EP1284808A1 - Separation de micromolecules - Google Patents

Separation de micromolecules

Info

Publication number
EP1284808A1
EP1284808A1 EP01923390A EP01923390A EP1284808A1 EP 1284808 A1 EP1284808 A1 EP 1284808A1 EP 01923390 A EP01923390 A EP 01923390A EP 01923390 A EP01923390 A EP 01923390A EP 1284808 A1 EP1284808 A1 EP 1284808A1
Authority
EP
European Patent Office
Prior art keywords
membrane
separation
chamber
molecular mass
restriction
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP01923390A
Other languages
German (de)
English (en)
Other versions
EP1284808A4 (fr
Inventor
Brendon Francis Conlan
Andrew Mark Gilbert
Lucy Jane Ryan
Chenicheri Hariharan Nair
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Life Therapeutics Ltd
Original Assignee
Gradipore Ltd
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 AUPQ6914A external-priority patent/AUPQ691400A0/en
Application filed by Gradipore Ltd filed Critical Gradipore Ltd
Publication of EP1284808A1 publication Critical patent/EP1284808A1/fr
Publication of EP1284808A4 publication Critical patent/EP1284808A4/fr
Withdrawn legal-status Critical Current

Links

Definitions

  • the present invention relates to apparatus and methods for the separation of molecules, particularly micromolecules having a molecular mass of less than about 5000 Dalton.
  • micromolecules there are increasing numbers of micromolecules being used as food and diet supplements, pharmaceuticals and neutraceuticals. Increasing numbers of vitamins, co- factors, plant and microbial extracts are also being developed and used for human and animal consumption. As many of these compounds are micromolecules (having a molecular mass of less than about 5000 Dalton (Da)), there is a need to develop methods to separate or purify these compounds in a fast and economical manner. Traditional separation methods for micromolecules can alter or denature these compounds.
  • a preparative electrophoresis technology for macromolecule separation which utilises tangential flow across a polyacrylamide membrane when a charge is applied across the membrane was used to separate micromolecules.
  • the general design of the earlier system facilitated the purification of proteins and other macromolecules under near native conditions.
  • the technology is bundled into a cartridge comprising several membranes housed in a system of specially engineered grids and gaskets which allow separation of macromolecules by charge and/or molecular weight.
  • the system can also concentrate and desalt/dialyse at the same time.
  • the multi-modal nature of the system allows this technology to be used in a number of other areas especially in the production of biological components for medical use.
  • the technology isolates macromolecules using the duality of charge and size.
  • the technology could not be extended to the isolation of molecules below about 5000 Da. This meant that while molecules smaller than 5000 Da could be removed using at least charge-based separation, the resulting target molecule could not be captured.
  • the separation of micromolecules molecules deemed to be less than about 5 kDa, was previously thought not to be possible using electrophoresis technology devised to separate macromolecules. This was due to the limit in pore size of membranes normally used in the systems. For example, the smallest cut-off produced in polyaccrylamide. membranes is about 5 kDa which will retain any molecule larger than 5 kDa.
  • the subject invention overcomes the above limitations and others, and teaches an electrophoresis system, which can be scaled up for preparative applications, which apparatus can efficiently and effectively separate micromolecules.
  • an electrophoresis system which efficiently and effectively separates micromolecules.
  • an apparatus for separating micromolecules by electrophoretic separation comprising: (a) a cathode; (b) an anode disposed relative to the anode so as to be adapted to generate an electric field in an electric field area therebetween upon application of a voltage potential between the cathode and the anode;
  • a second restriction membrane disposed between the anode and the separation membrane so as to define a second interstitial volume therebetween; and (f) means adapted to provide a sample constituent in a selected one of the first and second interstitial volumes; wherein upon application of the voltage potential, a selected separation product is removed from the sample constituent, thorough the separation membrane, and provided to the other of the first and second interstitial volumes, wherein a micromolecule is capable of being retained in at least one of the interstitial volumes.
  • an apparatus for separating micromolecules by electrophoresis comprising :- (a) a cathode compartment and an anode compartment;
  • a first chamber and a second chamber positioned on either side of an ion- permeable separation membrane having a defined molecular mass cut-off, the first chamber and the second chamber being positioned between the cathode and the anode compartments and separated by an ion-permeable restriction membrane positioned on each side of the separation membrane, the restriction membrane(s) allowing flow of ions into and out of the compartments and chambers under the influence of an electric field but substantially restrict movement of at least one micromolecule type from the second chamber into the cathode and anode compartments.
  • the cathode compartment and the anode compartment are supplied with suitable buffer solutions by any suitable means.
  • a mixture comprising micromolecules is supplied directly to the first chamber by any suitable means.
  • the micromolecules are separated from the second chamber by any suitable means.
  • the electrode compartments, the first chamber and the second chamber are configured to allow flow of the respective buffer, sample and product solutions forming streams.
  • the solutions are typically moved or recirculated through the compartments and chambers from respective reservoirs by pumping means.
  • peristaltic pumps are used as the pumping means for moving the fluids.
  • the buffer, sample or other solutions can be cooled by any suitable means to ensure no inactivation of the micromolecules occurs during the separation process and to maintained a desired temperature of the apparatus while in use.
  • solution in the second chamber or stream is collected and replaced with suitable solvent to ensure that electrophoresis can continue.
  • At least one restriction membrane is formed as a composite or sandwich arrangement with at least two materials.
  • at least one restriction membrane is formed as a sandwich arrangement with at least two layers of material.
  • the sandwich arrangement includes an inner layer (facing the separation membrane in the first and second solvent streams, respectively) comprising a membrane having a pore size with a molecular mass cut-off less than the about 5000 Da and an outer layer comprising a membrane having a molecular mass cut-off of greater than about 5000 Da.
  • the inner layer is made from an ultrafiltration, electrodialysis or haemodialysis material and the outer layer is made from polyacrylamide.
  • the outer layer provides some structural support for the filtration membrane while preventing unwanted movement of fluid.
  • the pore size of the filtration membrane is selected according to the size of the micromolecule to be separated such that the micromolecule cannot pass through the membrane.
  • the molecular mass cut-off of the filtration membrane is between about 100 Da to 5000 Da. More preferably, the molecular mass cut-off is around 200 Da.
  • Hydrogel ion-permeable separation membranes (an ultrafiltration, electrodialysis and/or haemodialysis membranes coated with polyacrylamide) would be an alternative membrane type suitable for the present invention. Such membranes are possible to manufacture, but are currently not commercially available.
  • the ion-permeable separation barrier is a membrane made from polyacrylamide and having a molecular mass cut-off from about 5 to 1000 kDa.
  • the size of the separation membrane cut-off will depend on the sample being processed and the other molecules in the mixture.
  • the restriction barriers or membranes positioned adjacent the sample and product chambers can have the same molecular mass cut-off or different cut-offs therefore forming an asymmetrical arrangement.
  • the restriction membrane separating the product chamber from the buffer compartment is formed in a sandwich configuration.
  • the distance between the electrodes can have an effect on the separation or movement of micromolecules through the membranes. It has been found that the shorter the distance between the electrodes, the faster the electrophoretic movement of micromolecules. A distance of about 6 cm has been found to be suitable for a laboratory scale apparatus. For scale up versions, the distance will depend on the number and type of separation membranes, the size and volume of the chambers for samples, buffers and separated products. Preferred distances would be in the order of about 6 cm to about 10 cm. The distance will also relate to the voltage applied to the apparatus. The effect of the electric field is based on the equation:
  • the distance between the electrodes should decrease in order to increase electric field strength, thereby further improving transfer rates.
  • Flow rate of sample/buffer can have an influence on the separation of micromolecules. Rates of millilitres per hour up to litres per hour can be used depending on the configuration of the apparatus and the sample to be separated; Currently in ' a laboratory scale instrument, the preferred flow rate is about 20 ⁇ 5 mL/min. However, flow rates ranging from about 0 to about 50,000 mL/min could be used across the various separation regimes. In some embodiments, maximum flow rate is even higher, depending on the pumping means and size of the apparatus. The flow rate is dependent on the product to be transferred, efficiency of transfer, pre- and post- positioning with . other applications.
  • Voltage and/or current applied can vary depending on the separation. Typically up to several thousand volts may be used but choice and variation of voltage will depend on the configuration of the apparatus, buffers and the sample to be separated. In a laboratory scale instrument, the preferred voltage is about 250 V. However, depending on transfer, efficiency, scale-up and particular method about 0 to about 5000V can be used. Higher voltages may also be considered, depending on the apparatus and sample to be treated. A number of first and second chambers could be stacked in the one apparatus for use in a scale-up device.
  • a single stream configuration can be produced where the second chamber forms a buffer chamber. In this configuration, contaminants would be moved out of the first chamber into the buffer compartments and the product of interest retained in the first chamber.
  • the membranes can have either a symmetric or asymmetric arrangements. The present invention also includes these embodiments.
  • a sample containing one or more micromolecules is added to the first chamber and an electric potential is applied to cause movement of at least one micromolecule from the sample through the separation membrane into the second chamber while the restriction membranes prevent movement of micromolecules from the first or the second chambers into the respective electrophoresis buffer chambers.
  • the micromolecule is removed and collected from the product chamber.
  • the present invention provides a separation cartridge suitable for use in an electrophoresis apparatus for separating micromolecules, the cartridge comprising:
  • an ion-permeable separation membrane having a defined molecular mass cut-off positioned in the housing;
  • an ion-permeable restriction membrane positioned on either side of the separation membrane in the housing and spaced to form a first chamber and second chamber on either side of the separation membrane, wherein the restriction membrane is adapted to allow flow of ions into and out of the. compartments and chambers under the influence of an electric field but substantially restrict movement of at least one micromolecule type from the second chamber.
  • the cartridge further includes: (d) electrodes positioned in the housing on the outer sides of the restriction barriers.
  • the separation barrier is a membrane composed of polyacrylamide and having a molecular mass cut-off from about 5 to 1000 kDa.
  • the ion-permeable separation membrane has a molecular mass cut-off greater than the molecular mass of the micromolecule to be separated.
  • At least one restriction membrane is preferably formed as a sandwich or composite arrangement of membranes with at least two materials.
  • the sandwich arrangement includes an inner layer comprising a restriction membrane having a pore size with a molecular mass cut-off less than about 5000- Da and an outer layer comprising a restriction membrane having a molecular mass cut-off of greater than about 5000 Da.
  • the inner layer is made from an ultrafiltration, electrodialysis or haemodialysis material and the outer layer is made from polyacrylamide.
  • the outer layer provides some structural support for the filtration membrane while preventing unwanted movement of fluid.
  • the pore size of the filtration membrane is selected according to the size of the micromolecule to be separated such that the micromolecule cannot pass through the membrane.
  • the molecular mass cut-off of the filtration membrane is between about 100 Da to 5000 Da. More preferably, the molecular mass cut-off is around 200 Da.
  • the present invention provides a method of separating a micromolecule from a liquid sample, the method comprising:
  • the micromolecule can be any micromolecule capable of receiving or having a charge. Examples include, but not limited to, biotin , Brilliant Blue FCF (BB FCF), azorubine, phytoestrogen, digoxigenin, hormones, cytokines, dyes, vitamins, chemicals, neutraceuticals, pharmaceuticals along with food and diet supplements.
  • the sample can contain one or more micromolecules of interest. Examples include, but are not limited to, crude extracts, microbial cultures, cell lysates, cellular products, chemical processing mixtures, cell culture media, plant products or extracts. Solvent in the form of buffers that have been found to be particularly suitable for the method according to the present invention are Tris Borate around pH 9.
  • concentration of the selected buffers can also influence or effect the movement of micromolecules through the separation barrier. Typically concentrations of about 10 mM to about 200 mM, more preferably 20 mM to 80 mM, have been found to be particularly suitable. Almost any buffers and/or solvents can be used with the present invention.
  • the buffers and/or solvents that can be used are procedure/method/separation dependent. The concentration of the buffer and/or solvent is dependent upon the application/separation/procedure.
  • Reversal of current is an option but another embodiment is a resting period. Resting (a period without an electric potential being applied, but pumps remain on) is an optional step that can replace or be included before or after an optional electrical potential reversal. This resting technique is often practised for protein separation work as an alternative to reversing the potential.
  • One benefit of the method according to the present invention is the possibility of scale- up without denaturing or adversely altering the physical or biological properties of the micromolecule.
  • the present invention provides a micromolecule purified or separated by the method according to the third aspect of the present invention.
  • the micromolecule is less than 5000 Da.
  • examples include, but are not limited to, biotin , Brilliant Blue FCF (BB FCF), azorubine, phytoestrogen, digoxigenin, hormones, cytokines, dyes, vitamins, chemicals, neutraceuticals, pharmaceuticals along with food, supplements, and combinations thereof.
  • the present invention relates to use of the micromolecule according to the fourth aspect of the present invention in dietary, medical and veterinary applications.
  • Figure 1 shows the transfer of BB-FCF through the 5 kDa separation membrane from the first stream (US) where it transiently builds up in the second stream (DS). After 20 minutes all the BB-FCF had transferred through the bottom restriction membrane into • the buffer stream where it was lost.
  • Figure 2 shows Azorubine transfer using only polyacrylamide membranes in the
  • FIG. 3 shows that Biotin behaves in a similar manner to the other tested micromolecules in that it transferred rapidly from the first stream (US) and appeared transiently in the second stream (DS) before eluting into the buffer stream.
  • Figure 4 shows that phytoestrogen transferred into the second stream (DS) from the first stream (US), where it built up and over time before dissipating into the buffer stream.
  • Figure 5 shows BB-FCF separated with 74% yield in one hour. The molecules were readily captured using the 1 kDa ultrafiltration membrane in the cartridge.
  • Figure 6 shows the level of Azorubine in the first stream (US) decreased over time and transferred to the second stream (DS). A total of 83% of the Azorubine was transferred and retained in 45 minutes.
  • Figure 7 shows Biotin was readily transferred from the first stream into the second stream and collected with high yield (84%) in the second stream.
  • Figure 8 shows phytoestrogen was transferred from the first stream into the second stream where it could be collected.
  • Figure 9 shows separation of BB-FCF from Azorubine in a system adapted to carry out the method according to the present invention. The BB-FCF was retained in the first stream whilst the Azorubine was moved to the second stream.
  • Figure 10 shows BB-FCF was separated from Azorubine using a size exclusion approach with retention of 74% of the BB-FCF. Only a small percentage of the Azorubine remained with the BB-FCF after three hours of separation.
  • Figure 11 is a schematic view of a preferred embodiment of the separation apparatus of the present invention. .
  • This invention is directed to an apparatus and method for the separation of molecules, particularly micromolecules having a molecular mass of less than about 5000 Dalton.
  • the present invention is directed to an apparatus for separating micromolecules by electrophoretic separation, the apparatus comprising: (a) an anode;
  • the present invention is directed an apparatus for separating micromolecules by electrophoresis, the apparatus comprising:
  • electrodes positioned in the buffer compartments; (c) a first chamber and a second chamber positioned on either side of an ion- permeable separation membrane having a defined molecular mass cut-off, the first chamber and the second chamber being positioned between the cathode and the anode compartments and separated by an ion-permeable restriction membrane positioned on each side of the separation membrane, the restriction membrane(s) allowing flow of ions into and out of the compartments and chambers under the influence of an electric field but substantially restrict movement of at least one micromolecule type from the second chamber into the buffer compartment.
  • the buffer compartments, the first chamber and the second chamber are configured to allow flow of the respective buffer, first and second solutions forming streams.
  • the solutions are typically moved or recirculated through the compartments and chambers from respective reservoirs by pumping means.
  • Peristaltic pumps have been found to be particularly suitable for moving the fluids.
  • the ion-permeable separation membrane has a molecular mass cut-off greater than the molecular mass of the micromolecule to be separated.
  • FIG 11 shows a preferred embodiment of the apparatus 10 of the present invention.
  • the apparatus 10 includes an cathode zone or compartment 11 and a anode zone or compartment 12 separated by an ion-permeable separation barrier 13. Electrodes 14 and 15 are provided inside the buffer zones or compartments so as to be on opposite sides of the separation membrane 13. It is understood, however, that in another embodiment, the electrodes are positioned outside the buffer compartments. The electrodes are used to apply an electrophoretic potential across the separation membrane. '
  • a first chamber 16 is positioned between the cathode compartment 11 and the separation membrane 13. The first chamber is defined on one side by the separation membrane 13 and on the other side by a first restriction membrane 18. It is understood, however, that in another embodiment, the first chamber is positioned between the anode compartment and the separation membrane.
  • the first restriction membrane is comprised of at least two membranes 18 and 18b having distinctive pore sizes.
  • a second chamber 17 is positioned between the anode compartment 12 and the separation barrier 13.
  • the second chamber is defined on one side by the separation membrane 13 and on the other side by a second restriction membrane 19 on the other side. It is understood , however, that in another embodiment, the second chamber is positioned between the cathode compartment and the separation membrane.
  • the second restriction membrane is comprised of at least two membranes 19a and 19b having distinctive pore sizes.
  • the apparatus is further comprised of switch 25 for selection of the application of a voltage source (such as to turn the voltage source off or have resting periods), switch 26 to switch current direction for cathode/anode or to have reversal periods, and voltage sources 27 and 28.
  • the cathode compartment and the anode compartment are supplied with suitable buffer solutions by any suitable means.
  • a mixture comprising micromolecules is supplied directly to the first chamber by any suitable means.
  • the micromolecules are separated from the second chamber by any suitable means.
  • micromolecules molecules deemed to be less than about 5 kDa
  • electrophoresis technology devised to separate macromolecules. This was due to the limit in pore size of membranes normally used in the systems. For example, the smallest cut-off produced in polyaccrylamide membranes is about 5 kDa which will retain any molecule larger than 5 kDa.
  • the present invention results from modification of GradiflowTM technology to be capable of separating micromolecules by using some membranes other than polyacrylamide membranes traditionally used. It has been found that when commercially available membranes in ' the form of ultrafiltration, electrodialysis and haemodialysis membranes are used as separation or restriction membranes, the size of molecule that can be dealt with, is significantly smaller than previously thought.
  • hydrogel polyacrylamide membranes traditionally used in the GradiflowTM cartridge were placed as backing to a commercial membrane with the desired pore size.
  • the polyacrylamide membrane is useful to prevent unregulated fluid movement across the membranes, whilst the . commercial membrane is used to retain the smaller molecular species within the first or second streams or chambers.
  • the membranes used for this work were Pall German Omega ultrafiltration membranes. These ultrafiltration membranes are available commercially with pore sizes ranging from hundreds of kDa down to 1000 Da.
  • Vitamin H Vitamin H
  • the other a small phytoestrogen separated from red leaf clover (supplied by Novogen, Sydney Australia).
  • Brilliant Blue FCF and Azorubine are two chemicals currently used in the food industry as colouring agents.
  • Biotin has several uses, first as a necessary vitamin in the human diet and secondly, but not insignificantly, as a labelling agent in scientific assays.
  • Phytoestrogens are separated commercially from many sources primarily soy and clover where they are made into herbal and pharmaceutical medicines.
  • Azorubine was moved across the separation membrane and collected in the second stream. Using a pH 9.0 Tris-Borate buffer 83% of the Azorubine was transferred from the first stream to the second stream within 45 minutes. This transfer was measured using the absorbance of Azorubine at 516nm. The separation is illustrated in Figure 4.
  • the Biotin separation utilised a pH 9.0 buffer with the same cartridge configuration as that used for the BB-FCF and Azorubine. The transfer of this molecule was monitored using the absorbance at 230nm. This experiment showed that the 1 kDa ultrafiltration membrane used could retain molecules as small as 244 Dalton. Figure 7 shows that over 80% of the Biotin was transferred to the second stream where it was contained.
  • the phytoestrogen transfer experiment depicted in Figure 8 showed the movement and successful capture of phytoestrogen.
  • the decrease over time after the initial high levels of phytoestrogen are most likely due to the fact that a 5 kDa ultrafiltration membrane was used as the bottom restriction membrane.
  • the use of a 1 kDa ultrafiltration membrane would help to completely retain the small phytoestrogen.
  • Azorubine and BB-FCF be moved across a separation membrane from first stream to the second stream, these two molecules could also be separated from each other.
  • the two compounds were separated from each other using a size exclusion separation where the largest molecule was retained in the second stream whilst the smaller molecule was allowed to transfer through into the buffer stream.
  • BB-FCF was separated from Azorubine using the present invention.
  • Azorubine By allowing Azorubine to pass through the 3 kDa ultrafiltration membrane whilst retaining the BB- • FCF in the first stream, an adequate separation was achieved.
  • the concentration of Azorubine decreased significantly from the first stream but did not build up substantially in the second stream. This was due to loss into the buffer stream over .time.
  • the BB-FCF can pass through a 3 kDa membrane but only very slowly so separation of the two molecules was achieved. The movement of both molecules was monitored using 603nm for BB-FCF and 516nm for Azorubine.
  • Figure 9 shows the selective nature of the separation.
  • micromolecules less than 5 kDa were separated from mixtures containing more than one molecular species.
  • polyacrylamide membranes were used in combination with certain commercially available membranes, molecules as small as ⁇ 200 Da were be separated and purified.

Landscapes

  • Separation Using Semi-Permeable Membranes (AREA)
  • Sampling And Sample Adjustment (AREA)
  • Electrostatic Separation (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Abstract

L'invention concerne un appareil de séparation électrophorétique servant à séparer des micromolécules. Cet appareil comprend (a) une cathode; (b) une anode disposée par rapport à la cathode de manière à pouvoir générer un champ électrique dans une zone de champ électrique entre l'anode et la cathode, après application d'une tension électrique entre la cathode et l'anode; (c) une membrane de séparation placée dans la zone de champ électrique; (d) une première membrane de restriction placée entre la cathode et la membrane de séparation de manière à définir un premier volume interstitiel; (e) une deuxième membrane de restriction placée entre l'anode et la membrane de séparation de manière à définir un deuxième volume interstitiel; et (f) des moyens adaptés pour introduire un constituant échantillon dans l'un des premier et deuxième volumes interstitiels . Selon cette invention, après application de la tension électrique, un produit de séparation choisi est éliminé de l'échantillon, à travers la membrane de séparation, et est introduit dans l'autre des premier et deuxième volumes interstitiels, une micromolécule pouvant être retenue dans au moins l'un des volumes interstitiels.
EP01923390A 2000-04-14 2001-04-17 Separation de micromolecules Withdrawn EP1284808A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AUPQ6914A AUPQ691400A0 (en) 2000-04-14 2000-04-14 Separation of micromolecules
AUPQ691400 2000-04-14
PCT/AU2001/000433 WO2001078876A1 (fr) 2000-04-14 2001-04-17 Separation de micromolecules

Publications (2)

Publication Number Publication Date
EP1284808A1 true EP1284808A1 (fr) 2003-02-26
EP1284808A4 EP1284808A4 (fr) 2003-07-02

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EP01923390A Withdrawn EP1284808A4 (fr) 2000-04-14 2001-04-17 Separation de micromolecules

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EP (1) EP1284808A4 (fr)
JP (1) JP2003531286A (fr)
CA (1) CA2405027A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003088394A (ja) * 2001-09-19 2003-03-25 Ehime Prefecture 有機物分解物の製造方法及び製造装置
KR102348198B1 (ko) * 2019-12-06 2022-01-10 주식회사 바이오에프디엔씨 미코스포린-유사 아미노산인 포피라334 대량생산을 위한 정제방법

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3870617A (en) * 1971-03-30 1975-03-11 Rhone Poulenc Sa Apparatus for forced flow electrophoresis
US3989613A (en) * 1973-05-16 1976-11-02 The Dow Chemical Company Continuous balanced flow fixed boundary electrophoresis
GB2118975A (en) * 1982-02-26 1983-11-09 Hideyuki Nishizawa Method and apparatus for continuously separating high molecular weight amphoteric electrolytes by electrophoresis

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3870617A (en) * 1971-03-30 1975-03-11 Rhone Poulenc Sa Apparatus for forced flow electrophoresis
US3989613A (en) * 1973-05-16 1976-11-02 The Dow Chemical Company Continuous balanced flow fixed boundary electrophoresis
GB2118975A (en) * 1982-02-26 1983-11-09 Hideyuki Nishizawa Method and apparatus for continuously separating high molecular weight amphoteric electrolytes by electrophoresis

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO0178876A1 *

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Publication number Publication date
JP2003531286A (ja) 2003-10-21
CA2405027A1 (fr) 2001-10-25
EP1284808A4 (fr) 2003-07-02

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