EP0356187A2
Expired / Lapsed
EP
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Electrophoresis using contour-clamped electric fields
Assignee: Leland Stanford Junior University
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Filing: 1989-08-21
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Granted: —
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Expires: 2009-08-21
Abstract
Abstract A gel electrophoresis method and apparatus is described in which the shape and orientation of the electric field is controlled by contour clamping. Electrodes are arranged around a closed contour. Two or more electrodes, the driving electrodes, are clamped at a potential difference φ₀ to establish the general orientation and strength of the electric field. The remaining electrodes are clamped to intermediate potentials to control the shape of the field established by the driving electrodes. The field is varied in accordance with the purpose of the electrophoresis, depending upon the size of the particles and the information to be determined concerning the particles.
Inventors
- 👤 Gilbert Chu
- 👤 Douglas Vollrath
- 👤 Ron Davis
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 22:10
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/416; G01N27/447; G01N27/44704; G01N27/44713; G01N27/44756; G01N27/44773
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
110 words
An apparatus for electrophoretic separation of a sample using an electric field comprising: a support for a gel medium in which the sample can be placed; a plurality of electrodes substantially equally spaced on the sides of a polygon around said gel medium; means for clamping at least one pair (1,16...) of electrodes to a driving potential difference between them across the medium, there being resistance means (R₁) connecting adjacent electrodes, the resistance of of the resistance means (R₁,R₂₅) between electrodes (4,5) next to at least one of the corners of the polygon being a fraction (e.g. one-half) of the resistance of the resistance means (R₁) between the remaining electrodes.
Claim 2
Independent Claim
110 words
An apparatus for electrophoretic separation of a sample using an electric field comprising: a support for a gel medium in which the sample can be placed; a plurality of electrodes substantially equally spaced on the sides of a polygon around said gel medium; means for clamping at least one pair (1,16...) of electrodes to a driving potential difference between them across the medium, there being resistance means (R₁) connecting adjacent electrodes, the resistance of of the resistance means (R₁,R₂₅) between electrodes (4,5) next to at least one of the corners of the polygon being a fraction (e.g. one-half) of the resistance of the resistance means (R₁) between the remaining electrodes.
Claim 3
Dependent Claim
41 words
An apparatus according to claim 1 wherein the fraction is the ratio of the perpendicular distance between adjacent electrodes (4,5) next to the corner of the polygon to the equal spacing between the other electrodes on the sides of the polygon.
Claim 4
Dependent Claim
17 words
An apparatus according to claim 1 or claim 2 wherein the fraction and the ratio are one-half.
Claim 5
Independent Claim
38 words
An apparatus according to any one of the preceding claims wherein said means for clamping the field-shaping electrodes further comprises voltage buffer means connected between adjacent electrodes on the closed contour which acts to stabilise the field-shaping potentials.
Claim 6
Dependent Claim
66 words
An apparatus according to claim 4, wherein the voltage buffer means comprises a plurality of buffer circuits, each associated with one of the electrodes, and each buffer means having an input for receiving an input reference voltage from a resistance means associated with a respective electrode; an output connected to the respective electrode, and one or more transistors driving the output in response to the input.
Claim 7
Independent Claim
24 words
An apparatus according to any one of the preceding claims wherein means are provided for alternating the electric field between at least two orientations.
Claim 8
Dependent Claim
14 words
An apparatus according to claim 6 wherein the means for alternating comprise switch means.
Claim 9
Dependent Claim
17 words
An apparatus according to claim 7 wherein the switch means comprises a mechanical or solid state relay.
Claim 10
Dependent Claim
17 words
An apparatus according to claim 8 wherein the switch means further comprises one or more switching diodes.
Claim 11
Independent Claim
24 words
An apparatus according to any one of the preceding claims wherein the electrodes are arranged around a polygon being a square, rectangle or hexagon.
Claim 12
Independent Claim
70 words
An apparatus according to any one of the preceding claims wherein one of a plurality of pairs of electrodes (1,16;9,24...) may be selectively switched to a driving potential difference, the resistance means between the electrodes next to the corners adjacent said selected pair of electrodes being selectively shunted by shunt means (R₂₅,D₅;R₂₆,D₈), thereby to render the resistance of said selected resistance means equal to said fraction of said remaining electrodes.
Claim 13
Dependent Claim
367 words
12 An apparatus for electrophoretic separation and detection of a sample using an electric field, comprising: a support for a gel medium in which the sample can be placed; a plurality of electrodes arranged along a closed contour around said gel medium, comprising: a first set of one or more driving electrodes; a second set of one or more driving electrodes; a third set of one or more shaping electrodes located between said first and second sets of driving electrodes on a first side of the periphery of said closed contour, and containing one or more externally driven shaping electrodes; a fourth set of one or more shaping electrodes located between said first and second sets of driving electrodes on a second side of the periphery; opposite said first side of the periphery of said closed contour, and containing one or more externally driven shaping electrodes; means for clamping said first set of driving electrodes to a first potential; means for clamping said second set of driving electrodes to a second potential, the difference between said first and second potentials serving as a driving potential to establish the general orientation and strength of said electric field within said enclosed contour; means for clamping said one or more externally driven shaping electrodes of said third set of shaping electrodes to a first shaping potential intermediate between said first and second potentials; means for clamping the remaining shaping electrodes of said third set of shaping electrodes to potentials intermediate said first driving potential and said first shaping potential or intermediate said second driving potential and said first shaping potential; means for clamping said one or more externally driven shaping electrodes of said fourth set of shaping electrodes to a first shaping potential intermediate between said first and second potentials; means for clamping the remaining shaping electrodes of said fourth set of shaping electrodes to potentials intermediate said first driving potential and said second shaping potential or intermediate said second driving potential and said second shaping potential; the said clamping means including resistors between the electrodes, and the resistance between electrodes next to corners of the closed contour having a resistance about half that of resistances between other adjacent electrodes.
Claim 14
Dependent Claim
367 words
12 An apparatus for electrophoretic separation and detection of a sample using an electric field, comprising: a support for a gel medium in which the sample can be placed; a plurality of electrodes arranged along a closed contour around said gel medium, comprising: a first set of one or more driving electrodes; a second set of one or more driving electrodes; a third set of one or more shaping electrodes located between said first and second sets of driving electrodes on a first side of the periphery of said closed contour, and containing one or more externally driven shaping electrodes; a fourth set of one or more shaping electrodes located between said first and second sets of driving electrodes on a second side of the periphery; opposite said first side of the periphery of said closed contour, and containing one or more externally driven shaping electrodes; means for clamping said first set of driving electrodes to a first potential; means for clamping said second set of driving electrodes to a second potential, the difference between said first and second potentials serving as a driving potential to establish the general orientation and strength of said electric field within said enclosed contour; means for clamping said one or more externally driven shaping electrodes of said third set of shaping electrodes to a first shaping potential intermediate between said first and second potentials; means for clamping the remaining shaping electrodes of said third set of shaping electrodes to potentials intermediate said first driving potential and said first shaping potential or intermediate said second driving potential and said first shaping potential; means for clamping said one or more externally driven shaping electrodes of said fourth set of shaping electrodes to a first shaping potential intermediate between said first and second potentials; means for clamping the remaining shaping electrodes of said fourth set of shaping electrodes to potentials intermediate said first driving potential and said second shaping potential or intermediate said second driving potential and said second shaping potential; the said clamping means including resistors between the electrodes, and the resistance between electrodes next to corners of the closed contour having a resistance about half that of resistances between other adjacent electrodes.
Claim 15
Dependent Claim
19 words
An apparatus according to claim 12 which further comprises buffer circuit means connected between said resistors and said electrodes.
Claim 16
Dependent Claim
70 words
An apparatus according to claim 13 wherein said buffer circuit means comprises a plurality of buffer circuits, each associated with one of said electrodes, each said buffer circuit comprising: an input terminal for receiving an input reference voltage from an associated one of said resistors; an output terminal connected to said associated electrode; and means for providing said clamping voltage to said electrode in response to said input reference voltage.
References Cited (Backward Citations)
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