• Figures 2e and following show alternative embodiments in which we add a second track formed of a non-wetting layer 7 itself covered with an upper layer 8 which can be either electrically insulating or electrically semiconductive or still electrically conductive .
• This second track is placed opposite the first, with use of shims 9 to maintain a displacement space 10 to be filled with an immiscible electrically insulating fluid with respect to the drop carried.
• the fluid filling the space 10 must actually be electrically insulating.
• the fluid in order not to interact with the drop carried, the fluid must actually be immiscible with respect to the liquid. It may be for example air or oil, in the case of a drop of aqueous solution.
• FIGS. 2f to 2h show variants of realization which are respectively based on the devices of Figures 2b to 2d which is added a second track as described above.
• the second track further comprises one or more counter-electrodes 11 inserted between the non-wetting layer 7 and the upper layer 8. Therefore, no ground line is used, unlike to the devices of Figures 2f to 2h, since the counter-electrode is present in the second track.
• the mode of displacement is however identical to that of Figures 2f to 2h.
• FIGS. 2j to 21 sectional views perpendicular to the direction of displacement of the droplet
• FIGS. 2f to 2h variant embodiments of FIGS. 2f to 2h
• the non-wetting layer 7 of the second track is rendered partially wetting by the method of creating wetting openings 5 in the non-wetting material 7 which will be described later with reference to FIG. 7.
• FIG. 2m describes an alternative embodiment based on that previously described in FIG. 2e with the following difference: the non-wetting layer 7 of the second track is rendered partially wetting by the process of creating wetting openings 5 in the non-wetting material wetting 7 which will be described later with reference to Figure 7.
• the variant embodiment of FIG. 2n is in turn derived from the variant embodiment of FIG. 2i with the following two differences: the non-wetting layer 7 of the second track is rendered partially wetting by creating wetting openings 5 in the non-wetting layer 7 according to the method which will be described below with reference to FIG. 7; and, to enable the biochemical functionalization of these wetting apertures without interactions with the counter-electrode (s) 11, an insulating dielectric layer 12 similar to that present in the first track is inserted between the partially wetting layer 7 and the counter-electrode (s) 11.
• the embodiment variant described in FIG. 2o relates to a device with two tracks.
• the first track differs from the first track of the preceding embodiments in that the non-wetting layer 4 which constitutes it is not partially wetting: no wetting opening is created in this non-wetting layer 4.
• this variant embodiment does not require an insulating dielectric layer between the interdigital electrodes 2 and the non-wetting layer 4 in the case where this non-wetting layer 4 is itself electrically insulating. This is particularly the case for a hydrophobic layer made of a material such as a tetrafluoroethylene polymer. However, in practice, such a material is effectively electrically insulating only if the thickness of the layer is important (thickness of about one micrometer).
• the second track is identical to that of the embodiments of Figures 2j to 2m.
• the non-wetting layer 4 is not partially wetting since it does not comprise the openings 5.
• These variant embodiments are therefore derived respectively from the variants of FIGS. 2k and 21, with the difference above (layer 4 completely non-wetting, while in the variants of Figures 2k and 21, it is partially wetting).
• the alternative embodiment of FIG. 2r shows the mode of displacement of FIGS.
• this variant embodiment does not require an insulating dielectric layer between the interdigital electrodes 2 and the non-wetting layer 4 in the case where this non-wetting layer 4 is itself electrically insulating, this is particularly the case for a hydrophobic layer made of a material such as a tetrafluoroethylene polymer.
• such a material is effectively electrically insulating only if the thickness of the layer is important (thickness of about one micrometer). Also, in the cases of Figure 2r where the thickness of the non-wetting layer 4 is not sufficient, it can be inserted between the interdigital electrode layer 2 and the non-wetting layer 4 an insulating dielectric layer of the type of the layer 3 of the other figures.
• Figure 3 schematically shows the displacement of a drop on a track of the device according to an alternative embodiment.
• This figure is broken down into two parts.
• the representation of the device is a representation in top view and partial in that it does not show the non-wetting layer or partially wetting or insulating dielectric layer, located between the drop 15 and the electrodes 1, 2, 3 and 4.
• the lower part shows the representation of the device in the lower part.
• the representation of the device is a representation in section from the side, in the direction of movement of the drop.
• the device is of the type of that of Figure 2a, that is to say with a single track.
• the following explanations concerning the displacement of the drop are applicable more generally to the cases of FIGS. 2a, 2e, 2m and 2r, that is to say a displacement on a track with interdigital electrodes, without counter-electrodes, possibly with a second upper plane.
• the device therefore requires several interdigitated electrodes (1, 2, 3, 4) which rest on an electrically insulating substrate 10, possibly transparent.
• On the layer of interdigitated electrodes there is an insulating dielectric layer 11 and a non-wetting layer 12.
• This non-wetting layer 12 may be partially wetting according to the configuration in which one is located (see Figure 2 concerned), which does not modify not the following explanations about moving.
• the drop 15 is initially on the electrode 2 (step A). By creating a potential difference between the electrode 3 and the electrodes 1, 2 and 4, the drop moves on the electrode 3 (step B). To move it on the electrode 4, a potential difference is created between the electrode 4 and the electrodes 1, 2 and 3. And so on.
• the representation of the device is a representation in top view and partial in that it does not show either the non-wetting or partially wetting layer or the insulating dielectric layer, located between the drop 15 and the electrodes 1, 2, 3 and 4.
• the representation of the device is a representation in section from the side, in the direction of displacement of the drop.
• the device presented corresponds to a device with a single track and a ground line as a counter-electrode, as previously described in FIG. 2b.
• the following explanations concerning the displacement of a droplet on this device are also applicable to the cases of FIGS. 2c, 2d, 2f, 2g, 2h, 2j, 2k, 2I 1 2o,
• the device comprises a layer of interdigital electrodes (1, 2, 3, 4) which rest on an electrically insulating and possibly transparent substrate. Above this layer of electrodes is an insulating dielectric layer 11. Above this insulating dielectric layer 11 is a non-wetting layer 12. This layer is optionally partially wetting, depending on the configuration in which it is located ( see Figures 2). Above this non-wetting layer 12 (possibly partially wetting), there is a ground electrode or ground line.
• the drop 15 is initially on the electrode 2 (step A). By creating a potential difference between the electrode 3 and the electrodes 1, 2, 4 and the ground electrode, the drop moves on the electrode 3 (step B). To move the drop on the electrode 4, a potential difference is created between the electrode 4 and the electrodes 1, 2, 3 and the ground electrode, and so on.
• FIG. 5 schematically represents the steps of the method of creating an opening in a non-wetting material, which renders it partially wetting, according to the conventional photolithographic technique with surfactant.
• step (a) a layer of non-wetting material 2 is deposited on a substrate 1.
• step (b) a layer of resin 3 containing a surfactant is deposited on the non-wetting layer 2.
• the surfactant allows to increase the wettability of the non-wetting layer with respect to the resin, so the attachment of the resin on this layer.
• step (c) the actual photolithographic step, the layer 3 is subjected to UV radiation.
• the ultraviolet radiation causes a rupture of the macromolecules of the exposed zones, which gives these zones an increased solubility to the developing solvent which will be used in step (d), while the non insolated on the opposite will have polymerized.
• the revelation of the resin is accompanied by an attack of the exposed non-wetting material and thus the appearance of the zones or openings 4 in the non-wetting layer 2 (step (e)).
• This technique is accompanied by the risk of permanently modifying the surface properties of the non-wetting material due to the use of the surfactant in the resin.
• Figure 6 shows schematically the steps of the method of creating openings in a non-wetting material according to the conventional photolithographic technique with plasma.
• This technique differs from the previous one in that it comprises a further step of subjecting the non-wetting layer 2 to plasma-argon radiation (step (b)) prior to deposition of the resin layer. It is this radiation that will modify the surface properties of the non-wetting layer 2, whereas in the previous technique (FIG. 5), it is the presence of the surfactant in the resin that plays this role.
• the following steps ((c), (d), (e), (f)) are respectively the same as steps (b), (c), (d) and (e) of Figure 5.
• the conclusion is the same as for the conventional photolithographic technique with surfactant, namely that there is a risk of permanent modification of the surface properties of the non-wetting layer 2.
• the method of the invention is therefore a method of manufacturing one or more tracks of the device described above, in which the creation of the partially wetting layer firstly comprises a step of creating a mask of photosensitive material by depositing a layer of this material 2 on a substrate 1 (step (a)), photolithography (step (b)), and revealing the photosensitive material (step (c)).
• a negative resin is used as the photosensitive material, that is to say for which the UV radiation causes a polymerization of the insolated zones, resulting in increased solubility of the unexposed zones. in the developer.
• step (b) It is therefore the areas not exposed to step (b) that disappear in step (c), while the areas exposed to step (b) remain present in step (c) and are marked by the Figure 2.
• a negative resin is of course not limited to the invention.
• the considerations of the process of the invention are exactly the same in the case of the use of a positive resin.
• Step (c) is followed by a step (d) of depositing a layer of non-wetting material 3.
• the step (d) of deposition of the non-wetting material 3 is followed by a first annealing step.
• a first annealing step Depending on the material chosen (tetrafluoroethylene polymer for example), it is possible to anneal at 50 ° C. for 5 minutes.
• this annealing is followed by another complementary annealing. This other annealing can then be carried out at a temperature of 110 ° C. for 5 minutes also.
• step (e) In the particular case of a hydrophobic material such as a tetrafluoroethylene polymer, at this stage, very little solvent remains in the material. But it will take a second annealing step after dissolution of the resin mask 2 (step (e) .In fact, at the annealing temperatures of the hydrophobic material, the resin polymerizes which makes it difficult to remove.This may have the consequence of leaving traces of resin on the substrate.These traces may be difficult or impossible to remove during the next step of dissolution, which may to modify the surface properties of the partially wetting layer (partially hydrophilic in the case of wettability with respect to water): the openings may not be perfectly non-wetting (or hydrophobic for non-wettability with respect to water) and unopened areas may not be perfectly non-wetting (hydrophobic). Therefore, before proceeding to this second annealing step, we will first dissolve the resin for example in acetone, for example for 30 to 40 seconds. Preferably, but not necessarily, this dissolution
• the second annealing step is carried out, for example (depending on the material chosen) at 170 ° C. for 5 minutes, which has the effect of completely removing the solvent that may be present in the hydrophobic material.
• another complementary annealing is carried out, for example at 330 ° C. for 15 min.
• the method of the invention advantageously makes it possible to create a partially wetting layer in a non-wetting material.
• This result is achieved by creating openings in the non-wetting material, which become wetting areas, adapted to chemical or biochemical functionalization.
• the unopened areas remain perfectly non-wetting and thus retain their high nonwetting properties necessary for the transport of drops.
• the fact that the layer of non-wetting material is deposited in the last stage of the process unlike the state of the art, makes it possible not to subject this surface treatment material (technique using a surfactant, or using a plasma-argon).
• the device of the invention therefore comprises at least one layer made partially wetting by creating wetting openings in a non-wetting layer, as explained above. These areas wetting agents will be able to be activated and chemically functionalized (FIG. 8) and then react with the manipulated drop (FIG. 9). We will therefore use the principle of displacement of the drop as explained above to activate the areas not yet functionalized with a drop containing an agent for functionalization.
• FIG. 8 (representation mode identical to that of the upper part of FIGS. 3 and 4 is seen in top view and in partial view, that is to say without the respectively insulating and non-wetting dielectric layers between interdigitated electrodes and the drop) that a drop containing an agent allowing the functionalization 15 starting from the electrode 1 moves on the electrode 2, above a functionalizable zone 5 and then arrives on the electrode 3 after having activated and chemically functionalized zone 5.
• FIG. 9 (representation mode identical to that of the upper part of FIGS. 3 and 4, in top view and partial view, that is to say without the respectively insulating and non-wetting dielectric layers between the interdigital electrodes and the drop), we see how a drop 15 moving on the track is first on the electrode 1 and then passes on the electrode 2 above which is the functionalized zone 5, and arrives, modified, on the electrode 3 after reaction with the functionalized zone.
• FIG 10 shows schematically an alternative embodiment of the system according to the invention.
• the system comprises one or more means 1 for preparing the liquid sample to be analyzed, one or more drop-handling devices 2 according to the invention and as explained above, and one or more means 3 for analyzing the output.
• the means 1 of preparation may comprise for example one or more tanks or loading docks.
• the analysis means 3 may be, for example, a mass spectrometer, a fluorescence detector or a UV emission detector.
• the device 2 according to the invention at the heart of this system, is coupled upstream with the means 1 of preparation, and downstream with the means 3 or analysis.
• the system according to the invention can thus be optionally integrated in a microsystem that itself integrates one or more laboratory operations usually performed manually. Such a system is called micro-laboratory.
• the device of the invention comprising a substrate of Pyrex ®, conductive interdigitated electrodes of nickel of a thickness of one hundred nanometers, a layer about one micrometer of resin SU8 deposited by centrifugation, insulating dielectric layer. Finally, the device comprises a hydrophobic layer of tetrafluoroethylene polymer, also deposited by centrifugation, on the previously mentioned resin layer.
• Example of an Affinity Reactor The zones not covered by the hydrophobic layer will undergo a surface treatment intended to transform them into a reactive surface, for example a grafted-NH 2 support Streptavidin.
• a drop of liquid containing proteins for example, and moving in the path of electrodes on a functionalized zone will see its molecules of interest (certain proteins such as biotin for example). ) having an affinity for previously grafted surfaces during functionalization, attach to these surfaces.
• the drop continues its way into the device.
• a specific mixture for example a denaturing buffer mixture
• a drop of liquid moving in the electrode path is immobilized on a functionalized zone, and certain molecules of interest (proteins for example) will react with the grafted surfaces.
• the result of such a reaction will be to cut the molecules (for example peptides obtained by tryptic digestion). Thereafter, gout continues its way into the device.
• Such a device therefore makes it possible, for example, to analyze long chains of molecules by preliminary cutting by means of specific enzymes, for analysis by mass spectrometry.
• the device, the method, and the system of the invention therefore make it possible to produce the basic elements of a microsystem intended to move microdrops from one functionalized zone to another, in an architecture that is perfectly suited to upstream or downstream integration with other complementary functions.
• tetrafluoroethylene polymer material for the non-wetting or partially wetting layer is not limiting of the invention.
• a tetrafluoroethylene polymer is a suitable choice in that it is effectively non-wetting, especially, but not only, with respect to water, therefore hydrophobic. More generally, we will always focus on a non-wetting material, which is biocompatible (does not adsorb material transported, does not mix with the transported material, does not cause chemical reactions, does not release material). It must be neutral with regard to the preceding explanations, and also to present a homogeneity of its properties on the surface.
• the choice of silicon or Pyrex ® for the substrate is of course not limiting of the invention. This is also the case of the choice of a positive or negative resin in the context of the manufacturing process of the device of the invention. It will also be noted, again in the context of the manufacturing process of the device of the invention, that the temperatures and times of the annealing steps of the process are not limiting of the invention, and are essentially a function of the nonwetting material chosen. Also, the use of acetone for dissolution and an alcohol for rinsing is not limiting of the invention. Any other product suitable for dissolution and rinsing may be used.
• the examples of displacement in a given direction are not limiting of the invention.
• the displacement possibilities depend essentially on the geometrical arrangement of the electrodes.
• An array of electrodes makes it possible to obtain a displacement of matrix type.
• the shape of the electrodes in the examples of this description is of course not limiting of the invention. Any other form allowing the interdigitation of the electrodes is suitable.

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