WO2002092228A2 - Procede et dispositif de distribution de gouttelettes - Google Patents

Procede et dispositif de distribution de gouttelettes Download PDF

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Publication number
WO2002092228A2
WO2002092228A2 PCT/IE2002/000061 IE0200061W WO02092228A2 WO 2002092228 A2 WO2002092228 A2 WO 2002092228A2 IE 0200061 W IE0200061 W IE 0200061W WO 02092228 A2 WO02092228 A2 WO 02092228A2
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WO
WIPO (PCT)
Prior art keywords
dispensing assembly
dispensing
sample liquid
nozzle
assembly
Prior art date
Application number
PCT/IE2002/000061
Other languages
English (en)
Other versions
WO2002092228A3 (fr
Inventor
Igor Shvets
Sergei Makarov
Alexander Shvets
Jurgen Osing
Original Assignee
Allegro Research Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/927,355 external-priority patent/US20020168297A1/en
Application filed by Allegro Research Limited filed Critical Allegro Research Limited
Priority to EP02727994A priority Critical patent/EP1385629A2/fr
Publication of WO2002092228A2 publication Critical patent/WO2002092228A2/fr
Publication of WO2002092228A3 publication Critical patent/WO2002092228A3/fr

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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
    • B01L3/02—Burettes; Pipettes
    • B01L3/0241—Drop counters; Drop formers
    • B01L3/0268—Drop counters; Drop formers using pulse dispensing or spraying, eg. inkjet type, piezo actuated ejection of droplets from capillaries
    • 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
    • B01L3/02—Burettes; Pipettes
    • B01L3/021—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
    • 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
    • B01L2400/0475—Moving fluids with specific forces or mechanical means specific mechanical means and fluid pressure
    • B01L2400/0481—Moving fluids with specific forces or mechanical means specific mechanical means and fluid pressure squeezing of channels or chambers

Definitions

  • the present invention relates to a dispensing assembly for sample liquid droplets of less than 5 ⁇ l in volume of the type containing a system liquid and a sample liquid separated by a movable interface divider barrier within an assembly bore such as a gas bubble to prevent mixing of system and sample liquids and to divide the assembly bore which is generally of substantially non-expandable material, into a sample liquid containing portion and a system liquid containing portion, a nozzle having a nozzle bore with a nozzle entrance at the proximal end and terminating in a dispensing tip at its distal end and a positive displacement pump for delivery of metered quantities of system liquid through the assembly to deliver sample liquid through the nozzle bore.
  • the present invention is for use in fields such as drug development, pharmaceutical, medical diagnostics, biotechnology, analytical chemistry and others. It is particularly directed to High Throughput Screening (HTS), Polymerase Chain Reaction (PCR), combinatorial chemistry, microarraying, proteomics and other similar tasks.
  • HTS High Throughput Screening
  • PCR Polymerase Chain Reaction
  • combinatorial chemistry microarraying, proteomics and other similar tasks.
  • the typical application for such a liquid handling system is in dispensing of small volumes of liquids, e.g. 5 microlitres and smaller and in particular volumes around 1 microlitre and smaller.
  • the invention is also directed to aspiration of liquids from sample wells so that the liquids can be transferred between the wells.
  • the invention relates also to microarray technology, a recent advance in the field of high throughput screening and genomics.
  • Microarray technology is being used for applications such as DNA and protein arrays: in this technology the arrays are created on glass or polymer slides.
  • the invention can also be used for simultaneous aspiration and dispensing of a multiplicity of liquids. Such a simultaneous aspiration and dispensing can be required for rapid filling of well plates or plates containing blocks of analytical devices for parallel processing of a range of liquids.
  • the well plates filled with a range of liquids can in turn be coupled to a variety of analytical devices such as electrophoresis analyzers, chromatographers, mass spectrometers and others. Many of these areas of application require routine dispensing of consistent droplets of liquids of submicrolitre volume, in some cases down to only a few nanolitres in volume.
  • the present invention is also applicable to the field of medical, diagnostics e.g. for applications such as single nucleotide polymorphism or others.
  • a dispensing system for ink jet applications is to deliver droplets of a fixed volume with a high repetition rate.
  • the separation between individual nozzles should be as small as possible so that many nozzles can be accommodated on a single printing cartridge.
  • the task is simplified by the fact that the mechanical properties of the ink dispensed are well-defined and consistent. Also in most cases the device used in the ink jet applications does not need to aspire the liquid through the nozzle to refill the dispenser.
  • HTS High Throughput Screening
  • the system should be capable of handling a variety of liquids with different mechanical properties e.g. viscosity. Usually these systems should also be capable of aspiring liquids through the nozzle from a well or other source. On the other hand there is not such a demanding requirement for the high repetition rate of droplets as in ink jet applications.
  • Another requirement in the HTS applications is that cross contamination, between different wells served by the same dispensing device should be avoided as much as possible.
  • the most common method of liquid handling for the HTS applications is based on a positive displacement pump such as described in US Patent Specification No. US 5,744,099 (Chase et al).
  • the pump consists of a syringe with a plunger driven by a motor, usually a stepper or servo-motor.
  • the syringe is usually connected to a nozzle of the liquid handling system by means of a flexible polymer tubing.
  • the nozzle is typically attached to an arm of a robotic system that carries it between different wells for aspiring and dispensing the liquids.
  • the syringe is filled with a system liquid such as water.
  • the system liquid continuously extends through the flexible tubing down towards the dispenser.
  • the sample liquid that needs to be dispensed fills up into the dispenser from the tip. In order to avoid mixing of the system liquid and the sample liquid and therefore cross-contamination, an air bubble or bubble of another gas is usually left between them.
  • the plunger of the syringe is displaced. Suppose this displacement expels the volume ⁇ V of the system liquid from the syringe.
  • the front end of the system liquid filling the nozzle is displaced along with it.
  • the system liquid is virtually incompressible. If the inner volume within the flexible tubing remains unchanged, then the volume ⁇ V displaced from the syringe equals the volume displaced by the moving front of the system liquid in the nozzle.
  • the volume of the air bubble is small relative to the drop size, it is possible to ignore the variations of the bubble's volume as the plunger of the syringe moves.
  • the rear end of the sample liquid is displaced by the same volume ⁇ V in the nozzle, and therefore the volume ejected from the tip is the same ⁇ V.
  • the pump works sufficiently accurately if the volume ⁇ V is much greater than the volume of the air bubble.
  • the volume of the air bubble changes as the plunger of the syringe moves. Indeed in order to eject a droplet from the tip, the pressure in the tubing should exceed the atmospheric pressure by an amount determined by the surface tension acting on the droplet before it detaches from the nozzle. This is discussed in more detail below. Therefore, at the moment of ejection the pressure in the tubing increases and after the ejection, it decreases. As common gasses are compressible, the volume of the air or gas bubble changes during the ejection of the droplet and this reduces the accuracy of the system. The smaller the volume of the air bubble, the smaller is the expected error. In other words the accuracy is determined significantly by the ratio of the volumes of the air bubble and the sample liquid drop to be dispensed.
  • U.S. Patent Specification No. 5741554 (Tisone) describes another method of dispensing submicrolitre volumes of liquids for biomedical application and in particular for depositing bodily fluids and reagents on diagnostic test strips.
  • This method combines a positive displacement pump, namely, a syringe pump filled with a liquid to be dispensed, connected to a tubing terminating in a solenoid valve located close to an ejection nozzle.
  • the pump is driven at constant speed.
  • the solenoid valve is actuated with a defined repetition rate which rate, together with the flow rate of the pump determines the size of each droplet.
  • This method is suitable for dispensing of large number of identical droplets.
  • a charged volume of liquid at the tip of the capillary is repelled from the rest of the capillary by Coulomb interaction as they are both charged with the like charge. This forms a flow of charged particles and ions in the shape of a cone with the apex at the tip of the capillary.
  • a typical electrospray application is described in US Patent Specification No. 5115131 (Jorgenson et al).
  • US Pat. No 4,302,166 (Fulwyler et al) teaches how to handle uniform particles each containing a core of one liquid and a solidified sheath. In this latter invention, the electric field is applied in a similar way to keep the particles away from each other until the sheath of the particles has solidified. In this invention the particles are formed from a jet by applying a periodic disturbance to the jet.
  • US Pat. No 4,956,128 (Martin Hommel et al) teaches how to dispense uniform droplets and convert these into microcapsules. A syringe pump supplies the fluid into a capillary. A series of high voltage pulses is applied to the capillary.
  • the size of the droplets is determined by the supply of fluid through the capillary and the repetition rate of the high voltage pulses.
  • the specification does not discuss generation of a single droplet on demand.
  • the sample liquid fills up all the volume in the capillary (dispenser), the syringe and the tubing joining the two.
  • US Pat. No 5,639,467 (Dorian et al) teaches a method of coating of substrates with a uniform layer of biological material.
  • a droplet generator is employed which consists of a pressurised container connected to a capillary.
  • a high constant voltage is applied between the capillary and a receiving gelling solution.
  • liquid handling system can dispense liquids containing suspensions of hard particles called beads.
  • Typical beads have the size of some 10 to 100 micron although beads with sizes outside this range can also be used. Some of them are ceramics-based and others are made of ferromagnetic materials, e.g. magnetic particles such as sold under the Trade Mark KING FISHER by Thermolabsystems Oy, Helsinki, Finland. Dispensing liquids with beads in the low microlitre volume is a highly challenging task. In addition to all the complications described in detail above, dispensing beads using a solenoid valve can block the seat of the valve.
  • Dispensing the beads using dispensers based on piezoelectric actuators as used in ink jet printing is also complicated.
  • the beads present inhomogeneities with volume comparable with the volume of a drop produced by many such dispensers.
  • Dispensing magnetic beads presents additional difficulties for the solenoid valve-based dispensers. The reason is that the magnetic beads can aggregate in areas of strong gradient of magnetic field inside the valve. Thus the droplets of liquid dispensed are depleted of magnetic beads. The valve itself can malfunction as it accumulates a significant quantity of magnetic material inside.
  • the most common method of handling reagents used in HTS and similar applications is based on a positive displacement pump and a gas bubble.
  • the problem is that when dispensing volumes of reagents around 1 microlitre or smaller the variation in the volume of the bubble during the dispensation compromises the accuracy.
  • the droplet attachment to the tip of the dispenser by surface tension also causes a problem when dispensing submicrolitre droplets. It has been found difficult to eject small droplets of precisely required volume using this method.
  • the tip of the dispenser should be brought closer to the bottom of the well. However, as the distance between the tip and the bottom of the well decreases, the chances of cross contamination increase.
  • US Patent No. 5,559,339 (Domanik) teaches a method for verifying a dispensing of a liquid from a dispenser.
  • the method is based on coupling of electromagnetic radiation that is usually light from a source, to a receiver.
  • the mechanism of such an obstruction is absorption of electromagnetic radiation by the droplet.
  • the disadvantage of this method is that the smaller the size of the droplet, the smaller is the absorption in it. Almost certainly the method will not work for fluids that do not absorb the radiation.
  • the methods disclosed in this specification are inappropriate. Further the specification acknowledges that it will only operate satisfactorily with major droplets.
  • Another objective is to provide an assembly where the quantity of the liquid dispensed can be freely selected by the operator and accurately controlled by the dispensing system.
  • the system should be capable of dispensing a drop of one size followed by a drop of a widely differing size, for example, a 10 nl drop followed by a 500 nl one. This is in contrast to for example ink jet printing where the volume of one dispensation is fixed, and dispensations are only possible in multiples of this quantity.
  • Another objective is to provide a dispensing assembly where cross contamination between different liquids handled by the same dispenser is reduced.
  • Yet another objective of the invention is to provide a liquid handling device and method in which the dispensing assembly or dispenser does not carry an uncontrolled droplet of liquid attached to its tip during the aspiration.
  • the purpose is to reduce the wastage of valuable liquids and improve the accuracy of the very first dispensation after the aspiration.
  • Another objective is to reduce the priming volume of the dispensing assembly or dispenser.
  • the priming volume is understood to be the volume of liquid that must be placed inside the dispenser, e.g. aspirated by the dispenser before it can function properly and deliver the dispensations accurately.
  • the invention is also directed towards providing a method where the liquid can be dispensed on demand, i.e. one quantity can be dispensed at a required time as opposed to a series of dispensations with set periodic time intervals between them.
  • the dispensing assembly should also allow for dispensation of doses with regular intervals between subsequent dispensations, for example, printing with reagents.
  • Another objective of the present invention is to provide a device suitable for dispensing a liquid to a sample well and also for aspiring a liquid from the sample well.
  • the device should be able to control accurately the amount of the liquid aspired into the nozzle of the dispenser from a supply well.
  • Another objective is to provide a low cost front end of the dispensing assembly that could be disposed of when it becomes contaminated namely the part which comes in direct contact with the reagents dispensed.
  • Another objective is to provide a method for handling liquids in a robotic system for high throughput screening, proteomics or microarraying that would be suitable for accurate dispensing and aspiring volumes smaller than the ones obtainable with other mainstream technologies.
  • Yet another objective is to provide means of more accurate delivery of a droplet of liquid reagent to a correct target well on a substrate and also to improve the accuracy of delivery of the droplet to a correct location in a well forming part of a receiving substrate.
  • Yet another objective is to provide means for directing doses of liquids into different wells of a sample well plate and means of controlling the delivery address of the dose on the sample well plate to speed up the liquid handling procedure.
  • Another objective is to provide means for dispensing of small droplets of suspensions of particles including magnetic particles such as magnetic beads.
  • Yet another objective of the invention is to reduce “splashing" as the droplet arrives at the well.
  • Another objective of the invention is to provide validation of the droplet dispensation, namely, whether dispensed or not. It is additionally an objective to measure the volume of the droplet dispensed.
  • Yet another objective is to provide means for simultaneous aspiration and simultaneous dispensation of a range of different sample liquids without cross- contamination thus enabling a multi-channel dispenser.
  • a dispensing assembly for sample liquid droplets of less than 5 ⁇ l in volume of the type containing a system liquid and a sample liquid separated by a movable interface divider barrier such as a gas bubble within an assembly bore to prevent mixing of system and sample liquids and to divide the assembly bore, which is of generally substantially non-expandable material, into a sample liquid containing portion and a system liquid containing portion, a nozzle having a nozzle bore with a nozzle entrance at its proximal end and terminating in a dispensing tip at its distal end and a positive displacement pump for delivery of metered quantities of system liquid through the assembly to deliver sample liquid through the nozzle bore
  • the divider barrier comprises a fixed divider, at least portion of which is of an elastomeric substantially incompressible material.
  • the invention is based on the commonly overlooked fact that many elastomers, although being soft and having low Young's modulus, are still virtually incompressible.
  • the use of a divider barrier according to the present invention overcomes the problems in using gas bubbles and the like.
  • the dispensing assembly comprises a plurality of nozzles.
  • the advantage of this is considerable as there are many situations where it is necessary to dispense 48 or 96 or even more droplets of a sample liquid onto a substrate. If a multi nozzle dispensing head can be used, this is particularly advantageous.
  • the present invention has been found to be particularly adapted to this use.
  • a dispenser having a main bore, on one end of which dispenser forms a nozzle mounting part and the other end of which forms an inner part connected to the positive displacement pump and in which the divider barrier is mounted in the main bore dividing the main bore into a system liquid reservoir forming part of the system liquid containing portion and a sample liquid reservoir forming substantially all of the sample liquid containing portion.
  • the dispenser is a two part body comprising:-
  • the advantage of this is that one can now keep the part of the dispensing assembly, carrying the system liquid, separate from the sample liquid containing part of it. Thus, one can remove the sample liquid containing part, totally sterilize it or simply dispose of it, without having to do anything to the main bulk of the dispensing assembly.
  • the nozzle mounting part, divider barrier and nozzle form the -one sealed sub-assembly.
  • the sub-assembly may be releasably connected to the inner part.
  • the dimensions of the divider barrier and the main bore are configured such as to allow the divider barrier fit closely in the sample liquid reservoir and across and against the nozzle entrance under the influence of the system liquid.
  • the divider barrier comprises at least a pair of closely contacting membranes, at least one membrane secured to the inner part and at least one other membrane to the nozzle mounting part.
  • the membranes have different elastomeric properties.
  • the divider barrier is formed from a separate sample liquid container mounted in the dispenser and connected directly across the nozzle entrance, the sample liquid container forming the sample liquid reservoir.
  • the sample liquid container may be in the form of an expandable bag of an elastomeric material having an apertured neck connected to the nozzle entrance.
  • the divider barrier additionally separates portion of the main bore adjacent each nozzle entrance to form separate sample liquid reservoirs divided from the one system liquid reservoir.
  • the divider barrier may be formed from separate sample liquid containers, each mounted in the dispenser body and across one nozzle entrance.
  • the liquid container may be an expandable bag of an elastomeric material having an apertured neck connected to the nozzle entrance.
  • the divider barrier may comprise the one sheet of material having a plurality of spaced-apart bell shaped depressions in the form of flexible elastomer containers with the flat portions of the sheet clamped between the inner part and the nozzle mounting part, each container lying above a nozzle entrance.
  • the elastomeric material of the divider barrier is pre-stretched.
  • a dispensing assembly comprising:-
  • a controller having means to actuate the generator to cause a wave in the sample liquid as the positive displacement pump completes delivery of the sample liquid to the dispensing tip.
  • the compression wave generator may comprise a piezoactuator for causing compression of portion of the assembly carrying the system liquid, which piezoactuator may be mounted on the nozzle for causing a compression wave in the sample liquid.
  • the compression wave generator is a magnetostrictive actuator for causing compression of portion of the assembly carrying the system liquid which again may be mounted on the nozzle to cause a compression in the sample liquid.
  • the compression wave generator When the compression wave generator is a magnetostatic actuator, it may include a magnetic core and magnetic coils coupled together for causing a sudden compression of portion of the assembly carrying the system liquid.
  • the compression wave generator may also comprise a mechanical actuator for delivering a sharp blow to the dispenser body.
  • the positive displacement pump comprises an assembly of at least two pumps installed in parallel, one pump having a working stroke displacing a volume at least about ten times larger than that of the other pump.
  • a system liquid level detector is provided.
  • the invention provides a dispensing assembly comprising:-
  • a high voltage generating means connected to at least one of the electrodes to provide an electrostatic field therebetween.
  • the separate receiving electrode may be positioned below the dispensing tip.
  • the receiving electrode includes a hole for the passage of a droplet therethrough.
  • a droplet receiving substrate is mounted between the receiving.electrode and the dispensing tip.
  • the receiving electrode is mounted on synchronous indexing means.
  • the high voltage generating means includes control means for activating the receiving electrodes separately.
  • the receiving electrodes are mounted on an indexing table.
  • the invention provides a method of operating a dispensing assembly in which the steps are performed of:-
  • the dispensing assembly is used to aspirate sample liquid from a sample store
  • the dispensing assembly is operated to detach any droplet adhering to the dispensing tip after aspiration;
  • Fig. 1 is a diagrammatic view of a positive displacement pump arrangement of the prior art
  • Figs. 2 is a diagrammatic diagrammatic view of a dispensing assembly according to the invention
  • Figs. 3 and 4 are diagrammatic views of other dispensing assemblies
  • Figs. 5, 6 and 7 illustrate a particular embodiment of dispenser for three different positions in use in a dispensing assembly
  • Figs. 8, 9 and 10 illustrate diagrammatically another alternative construction of dispenser.
  • Fig. 11 illustrates another construction of dispenser.
  • Fig. 12 illustrates an alternative construction of dispensing assembly
  • Fig. 13 illustrates another construction of dispensing assembly
  • Figs. 14 illustrates a compression wave generator utilising piezo actuators
  • Fig. 15 is a circuit of a voltage pulse generator
  • Fig. 16 is another compression wave generator
  • Figs. 17 is a part sectional view of a compression wave generator
  • Fig. 18 is a part sectional view of another embodiment of a compression wave generator
  • Fig. 19 is a part sectional view of a compression wave generator utilising a magnetic coil actuator
  • Fig. 20 is a view of another dispenser
  • Fig. 21 is a diagrammatic view of a dispenser of the invention
  • Fig. 22 is a diagrammatic view of a dispenser of the invention
  • Fig. 23 is a diagrammatic view of a dispenser of the invention.
  • Fig. 24 is a diagrammatic view of a dispensing assembly of the invention.
  • Fig. 25 is a diagrammatic view of a dispensing assembly of the invention.
  • Fig. 26 is a diagrammatic view of a dispensing assembly of the invention.
  • Fig. 27 is a diagrammatic view of a dispenser of the invention.
  • Fig. 28 is a diagrammatic view of a dispenser of the invention.
  • Fig. 29 is a diagrammatic view of part of a dispensing assembly with droplet navigation
  • Fig. 30 is a diagrammatic view of part of a dispensing assembly with droplet navigation
  • Fig. 31 is a diagrammatic view of part of a dispensing assembly with droplet navigation
  • Fig. 32 is a diagrammatic view of part of a dispensing assembly with droplet detection
  • Fig. 33 is a diagrammatic view of a dispensing assembly for multi-droplet dispensing
  • Fig. 34 is a diagrammatic view of a dispensing assembly for multi-droplet dispensing
  • Fig. 35 illustrates the dispenser of another multi-droplet dispensing assembly
  • Fig. 36 is a diagrammatic view of yet another dispensing assembly.
  • a motor (1) driving a piston (2) of a positive displacement pump (3) containing a system liquid, such as water (4) connected by flexible tubing (5) to a robotic arm (6) carrying a nozzle (7) having a tip (8) into which the tubing (5) projects.
  • a sample liquid (9) is contained in the nozzle (7) adjacent to the tip (8) and separated from the water (4) by a gas bubble (10) .
  • the motor (1 ) which is usually a stepper or servo motor will each time move the piston (2) to dispense the sample liquid.
  • the invention is based on the fact that accurate syringe pumps are capable of metering volumes of liquids well below one microlitre.
  • the smallest volume that can be metered by a syringe pump depends on the overall volume of the syringe and precision of the mechanical system driving the plunger of the syringe.
  • a syringe pump having even a relatively low accuracy of the mechanical system is usually capable of ejecting the contents of the syringe in at least 1000 steps or more. Therefore, if e.g. a small syringe with the volume of some 10 microlitre is used with the pump, then the smallest volume that can be metered by the pump is 10 nl.
  • the volume of 10 nl is some two orders of magnitude smaller than the dispensing limit of current liquid handling systems using syringe pumps. The reason why the accuracy of the syringe pumps is not fully used at present, has been detailed already in this specification.
  • the present invention uses the potential accuracy of a syringe pump to the full extent.
  • the invention is based on the commonly overlooked fact that many elastomers although being soft and having low Young's modulus, are still virtually incompressible. For example, during a uniaxial strain deformation, as the length of the elastomer increases, its width and breadth decrease keeping its volume almost unchanged. The ratio of the fractional width change to the fractional length change is given by the Poisson ratio. For many elastomers, it is almost equal to 0.5. Those familiar with mechanics of deformations will appreciate that for materials with the Poisson ratio equal to 0.5, the volume change of the material during such deformations is very small.
  • Bulk modulus is defined as ⁇ P/( ⁇ V V) where ⁇ V is the volume change of a piece of material having volume V in response to the pressure change ⁇ P applied to it.
  • High value of the bulk modulus means that the material is almost incompressible during isotropic deformation caused by homogeneous pressure.
  • the dispensing assembly comprises a positive displacement pump connected to a dispenser.
  • the concept of the dispenser is as follows. There are two reservoirs: the system liquid reservoir and the sample liquid reservoir. They are separated by means of a divider barrier formed by a flexible membrane or an expandable bag.
  • the syringe pump communicates with the system liquid reservoir. All the other walls of the reservoirs are preferably rigid.
  • the sample volume reservoir communicates with a nozzle forming part of the dispenser.
  • the system liquid reservoir is preferably entirely filled with a liquid such as water. As most liquids are practically uncompressible, the volume of the system liquid reservoir remains constant irrespective of the position of the plunger of the syringe pump.
  • the volume of the material of the membrane or the expandable bag positioned between the system and sample reservoirs is also practically constant. Therefore, by moving the plunger and displacing the membrane, we can expel a well-defined volume of sample liquid from the nozzle that is exactly equal to the volume displaced by the syringe pump. This sample liquid could be separated from the.- nozzle to form a droplet if the expelled volume is large enough or alternatively it will be suspended at the tip of the nozzle. If suspended, the droplet is detached by electrostatic drop off or by sending a compression wave through the sample liquid or by directly contacting the substrate by the nozzle.
  • the invention could be split into four constituent features : 1. Means for control of the volume of the sample liquid expelled from the nozzle,
  • the dispensing assembly 1 comprises a dispenser 2 having an inner part 3 and a nozzle mounting part 4.
  • a divider barrier 5 formed by a flexible elastomer membrane clamped between the inner part 3 and nozzle mounting part 4 of the dispenser by means of the clamping means 8, in this embodiment, spring clips.
  • the elastomer membrane forming the divider barrier 5 hermetically divides a main bore for the dispenser 2 into two bore sections, namely, a system liquid reservoir 6 and a sample liquid reservoir 7.
  • the system liquid reservoir 6 forms part of a system liquid containing portion and the sample liquid reservoir 7, all of a sample liquid containing portion of the dispensing assembly 1.
  • the system liquid reservoir 6 communicates with a syringe pump 10 by means of a nonexpendable tubing 11.
  • the syringe pump 10 is controlled by a syringe pump motor 12 that is in turn controlled by a controller 13.
  • the nozzle 15 has a nozzle bore 17 with a nozzle entrance 18 at its proximal end, communicating with the sample liquid reservoir 7 of the main bore.
  • the nozzle 15 is inserted in the dispenser 2 preferably in such a way that it does not protrude significantly inside the sample liquid reservoir 7.
  • the inner surface of the sample liquid reservoir 7 is preferably smooth.
  • a droplet is identified by the reference numeral 28.
  • the means comprises a conducting plate forming a drop-off or receiving electrode 19 positioned underneath a substrate 20.
  • An electrode 25 electrically coupled to the dispensing tip 16 in this embodiment mounted in it is connected to a high voltage source 26 also connected to the receiving electrode 19.
  • the high voltage source 26 is also controlled by the controller 13 generates electrostatic field between the dispensing tip 16 and the substrate 20.
  • the substrate 20 could be made of a conducting material and thus form the receiving electrode. In this case the high voltage source 26 could be directly connected to the substrate 20.
  • the flexible membrane is made of a material such as Latex with the thickness of up to 0.5 mm, although membranes with greater thickness can also be used.
  • the nozzle is a stainless steel capillary with the internal diameter of 0.07 to 0.4 mm, although values outside this range can also be used.
  • the system liquid reservoir and sample liquid reservoir have axial symmetry. In the embodiment shown in Fig 2, the axes of the system liquid reservoir and the sample liquid reservoir coincide with the axis of the nozzle, although other embodiments, in which this is not the case, can readily be designed.
  • the walls of the sample liquid reservoir are preferably smooth so that when the membrane is fully extended to expel the sample liquid from the dispenser, it applies tightly to the walls of the dispenser to reduce the dead volume in the dispenser.
  • the smooth inner walls of the sample liquid reservoir also reduce the chances of making a puncture in the membrane.
  • the diameter of the sample liquid reservoir is some 0.4 to 4 mm and its depth is in the range of 0.4 to 4 mm although values outside this range can be used depending on the desired volume of dispensation.
  • the inner part 3 and the nozzle mounting part 4 of the dispenser are formed of a plastics material by injection moulding or another suitable mass production technique. The dispenser 2 then becomes essentially a low-cost, disposable element within the dispensing assembly.
  • the conducting plate 19 can also be used advantageously during the aspiration phase.
  • a droplet of sample liquid may get attached to the tip 16 of the nozzle.
  • This droplet is undesirable for many applications.
  • the volume of this droplet is difficult to control since it depends on the surface tension of the specific sample liquid aspired.
  • This droplet contributes to the wastage of valuable sample liquid and also can have a detrimental effect on the accuracy of the very first dispensation as it can add to the volume of the first dispensation.
  • the dispensing assembly 1 can be used to obviate this problem.
  • a strong electric field is applied at the tip 16 of the dispenser. This field removes any such droplet attached to the tip 16.
  • the field is generated by means of a high voltage applied between the receiving electrode 19 and the nozzle 15. It is proposed that in a typical application, a robotic arm as in the prior art will remove the nozzle of the dispenser from the sample well plate by only some 1 to 5 mm in a vertical direction and then the voltage is applied to the receiving electrode and the nozzle to transfer sample liquid attached to the nozzle 15 back exactly into the same well from which it has been aspired. This avoids unnecessary wastage of the sample liquid .
  • FIG. 3 there is illustrated another dispensing assembly, again identified by the reference numeral 1 where parts similar to those described in Fig. 2 are identified with the same numerals.
  • the only difference is that there is a pressure sensor 27 attached to the system liquid reservoir 6 and the controller 13.
  • a pressure sensor such as the 24 PCGFM1 G manufactured by Honeywell Inc. could be used. The readings from the pressure sensor 27 are sent to the controller 13 during the aspiration and dispensation.
  • the readings from the pressure sensor 27 are continuously taken by the controller 13.
  • the reading of pressure Po corresponding to the membrane being fully extended into the sample liquid reservoir 7 could be recorded by the controller 13 using a calibration run of the dispensing assembly 1.
  • the controller 13 stops advancement of the syringe pump's plunger 9 and discontinues expulsion of the system liquid from the pump 10. This would then indicate that the dispenser is empty of the sample liquid.
  • the membrane is stretched straight. It could be beneficial to stop moving the plunger of the syringe at this moment.
  • the pressure range at which the syringe pump should stop moving during the dispensing and aspiration of liquid can be selected depending on the specific configuration of the dispenser. In some instances it may be beneficial to operate the dispensing assembly in such a way that the membrane is continuously extended into the sample liquid reservoir. This is described in detail below with reference to Fig. 33.
  • the substrate also serves as a receiving electrode 19.
  • a further dispensing assembly again identified by the reference numeral 1 , in which parts similar to those of Figs. 2 and 3 are identified by the same numerals.
  • the main difference between the dispensing assemblies 1 is that there are valves 30, 31 and 32 in this embodiment connected to the controller 13, all of which valves can be electrically opened and closed by the controller 13.
  • the valve 30 separates the system liquid reservoir 6 from the syringe pump 10.
  • the valve 31 separates the system liquid reservoir 6 from a system liquid supply 33.
  • the valve 32 separates the system liquid supply 33 from the outside atmosphere.
  • the system liquid supply 33 is a container filled with a system liquid. This could be e.g.
  • a flexible bag preferably with a volume greater than the volume of the system liquid reservoir communicating with the latter.
  • system liquid supply could consist of an additional syringe or another syringe pump filled with system liquid.
  • the process of filling the system liquid reservoir with the system liquid and expelling gas bubbles could be simplified if the system liquid supply indeed comprises a separate syringe pump.
  • the inner part 3 and nozzle part 4 are bonded together with the membrane of the divider barrier 5 bonded in between.
  • the inner surface 34 of the inner part 3 of the dispenser 2 facing the membrane 5 is not flat but convex.
  • Figs. 5 to 7 there is illustrated an alternative construction of dispenser which is substantially identical to the dispenser already described with reference to the previous Figs. 2 to 4 and is thus identified by the same reference numeral 2.
  • the inner part 3 is connected to the nozzle mounting part 4 by clamping screws 35.
  • the nozzle mounting part 4 also incorporates an annular rim 36 for the sealing of the membrane 5 between the parts. It will also be noted that the inner surface 34 of the inner part 3 facing the membrane 5 is concave.
  • Fig 5 shows the dispenser with membrane 5 fully pressed against the inner part 3 of the dispenser 2. This corresponds to the dispenser 2 having aspirated the maximum amount of sample liquid.
  • Fig. 7 shows the dispenser with the membrane fully pressed against the nozzle mounting part 4 of the dispenser. This position corresponds to the sample liquid being fully expelled from the dispenser 2.
  • Fig. 6 corresponds to an intermediate position of the membrane 5. It is important to appreciate that the membrane can move from the position shown in Fig. 5 to the one shown in Fig. 7 in a number of steps.
  • the total volume of the main bore i.e. the aggregate of the system liquid reservoir 6 and the sample liquid reservoir 7 could be of the order of 2 microlitres and could be ejected in e.g. 100 steps making each dispensation equal to 20 nanolitres. It could also be ejected in one step.
  • divider barrier is formed from a separate sample liquid container in the form of an expandable bag 40.
  • the bag 40 has an apertured neck which engages over the nozzle entrance 18.
  • the expandable bag 40 separates the system liquid reservoir 6 from the sample liquid reservoir 7.
  • Fig. 8 shows the expandable bag 40 in an almost fully expanded position.
  • Fig. 10 shows it in the fully compressed position when essentially all the sample liquid is being expelled.
  • Fig. 9 shows the expandable bag in an intermediate position.
  • the only sample liquid remaining in the dispenser shown in Fig. 10 is the liquid in the nozzle 15.
  • the dispenser 2 can aspirate and eject a washing liquid. In this case the sample liquid remaining in the nozzle 15 will be diluted/washed out. If necessary, this procedure can be repeated several times before the dispenser is filled up with a new sample liquid.
  • the expandable bag of an elastomer with a significant range of elasticity. This would allow reducing the dead volume in the dispenser left inside the expandable bag at the end of the dispensation.
  • the inner part 3 and the nozzle mounting part 4 are held together by a suitable bonding agent.
  • Fig. 11 there is illustrated an alternative construction of dispenser, again identified by the reference numeral 2 and parts similar to those described with reference to the previous drawings are identified by the same reference numerals.
  • the divider barrier 15 comprises two closely contacting members, in this case, two contacting sheets or membranes 5a and 5b.
  • the membrane 5a is bonded to the inner part 3 by a suitable adhesive and the membrane 5b is connected again to the nozzle mounting part 4 by adhesive.
  • means for releasably securing the inner part 3 to the nozzle mounting part 4 comprising a pair of clamping plates, namely, an upper clamping plate 41 and a lower clamping plate 42 connected together by springs 43.
  • the sheets 5(a) and 5(b) may have different elastomeric properties.
  • the nozzle mounting part 4 along with the membrane 5b that has been in contact with the sample liquid can be exchanged to avoid cross contamination.
  • the inner part 3 along with the membrane 5b does not come in direct contact with the sample liquid at all.
  • This embodiment makes effectively the dispenser 2 a disposable element and removes the need to wash it when the sample liquid is exchanged.
  • the disposable element is the nozzle mounting part of the dispenser.
  • a dispensing assembly again indicated generally by the reference numeral 1 , substantially similar to the dispensing assembly illustrated in Fig. 4 and thus parts similar to those described with reference to Fig. 4 are identified by the same reference numerals.
  • the receiving electrode identified by the reference numeral 45
  • the receiving electrode 45 is connected to the high voltage source 26.
  • the nozzle 15 is connected to the ground potential. Strong electrostatic field is generated between the dispensing tip 16 of the nozzle 15 and the receiving electrode 45. This field pulls off the droplet 28 from the tip 16 of the nozzle 15.
  • a compression wave generator 50 connected to the controller 13 and to the tubing 11 and hence the system liquid reservoir 6 through further tubing 51.
  • a compression wave generator is a device that can excite a wave in the system liquid and/or sample liquid that reaches the tip of the dispenser.
  • the wave causes the droplet suspended at the tip to detach from the dispenser 2. Therefore, the operation of the dispenser 2 is as follows.
  • the required volume of the sample liquid to form a droplet is expelled from the dispenser 2 by advancing the plunger 9 of the syringe pump 10.
  • the compression wave generator 50 is actuated by the controller 13 and the droplet 28 is separated from the tip 16.
  • the electrostatic drop off does not necessarily need to be used. However, incorporation of the electrostatic receiving electrode can still be advantageous even though the electrostatic field is not used for the droplet detachment.
  • electrostatic drop-off means By using electrostatic drop-off means, it is possible to provide an electrostatic field that would not necessarily be strong enough to cause the droplet to detach from the dispensing tip 16 but would, to a significant extent, compensate for the attraction of the droplet to the dispensing tip 16 caused by the liquid surface tension. As a result, a compression wave of smaller amplitude may be sufficient to separate the droplet from the dispensing tip 16.
  • a piezoactuator indicated generally by the reference numeral 52, which piezoactuator 52 comprises a piezo tube 53 rigidly connected to a pair of flanges 54 and 55.
  • the piezo tube 53 mounts an inner tubular electrode 56 and an outer tubular electrode 57, electrically connected to a voltage pulse generator 58 which is in turn connected to the controller 13, for example, as illustrated in Fig. 13.
  • the tube 51 comprises an expandable section in the form of a bellows 59 connected to the tube 51.
  • the tube 51 is connected rigidly to the flange 54 at 60 and the bellows 59 is connected by a mechanical link 61 to the flange 55.
  • the portion of the tube 51 connected to the flange 54 is of a rigid material, -for example, a thin walled metal tube.
  • the bellows 59 is of the same material.
  • the piezoactuator is based on a piezo tube.
  • the tube could be made of materials such as that of the PZT family. Materials of this family are known to those skilled in the art of piezomaterials. They are manufactured by a number of companies under a range of brand names. For example, Staveley Sensors Inc., 91 Prestige Park Circle, East Hartford, CT 06108, manufactures them under trade names such as EBL2 and EBL3.
  • the thickness of the tube wall is some 0.3 to 0.8 mm. Its length is some 8 to 50 mm and diameter is 3 to 20 mm. Specific compression wave generators with values of wall thickness, length and diameter outside this range can also be readily designed.
  • the tube is usually polarized radially.
  • the voltage pulse generator 56 is capable of generating a voltage pulse with the amplitude of some 100 to 500 V and the duration of 10 microseconds. By applying this pulse to the inner and outer electrodes, one therefore excites a wave in the system liquid.
  • the amplitude of the voltage pulse applied to the inner electrode 56 and the outer electrode 57 one has to be careful not to exceed the maximum allowed value of the electric field that can depolarize the piezo tube 53. This depends mainly on the material of the tube, and its thickness and also some other parameters such as e.g. temperature of the tube. Typical values for the depoling electric field are in the range of 300 to 600 V/mm.
  • the volume expelled from the compression wave generator as a result of the piezo tube 53's static contraction is proportional to the voltage applied to the piezo tube 53 from the voltage pulse generator, length of the piezo tube 53 and cross sectional area of the bellows 59.
  • calculating the volume expelled is more complex.
  • the volume depends on the mechanical dynamic response properties of the compression wave generator and the duration of the pulse. This volume can be very small by comparison with the volume of the droplet to be dispensed and still the compression wave generator could function correctly. Having the timing of the piezo tube 53's contraction short is as important as increasing the amplitude of contraction.
  • a piezo tube 53 with a length of some 10mm typically contacts by up to some 5 micrometers.
  • the cross sectional area of the bellows 59 is some 5 mm 2 , then the volume expelled by the compression wave generator is only up to some 25 nanolitres. This presumes the tubing 11 is unexpandable.
  • the tubing 11 is unexpandable.
  • the tubing 11 will expand to a certain extent and dampen the compression wave.
  • the required amplitude of the compression wave also depends on parameters such as surface tension of the liquid dispensed and diameter of the nozzle 15. In addition it depends on the distance between the compression wave generator and the tip. In general the longer this distance, the more significant is the damping of the compression wave by the time is reaches the tip 16.
  • the voltage generated by the voltage pulse generator 58 is gradually increased launching waves of progressively increasing amplitudes.
  • the duration of the pulse generated by the voltage pulse generator is kept as short as possible. For example, one could generate pulses with the duration of 1 microsecond and the amplitude of 20, 40, 60, 80 and so on Volt.
  • There is a critical voltage required for the droplet separation that depends on a number of parameters of the dispenser as described above.
  • Fig. 15 shows an example of schematics of a circuit of a voltage pulse generator.
  • the circuit can energise the compression wave generator. It can generate voltage pulses with an amplitude of over 200 and a duration of the pulse of some 10 "5 seconds.
  • the circuit is supplied with the control voltage pulse to the input of the amplifier U1. This voltage pulse is transformed and amplified by the circuit and supplied through the resistor R8 to the piezo transducer.
  • Fig. 16 there is illustrated an alternative construction of compression wave generator, again a further form of piezo actuator 65.
  • the same numerals as those of Fig. 14 are used to identify the same parts.
  • the tube 51 is of a rigid material between at least the flanges 54 and 55 to which it is securely connected.
  • the tube 51 is rigidly connected, as before, at 60 to the flange 54 and mounts on its other end, a compression wave membrane 66 of a flexible elastic material such as a thin metal foil which in turn is connected by a bar 67 to the flange 55.
  • the piezo tube 53 is connected to an intermediate tube support 68 in the form of a heavy ring which is in turn connected by a spring 69 to the flange 54.
  • the spring 69 loads the flange 55 against the compression wave membrane 66.
  • the compression wave membrane 66 could be a thin metal foil, with a thickness of some 20 micron or greater bonded to the end of the system liquid tube. To increase the range of elasticity of the membrane, it could be advantageous to increase the diameter of the system liquid tube to over 10 mm. This would clearly require increasing the inner diameter of the piezo tube.
  • Increasing the mass of the piezo tube support 68 can be advantageous as explained below. If the length of the piezo tube 53 is decreased slowly as a result of a slow voltage ramp applied to the tube, this piezo tube's length reduction will be absorbed by extension of the spring's length and therefore will not be fully transferred into the compression wave membrane. However, if the contraction of the piezo tube happens very rapidly caused by a short voltage pulse applied to the piezo tube, the situation in different. In this case, most of the piezo tube's length contraction will be absorbed by the compression wave membrane provided the mass of the piezo tube 53 and the piezo tube support 69 is considerably greater than the mass of the flange 55 and the mechanical link 67. This result is then based on inertia.
  • the inertia can be a major player during extension/contraction of the piezo tube caused by a short voltage pulse. Indeed although the compression of the piezo tube is relatively small and is typically in range of 10 "6 to 10 "5 m for the tube of some 10 mm length, the shortness of the time during which the extension takes place (10 "7 to 10 s sec) results in a significant acceleration in the range 10 4 to 10 9 m/sec 2 . Therefore, by using action of inertia, one can achieve the situation whereby the compression wave membrane is preloaded against the flange 55 by means of a relatively soft spring with significant range of elasticity.
  • the bar 67 is a bar with a diameter of some 1 to 2 mm mechanically coupling the centres of a compression wave membrane 66 and the flange 55.
  • the intermediate tube support 68 has two functions. The first is to facilitate the bonding of the spring 69 to the piezo tube 53 as bonding of the spring material with brittle piezo material can be complicated. The second is that the intermediate tube support 68 increases the mass of the assembly attached to the spring 69 and therefore enables the use of inertia for launching of the compression wave as explained above.
  • FIG. 17 there is illustrated another compression wave generator, in this case, a magnetostrictive actuator, indicated generally by the reference numeral 70.
  • the diameter of the pillars 71 is some 1 to 5 mm and their length is some 10 to 30 mm.
  • Embodiments of compression wave generators with magnetostrictive elements having dimensions outside this range could be also designed.
  • the voltage pulse generator 58 can generate a current pulse and therefore the pulse of magnetic field.
  • the length of the magnetostrictive pillars 71 will change moving the flange 55 and therefore coupling the compression wave into the system liquid through the mechanical link 61.
  • the optional pre-stress spring can help to improve the performance of the magnetostrictive actuator.
  • magnetostrictive element Numerous other designs employing a magnetostrictive element or elements could be readily proposed. For example, one could use a single cylindrical magnetostrictive element in the shape of a cylinder instead of a number of pillars. It is not necessary to use separate magnetic field coil for each of the pillars. One could generate a field around all of the pillars using a single coil.
  • Suitable magnetostrictive materials can be found in handbooks on magnetic materials. For example, materials such as Nickel or certain types of permalloy can be employed. These are specially developed materials with high magnetostriction constants such as, e.g. Tb x Dy y Fe z alloys called Terfenol that could also be employed. These materials-are commonly known to designers of magnetic actuators.
  • magnetostrictive actuators compared to the ones using piezomaterials are that they do not perform as well at high frequencies, e.g. above 100 kHz. On the other hand they can deliver greater amplitude of displacement, e.g. greater amplitude of the compression wave.
  • special materials with low conductivity e.g. Terfenol particles embedded in a non-conducting matrix or special laminated materials.
  • bias magnetic field could be generated by a DC current supplied to the four coils 72.
  • the DC field could be generated by driving current of 1 amp through the coils 72 and the pulse of magnetic field could be created by a current pulse with the amplitude of some 0.5 amp superimposed on it.
  • an electronic circuit of the current pulse generator should be designed in such a way as to be capable of supplying a current pulse against background of the DC current both being fed into the same load. Circuits of this kind can be readily designed by those skilled in the art of electronics. Other solutions for the creation of the DC offset field can be readily proposed.
  • the sign of the compression depends on the direction of the magnetic field with regard to the orientation of the grains in the magnetostrictive material. Therefore, not only the shape of the magnetostrictive pillars matters but also the micrograin structure direction is important. If the extension of the magnetostrictive pillars is achieved instead of desired contraction, then this could be easily corrected e.g. by reversing the sign of the current pulse. For example, pulse with the amplitude of -0.5 amp could be superimposed on the DC current instead of the +0.5 amp pulse. Alternatively, the mechanical link and the coupling to the system liquid tube could be changed to benefit from the extension of the magnetostrictive pillars and not their contraction.
  • FIG. 18 there is illustrated an alternative construction of magnetostrictive actuator, indicated generally by the reference numeral 75. Parts similar to those described with reference to Figs. 16 and 17 are identified by the same reference numerals. Operation of this embodiment of compression wave generator is self-explanatory on the basis on the description related to Figs 16 and 17.
  • a magnetostatic actuator indicated generally by the reference numeral 80. Parts similar to those described with reference to Fig. 18 are identified by the same reference numerals.
  • the flanges 54 and 55 are mounted between two opposed sets of magnetic actuators, indicated generally by the reference numerals 81 and 82.
  • the magnetic actuator 81 comprises two half coils 81a and 81 b connected together by springs 83 and surrounded by two sets of coils 84 and 85.
  • the magnetic actuator 82 also has two sets of coils 86 and 87.
  • the coils 84, 85, 86 and 87 are all connected to the pulse generator 58.
  • the coils 84, 85, 86 and 87 are energized with a magnetic field by means of a current pulse generator 58, there will be attractive force acting between the two parts of the magnetic cores. This force will push the flange 55 towards the compression wave membrane 66 and will excite the compression wave in the system liquid.
  • the coils 84 and 85 will excite magnetic field that is opposite to each other as indicated by arrows. The same applies to the coils 86 and 87. In this way they excite continuous magnetic flux throughout each of the two magnetic cores 81 a, 81 b and 82a, 82b. It may be beneficial to use the core of magnetic material having high magnetic permeability at high frequency.
  • the short current pulse in the coils has high-frequency components in the spectrum. Therefore, to increase the force of attraction of the two parts of magnetic core, it may be advantageous to use a core with high magnetic permeability at high frequency, particularly in the case when the coil can be energised within a very short time. This time is determined primarily by the inductance and resistance of the coil and by the current pulse generator. Suitable materials can be found in numerous product data books. For example, material such as manganese zinc ferrite type 77 or 78 sold by Fair-Rite Products Corp, is a suitable option. Similar soft ferrites are manufactured by a number of other companies.
  • the inner part 3 comprises a bimorph piezo consisting of layers 3a and 3b of piezo material connected to the voltage pulse generator 58.
  • the piezo layers 3a and 3b are polarized in such a.-way that when one of the layers extends, the other one contracts.
  • the central area of the inner part 3 of the dispenser bends 2 towards the membrane 5 as shown in Fig 21. If this is done rapidly as a result of a voltage pulse applied to the piezo bimorph, the compression wave is excited in the dispenser 2.
  • the bending mode of mechanical oscillations usually has a lower resonance frequency than the thickness mode. Therefore, even if the voltage pulse generator sends a very short voltage pulse to the piezo layers, the bimorph may not be able to respond by a rapid deformation if its own resonance frequency is too low. By increasing the thickness of the bimorph or by decreasing its length, one can increase the resonance frequency of the compression waver generator.
  • the shape of the piezo bimorph under the bending deformations can be calculated using the standard formulas for the mechanics of deformations readily available in the literature.
  • the piezo bimorph can consist of the same material PZT as described above.
  • the optimal thickness of the layers depends on the size of the dispenser that is in turn determined by the required volume of the sample liquid reservoir. For a sample liquid reservoir with the diameter of some 5 mm, the thickness of the piezo layers in the range of 0.2 to 0.6 mm was found to be acceptable.
  • the thicker the individual layers of the bimorph the smaller is the bending deformation. Therefore, when thicker layers are used, a voltage pulse of greater amplitude should be applied to the bimorph to excite the wave of the same amplitude.
  • using thicker piezo bimorph has advantage in that the resonance frequency of the bimorph increases making excitation of a faster compression wave possible.
  • a piezoactuator similar to the piezoactuator 52 and thus identified by the same reference numerals, used in the embodiment of Fig. 14, can be mounted on the dispenser and in this embodiment, is coupled with the nozzle 15.
  • the compression wave generator based on a piezo tube is coupled to the nozzle. It can be advantageous to make the nozzle of a capillary with a very thin wall to enable its easier extension/contraction by means of the compression wave generator.
  • the piezo tube 53 is bonded between flanges 54 and 55. The two flanges 54 and 55 are in turn bonded to the nozzle 15.
  • the piezo tube 53 is polarized radially in the same way as in the embodiment of Fig. 14.
  • the length of the tube is some 5 to 30 mm and its inner diameter is some 1 mm or greater.
  • the wall thickness of the tube is some 0.3 to 1 mm. Compression wave generators using tubes with sizes outside this range can also be readily designed.
  • the material of the piezo tube can be identical to the one described in earlier embodiments.
  • FIG. 23 there is illustrated the use of the magnetostrictive actuator such as the magnetostrictive actuator 70, illustrated in Fig. 17 and again identified by the same reference numeral in this drawing, can be used when coupled to the nozzle 15 of the dispenser, again identified by the reference numeral 2. Again, parts similar to those described with reference to Fig. 17 are identified by the same reference numerals.
  • only one coil 95 is used and instead of a plurality of pillars 71 , a cylinder 96 of magnetostrictive material is used which is then bonded between the flanges 54 and 55.
  • the magnetostrictive material is similar to the one used some previous embodiments.
  • the outer diameter of the cylinder 96 could be in the range of some 1 to 5 mm.
  • the length of the cylinder 96 could be in the range of some 10 to 30 mm.
  • the cylinder of the magnetostrictive material is placed inside the coil 95 which again is connected to the current pulse generator 58. In use, a short current pulse in the coil 95 generates the pulse of magnetic field at the cylinder 96 of magnetostrictive material and causes the compression of the cylinder 96. The nozzle 15 is also rapidly compressed thus enabling the separation of the droplet from the tip of the nozzle.
  • a dispensing assembly again indicated generally by the reference numeral 1 , substantially similar to the dispensing assembly illustrated in Fig. 4.
  • additional tubing 97 feeding the tubing 11 to a high-speed valve 98 connected to the controller 13.
  • the high-speed valve is connected to a separate system pressurising means, namely a gas compressor 99 feeding through a line 100, the high-speed valve 98.
  • System liquid and compressed gas is contained in the line 100 forming an interface 101.
  • the compressor 99 is capable of producing positive pressures in the range of up to 10 or 20 bar. Operation of this dispensing assembly is as follows. Suppose, the system liquid continuously fills up the line joining the high-speed valve with the tubing and also the high-speed valve itself. In this case the level of system liquid is above the high-speed valve as shown in Fig. 24. Suppose, the high-speed valve 98 is closed and pressure in the line 100 above the high-speed valve, i.e. in the section of the line joining the high-speed valve with the pressure source, is equal to P e j ec t that is above the atmospheric pressure. Suppose the sample liquid is aspirated into the sample liquid reservoir 7 by the syringe pump 10 as described above.
  • the volume of the sample liquid aspirated is defined by the displacement of the syringe pump 10.
  • the high-speed valve 98 is opened. Pressure in the system liquid reservoir 6 will rise rapidly and as a result the membrane 5 will be deformed to eject all the sample liquid from the sample liquid reservoir 7.
  • the optimal pressure P e j ec t depends on the specific dimensions of the dispenser. Primarily it depends on the length and the diameter of the nozzle 15. The greater the length and the smaller is the diameter, the greater is the pressure required to ensure that the sample liquid expelled from the sample liquid reservoir gets detached from the tip 16.
  • the pressure should not be too great to avoid damage to the membrane 5 and also for the reason that some biological liquids should not be subjected to an excessive pressure.
  • the pressure in the range of up to 5 Bar is often adequate for the dispensation in the range of the order of 10 nl. In some cases, especially when dispensing liquids with higher viscosity such as e.g. glycerol, greater pressure in the range of 10 to 30 Bar can be preferable.
  • Fig. 25 there is illustrated an alternative construction of dispensing assembly, again indicated generally by the reference numeral 1 , which is substantially similar to the dispensing assembly illustrated in Fig. 24 and thus parts similar to those described with reference to Fig. 24 are identified by the same reference numerals.
  • a valve 102 in the line 100 between the compressor 99 and the high-speed valve 98.
  • a further pressure release valve 103 is provided.
  • a liquid level detector comprising a laser diode 105 and a photodiode 104 is also provided.
  • a photodiode is connected to the controller 13.
  • the laser diode 105 focuses a laser beam on the line 100, and the photodiode 104 receives the light that has passed through the control line 100. As the level of liquid 101 passes through the focused laser beam, the signal received by the photodiode 104 changes.
  • the photodiode and the laser diode are connected to their respective control circuits that are not shown in Fig. 25 .
  • Those skilled in the art can readily propose numerous other means for control of the level of system liquid including in the control line optical and non-optical means. Those skilled in the art can further appreciate that if optical means of the level control are employed then the control line should be preferably optically transparent.
  • the system liquid is dyed with an ink to improve sensitivity of monitoring of the level of liquid.
  • the dispensing assembly operates as follows.
  • the level of liquid in the control line 100 is maintained constant at certain stages of the aspirate-dispense cycle. All the walls of the control line 100 and tubing 97 joining the high-speed valve 98 and the tubing 1 1 are non-expandable. If one considers that the liquid up to the height of the level of liquid in the control line also forms a part of the system liquid reservoir, then it is clear that all the above analysis of the dispensing assembly applies here.
  • the high-speed valve 98 is closed and the syringe pump 10 has its plunger 9 pulled back by the volume V as to aspirate system liquid.
  • the level of liquid 101 in the control line 100 is equal to lo.
  • valve 103 and the high-speed valve 98 are kept closed. Valve 102 is open. Then the control line 100 is pressurised. This does not change the level l 0 as the control line is non-expandable.
  • the high-speed valve 98 is open, the sample liquid is expelled from the dispenser 2 as explained with reference to Fig. 24.
  • the aspirate phase starts with the routine to bring up the level of the system liquid in the control line 100 to the same height l 0 .
  • the valve 102 closes and the high-speed valve 98 opens.
  • the valve 103 is opened preferably in short intervals or pulses so that the level of liquid in the control line becomes equal to the same value lo.
  • Means for monitoring the level of system liquid in the control line 100 can also be used to eject fractions of the volume of sample liquid aspirated.
  • the volume of the sample liquid ejected is determined by the duration of the time interval during which the high-speed valve 98 is open, the pressure in the control line 100, viscosity of the liquid and cross-sectional area of the nozzlel 5 and tubing 1 1.
  • the volume expelled is calculated as the height difference between the levels of the system liquid in the control line 100 before and after the ejection multiplied by the cross-sectional area of the control-line.
  • Fig. 26 there is illustrated an alternative construction of dispensing assembly, again indicated generally by the reference numeral 1 , which dispensing assembly is substantially similar to the dispensing assembly illustrated in Fig. 24, except that instead there is interposed in the tubing 97, a valve 110 incorporating a membrane 111.
  • a different system liquid may be used although it may be the same system liquid but is separated from the rest of the system liquid by the membrane 111.
  • the dispensing assembly operates in substantially the same way as heretofore, the advantage being that there is no need to top up the control line 100.
  • the compression wave generator comprises a mechanical actuator, indicated generally by the reference numeral 115, comprising a lever arm 116 pivotally mounted intermediate its ends by a pivot pin 117 mounted on a fulcrum 118.
  • the lever arm 1 16 carries a hammer head 119 through which the tubing 11 projects.
  • a stop 120 is mounted above the lever arm 116.
  • the end of the lever arm 116 opposite the hammer head 119 carries a soft magnetic core 121 housed within coil 122 driven by the current pulse generator 58.
  • a return spring 123 is also provided. If the coil 122 is energised by a current pulse, there is a force pulling the soft magnetic core 121 into the coil. As a result, the hammer head 119 accelerates and hits the inner part 3 of the dispenser 2 thus exciting a compression wave. In the absence of the current in the coil 122, the hammer rests against the stop 120. The amplitude of the movement of the hammer head 119, under the influence of the spring 123, depends on the specific design of hammer head and the magnetic actuator formed by the core 121 and coil 122.
  • hammer head 1 19 resting on the inner part 3 of the dispenser 2 and with the hammer head resting against the stop 120.
  • Fig. 28 there is illustrated another construction of dispenser, again indicated generally by the reference numeral 2, in which parts similar to those described with reference to the previous drawings are identified by the same reference numerals.
  • a compression wave generator namely, a magnetic actuator, indicated generally by the reference numeral 125.
  • the magnetic actuator 125 comprises a two part core, namely, an upper part 126 and a lower part 127 connected together by a hinge joint 128.
  • the lower part 127 is mounted on the inner part 3 of the dispenser 2.
  • the upper part 126 is urged away from the lower part 127 by an expansion spring 129.
  • a coil 130 is mounted around the upper part 126. The coil is again connected to the current pulse generator 58.
  • the upper part 126 is separated from the lower part 127 by a gap of some several millimetres.
  • the two parts 126 and 127 of the magnetic core attract each other and if the current is sufficiently strong, the core gap will close, resulting in controlled collision of the parts 126 and 127. Therefore, the lower part 127 will transmit a compression wave through the inner part 3.
  • a dispensing assembly indicated generally by the reference numeral 1 incorporating a dispenser 2 as described above . Parts similar to those described with reference to the previous drawings are identified by the same reference numerals.
  • the droplets are identified by the numeral 140 and successive subscripts thus 140(a) to 140(c) .
  • the dispensing tip 16 effectively forms or incorporates an electrode by virtue of being grounded by an earth line 141.
  • a receiving substrate 145 incorporating reagent wells, identified by the reference numeral 146 and three of which are identified by successive subscripts a, b and c.
  • a receiving electrode 147 Positioned below the receiving substrate 145 is a receiving electrode 147 in turn mounted on a synchronous indexing means 148, namely, an indexing table.
  • the receiving electrode 147 is connected to a high voltage source 149.
  • the indexing table 148 is used to position the receiving electrode 147 below the appropriate reagent well 146 as shown by the interrupted lines in the drawing. It should be noted that alternatively the nozzle 15 could be connected to the high voltage source 149 and the receiving electrode could be connected to the round potential. Indeed other arrangements are possible resulting in electrostatic field between the dispensing tip 16 and the receiving electrode 147.
  • Fig. 30 there is illustrated an alternative construction of dispensing assembly, in which parts similar to those described in Fig. 29 are identified by the same reference numerals.
  • this embodiment there is provided a plurality of receiving electrodes 150 on the indexing table 148, which are individually connected to the high voltage source 149.
  • Fig. 31 there is illustrated still further construction of dispensing assembly 1 in which parts similar to those described with reference to Fig. 30 are identified by the same reference numerals.
  • additional deflecting electrodes 155 and 156 it will be appreciated that depending on the voltage on the deflecting electrodes 155 and 156, the droplets 140 will in conjunction with the receiving electrodes 147 navigate into the appropriate reagent well 146. This is illustrated clearly in Fig. 31 by the interrupted lines.
  • Fig. 31 there is also shown a receiving electrode 147 but it will be appreciated that such a receiving electrode 147 will not always be necessary. It is also possible to use a conducting plate such as illustrated in Fig. 2 or it is possible to use only deflecting electrodes.
  • the receiving electrode could be in the form of a plate having at least one hole to allow a droplet pass therethrough.
  • the size between the subsequent droplets covering the substrate herein called pitch, could be as small as 0.1 mm.
  • the first way is to generate the electrostatic field with a small charged drop off or receiving electrode positioned underneath the well instead of a large conducting plate.
  • the size of the electrode is smaller than the size of the well for accurate navigation. It may be advantageous as described above to have the receiving electrode in the shape of a tip to produce the strongest electric field at the centre of a destination well.
  • the electrode produces a strong electric field underneath the well attracting the droplet to the required destination position (usually the centre of the well).
  • the receiving electrode may be attached to an arm of a positioner capable of moving it underneath the well plate and pointing to the correct destination well. Alternatively, the sample well plate may be repositioned above the receiving ' electrode in order to target a different well. It may be necessary to move the dispensing tip and receiving electrode synchronously.
  • the distance between the electrodes could be the same as the distance between the centres of the wells in a well plate. In this case the droplets could be navigated to different wells without actually moving the dispenser or the receiving electrode.
  • deflection electrodes are positioned along the path between the nozzle and the destination well.
  • the electrodes are charged by means of a high voltage applied to them.
  • the droplets leaving the dispensing tip are charged by the voltage between the dispensing tip and the receiving electrode, they will be deflected by the deflection electrodes.
  • the electrostatic force acting on the droplet could much greater than the gravity force.
  • the direction of the path is determined by the direction of the electrostatic field.
  • the electrostatic field required to detach a droplet from the tip is a function of the volume of the suspended droplet on the dispensing tip. It becomes important to ascertain exactly when the droplet is released from the dispensing tip. Accordingly, the invention provides various methods of detection of the separation of a droplet from the ..dispensing tip. Once the electrostatic force causing the drop off to be achieved is known, then the volume of the droplet can be calculated within relatively fine limits. While in many instances, it is necessary to calibrate the dispenser for each new liquid because the field required for droplet detachment depends on the properties of the liquid and of the nozzle, in certain instances this is not required.
  • a detector indicated generally by the reference numeral 160 for sensing the separation of a droplet from the dispensing tip.
  • the dispenser 2 is illustrated.
  • the detector 160 comprises source 161 of electromagnetic radiation, a collector of electromagnetic radiation 162 and a controller 163 connected to the electromagnetic radiation source 161 and collector 162.
  • the electromagnetic radiation source 161 is a laser.
  • a laser beam 164 emanating from the electromagnetic radiation source 161 and then either being reflected by the suspended droplet as a further laser beam 165 to the electromagnetic collector 162 or as a beam 166 passing straight beyond the dispensing tip 16 when a droplet 155 is not in position. It will be appreciated that only a fraction of the laser beam 164 returns as the beam 165 to the electromagnetic radiation collector 162.
  • embodiments can be devised in which the electromagnetic radiation from the source 161 reaches the collector 162 as it is refracted by the droplet suspended at the tip. As the droplet is removed from the tip, the amount of radiation reaching the collector 162 changes.
  • the radiation from the source 161 reaches the collector 162 as it is absorbed by the droplet again resulting in the same effect of changing the intensity of radiation collected by the collector 162 caused by the droplet detachment.
  • the monitoring of the droplet in flight is envisaged by means of a charge measuring device such as Faraday cup.
  • a charge measuring device such as Faraday cup. This is feasible as the droplet pulled off from the dispensing tip by electrostatic field, will be charged. It is important in many instances to be absolutely certain that the droplet was actually dispensed and ideally also to ascertain the volume of the droplet and this has been described above.
  • Fig. 33 there is illustrated an alternative construction of dispensing assembly, again indicated generally by the reference numeral 1.
  • the dispensing assembly is substantially similar to the dispensing assembly of Fig. 12 and thus parts similar to those described with reference to Fig. 12 are identified by the same reference numerals.
  • the dispenser 2 comprises again, an inner part 3 and a nozzle mounting part 4, the nozzle mounting part 4 now mounts a plurality of nozzles 15 and the divider barrier which is again formed from the membrane 5 which additionally separates portion of the main bore adjacent each nozzle entrance to form separate sample liquid containing portions 7 divided from the one system liquid containing portion 6.
  • the reference numeral 2 it is not one dispenser but a plurality of dispensers 2, however, it is preferable to still identify them by the reference numeral 2 to avoid the use of subscript letters which would be confusing.
  • electrostatic receiving electrodes 45 positioned in the vicinity of the tips 16 of the nozzles 15.
  • the droplets are detached from the nozzles 15 by means of electrostatic field as these receiving electrodes 45 are connected to the high voltage source.
  • the receiving electrodes are connected to the high voltage source 26 through a multiplexer unit 170 so that individual receiving electrodes can be connected to the high voltage source 26 separately if required to detach droplets from the selected nozzles 15.
  • Fig 33 shows an embodiment of a dispensing assembly in which a number of different liquids can be aspirated and dispensed by means of single syringe pump 10.
  • the most likely application of this device is simultaneous aspiration and dispensing of equal amounts of a number of liquids without intermixing. For example, it can be necessary to aspirate 48, 96, 384, 1536 or another number of liquids from a well plate and dispense these onto a target substrate or another well plate or a microchannel structure.
  • All the system liquid reservoirs of the dispenser 2 are hydraulically connected to the syringe pump 10. If all the membranes 5 in, what are effectively, separate dispensers, are identical, the volume of the system liquid expelled by the syringe pump will- be divided equally between the individual dispensers. For example if the volume of the system liquid expelled by the syringe pump is 960 nl and there are 96 dispensers in the assembly, the volume of the sample liquid expelled from each of the dispensers is 10 nl. If the membranes are not identical, then the volume
  • the dispensing assembly can employ a compression wave generator or pressure source as described in above embodiments.
  • the membranes In order to have equal volumes of sample liquid expelled from the individual dispensers, it is advantageous to have the membranes substantially pre-stretched during the entire dispensing step. The reason is that even if the membranes are identical, the volume expelled by the syringe pump may not be equally divided between the dispensers if the membranes are loose. It is desirable that identical additional extension of the membranes results in identical pressure increase in the individual dispensers. It is therefore advantageous to operate the assembly at a considerable excess pressure above the atmospheric pressure. The simplest solution can be to ensure that during the aspiration, the membrane is not allowed to become flat and remains always considerably bent towards .the nozzle mounting part of the dispenser.
  • dispensers in which the membranes at different dispensers are not identical. For example, one could design a dispenser in which the membranes on all the odd channels are twice as stiff as the ones of the even channels. This dispenser could be used for an application whereby it is necessary to dispense unequal amounts of liquids or dispense only liquids from some dispensers.
  • a dispensing assembly in which individual dispensers are controlled by means of individual syringes, can also be designed. This can offer greater flexibility in the control of the individual dispensers that may be of benefit for certain applications.
  • a dispensing assembly substantially identical to the dispensing assembly illustrated in Fig. 33.
  • a combined high voltage source and multiplexer 175 provided and there are no nozzles projecting from the dispenser 2.
  • Fig. 35 shows another embodiment dispenser 2 in which instead of a membrane clamped between the inner part 3 and the nozzle mounting part 4, there are flexible elastomer containers 176 in the shape of bells, spaced-apart on a sheet 177, separating the sample liquid reservoir 6 from the system liquid reservoir 7. The bells are compressed by the pressure in the system liquid reservoir 6 and expel sample liquid from the sample liquid reservoirs 7.
  • the embodiment of Fig. 35 shows a composite dispenser with four nozzles . It is clear that dispensing assemblies with other numbers of individual dispensers can also be designed. The means for droplet detachment from the end of the nozzles 15 are not shown . These could be similar to any of the means described above.
  • Fig. 36 there is illustrated an alternative construction of dispensing assembly, again indicated generally by the reference numeral 1 , substantially identical to the dispensing assembly illustrated in Fig. 13, except that instead of one syringe pump 10, there is a syringe pump 10a and a syringe pump 10b, together with associated motors 12a and 12b.
  • the pump 10b is a small volume pump and is used for accurate dispensing of small volumes.
  • the pump 10a is a larger volume pump.
  • the pumps are mounted in parallel.
  • This arrangement is used to achieve a large dynamic range.
  • the two pumps 10a and 10b installed in parallel can operate in a co-ordinated manner to achieve. both a large dynamic range and high precision for dispensing small volumes.
  • the pumps 10a and 10b which will be positive displacement pumps such as syringe pumps, will be so constructed that one pump will have a working stroke displacing a volume, at least about ten times larger than that of the other pump. Indeed, in many instances, the difference in displacing a volume from one stroke of the larger ' pump will be twenty or more times greater than the displacement of the smaller pump.
  • EP application No 00650123.3 For independent measurement of the droplet volume, one could use means described in EP application No 00650123.3. These include an electromagnetic balance based on a coil suspended in a magnetic field or another suitable balance.
  • electrostatic field is used for the drop off
  • Monitoring of the moment of the drop off could be achieved by e.g. coupling electromagnetic radiation from a source to a detector through the droplet suspended at the dispensing tip and monitoring the change in signal received by the detector caused by the drop off.

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  • Health & Medical Sciences (AREA)
  • Clinical Laboratory Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Sampling And Sample Adjustment (AREA)
  • Automatic Analysis And Handling Materials Therefor (AREA)

Abstract

L'invention concerne une pompe seringue classique (10) utilisée pour distribuer des liquides en volume inférieur à 5 νl dans un ensemble de distribution (1). Une barrière de séparation formée par une membrane élastomère souple (5) est logée entre une partie intérieure (3) et une partie extérieure (4) d'un distributeur (2). Ce distributeur (2) comporte un alésage divisé en un réservoir de liquide systémique (6) et un réservoir de liquide échantillon (7). Le réservoir de liquide systémique (6) est relié à la pompe (10), le réservoir de liquide échantillon (7) communiquant avec une buse (15) munie d'un embout de distribution (16). Ladite membrane (5) est pratiquement incompressible, la pompe (10) permettant ainsi de réaliser une distribution précise. L'invention concerne également un système de séparation de gouttelettes par voie électrostatique utilisant une électrode (25) couplée électriquement à l'embout de distribution (16) ainsi qu'une plaque conductrice (19) formant une électrode de réception en dessous d'un substrat (20). Cet ensemble de distribution est particulièrement utile pour des ensembles de distribution à buses multiples.
PCT/IE2002/000061 2001-05-11 2002-05-02 Procede et dispositif de distribution de gouttelettes WO2002092228A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP02727994A EP1385629A2 (fr) 2001-05-11 2002-05-02 Procede et dispositif de distribution de gouttelettes

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
IE20010457 2001-05-11
IE2001/0457 2001-05-11
US09/927,355 US20020168297A1 (en) 2001-05-11 2001-08-13 Method and device for dispensing of droplets
US09/927,355 2001-08-13

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WO2002092228A2 true WO2002092228A2 (fr) 2002-11-21
WO2002092228A3 WO2002092228A3 (fr) 2003-03-13

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1568415A2 (fr) * 2004-02-27 2005-08-31 Allegro Research Limited Méthode et dispositif pour mesurer les gouttelettes
DE102005002525A1 (de) * 2005-01-19 2006-07-27 Zengerle, Roland, Prof. Dr. Pipettenspitze, Pipetiervorrichtung, Pipettenspitzen-Betätigungsvorrichtung und Verfahren zum Pipetieren im nL-Bereich
DE102005014572A1 (de) * 2005-03-31 2006-10-12 Eppendorf Ag Pipettiervorrichtung
DE102007005323A1 (de) * 2007-01-29 2008-07-31 Bioplan Consulting Gmbh Absaugeinrichtung
DE102010045452A1 (de) 2010-09-15 2012-03-15 Hamilton Robotics Gmbh Dosiereinrichtung mit Membran
WO2013045711A1 (fr) * 2011-09-30 2013-04-04 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V. Procédé et dispositif pour doser un fluide de travail
EP2860529A1 (fr) * 2013-10-08 2015-04-15 Roche Diagniostics GmbH Cartouche de distribution de fluide comprenant une vessie flexible
WO2023057566A1 (fr) * 2021-10-06 2023-04-13 Shape Engineering GmbH Procédé, récipient et agencement pour distribuer une substance fluide

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109060594B (zh) * 2018-06-22 2021-07-16 北京市医疗器械检验所 一种液体密度测量方法

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US3572552A (en) * 1969-07-25 1971-03-30 Perry W Guinn Diaphragm dispenser
US4537231A (en) * 1983-08-29 1985-08-27 Becton, Dickinson And Company Dispenser apparatus for simultaneously dispensing predetermined equal volumes of liquid including a disposable dispenser module
US5085345A (en) * 1985-04-12 1992-02-04 Wells John R Hydraulic dispenser
EP0820811A2 (fr) * 1993-06-25 1998-01-28 Jack Goodman Dispositif de transfert de liquides
US6165417A (en) * 1998-10-26 2000-12-26 The Regents Of The University Of California Integrated titer plate-injector head for microdrop array preparation, storage and transfer

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3572552A (en) * 1969-07-25 1971-03-30 Perry W Guinn Diaphragm dispenser
US4537231A (en) * 1983-08-29 1985-08-27 Becton, Dickinson And Company Dispenser apparatus for simultaneously dispensing predetermined equal volumes of liquid including a disposable dispenser module
US5085345A (en) * 1985-04-12 1992-02-04 Wells John R Hydraulic dispenser
EP0820811A2 (fr) * 1993-06-25 1998-01-28 Jack Goodman Dispositif de transfert de liquides
US6165417A (en) * 1998-10-26 2000-12-26 The Regents Of The University Of California Integrated titer plate-injector head for microdrop array preparation, storage and transfer

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1568415A2 (fr) * 2004-02-27 2005-08-31 Allegro Research Limited Méthode et dispositif pour mesurer les gouttelettes
EP1568415A3 (fr) * 2004-02-27 2007-04-04 Allegro Research Limited Méthode et dispositif pour mesurer les gouttelettes
DE102005002525A1 (de) * 2005-01-19 2006-07-27 Zengerle, Roland, Prof. Dr. Pipettenspitze, Pipetiervorrichtung, Pipettenspitzen-Betätigungsvorrichtung und Verfahren zum Pipetieren im nL-Bereich
US8071049B2 (en) 2005-01-19 2011-12-06 Roland Zengerle Pipette tip, pipetting device, pipette tip actuating device and method for pipetting in the NL range
DE102005014572A1 (de) * 2005-03-31 2006-10-12 Eppendorf Ag Pipettiervorrichtung
DE102005014572B4 (de) * 2005-03-31 2007-01-04 Eppendorf Ag Pipettiervorrichtung
US8021627B2 (en) 2005-03-31 2011-09-20 Eppendorf Ag Pipetting device
DE102007005323A1 (de) * 2007-01-29 2008-07-31 Bioplan Consulting Gmbh Absaugeinrichtung
DE102010045452A1 (de) 2010-09-15 2012-03-15 Hamilton Robotics Gmbh Dosiereinrichtung mit Membran
WO2013045711A1 (fr) * 2011-09-30 2013-04-04 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V. Procédé et dispositif pour doser un fluide de travail
EP2860529A1 (fr) * 2013-10-08 2015-04-15 Roche Diagniostics GmbH Cartouche de distribution de fluide comprenant une vessie flexible
WO2015052069A1 (fr) * 2013-10-08 2015-04-16 Roche Diagnostics Gmbh Procédé permettant de réaliser une mesure d'un analyte dans un échantillon à l'aide d'un analyseur automatique
CN105556316A (zh) * 2013-10-08 2016-05-04 豪夫迈·罗氏有限公司 使用自动分析器执行对样品中的分析物的测量的方法
JP2016532880A (ja) * 2013-10-08 2016-10-20 エフ．ホフマン−ラ ロシュ アーゲーＦ． Ｈｏｆｆｍａｎｎ−Ｌａ Ｒｏｃｈｅ Ａｋｔｉｅｎｇｅｓｅｌｌｓｃｈａｆｔ 自動分析器を使用して試料中の分析物の測定を実施するための方法
US10241124B2 (en) 2013-10-08 2019-03-26 Roche Diagnostics Operations, Inc. Method to perform a measurement of an analyte in a sample using an automatic analyzer
WO2023057566A1 (fr) * 2021-10-06 2023-04-13 Shape Engineering GmbH Procédé, récipient et agencement pour distribuer une substance fluide

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WO2002092228A3 (fr) 2003-03-13

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