Electrostatic device and method for immunological detection
First Claim
1. A process for the detection of an analyte contained in a fluid or a liquid, by reaction with a specific ligand to form a complex, the analyte or the ligand or both being carriers of neutralized electric charges, or opposite charges when the complex is formed, said process comprising:
- causing said fluid or liquid to migrate, after contact with the specific ligand, into a first porous electrically inert material interposed between opposite surfaces of a first pair of electrically charged electrodes of the same polarities, and detecting in the liquid having migrated into the porous material between the two electrodes, said analyte, ligand or complex, which have not been captured by the electrodes.
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Abstract
The invention concerns a device and a method for ultrasensitive detection comprising an electrically inert porous sheet sandwiched between two positively charged fine electrodes. The invention uses the capacity of the electrodes, resulting from their powerful electrostatic properties, for sensing marked antibody complexes related to antigens detected in the sample, and to leave marked antibodies non-complexed with said antigens free. The method consists in depositing a sample droplet on the porous material sheet upstream of the electrodes and in detecting downstream of the electrodes, in a signal-zone, the possible presence of an antigen-antibody complex which has diffused in the porous material. The invention is useful for detecting some millipicogrammes of antigen per milliliter of sample.
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Citations
28 Claims
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1. A process for the detection of an analyte contained in a fluid or a liquid, by reaction with a specific ligand to form a complex, the analyte or the ligand or both being carriers of neutralized electric charges, or opposite charges when the complex is formed, said process comprising:
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causing said fluid or liquid to migrate, after contact with the specific ligand, into a first porous electrically inert material interposed between opposite surfaces of a first pair of electrically charged electrodes of the same polarities, and detecting in the liquid having migrated into the porous material between the two electrodes, said analyte, ligand or complex, which have not been captured by the electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
the first porous material interposed between a preceding pair of electrodes, further comprises an extension beyond said first electrodes, said liquid or fluid is caused to pass between a second pair of electrodes supplied on opposite zones of said extension of the first porous material, the electrodes or this second pair being charged and of identical polarities to each other, but of a sign opposite to that of the polarities of the electrodes of the first pair, and the detection is carried out upstream of the second pair of electrodes, after which the ligand has migrated into said first porous material first through the first pair and then through the second pair of electrodes for semiquantitative determinations.
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9. The process according to claim 8, wherein the first pair of electrodes is calibrated so as to trap a maximum predetermined quantity of analyte in the form of analyte-ligand complex, and their is detected downstream of the second pair of electrodes an excess of analyte.
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10. The process according to claim 7, wherein the analyte carries electrical charges, wherein the fluid or liquid containing the analyte is introduced into the region of the deposited ligand, to form of the complex, thereafter a separate dose of the analyte is introduced into the region, wherein the second dose of the analyte is marked, and the presence of marked analyte is detected in the liquid having migrated between the electrodes.
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11. The process according to claim 9, wherein the analyte is constituted by a predetermined antigen, the ligand by a specific antibody of the antigen, and the electrodes of the first pair of electrodes have a negative polarity.
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12. The process according to claim 11, wherein the first pair of electrodes is calibrated to trap a quantity of an analyte ligand complex, the quantity of trapped antigen cannot exceed that corresponding to its normal content in the original liquid, or fluid, wherein the fluid is a biological fluid from a healthy subject, and the detection is only of the excess antigen relative to the normal content of antigen present in the original fluid or liquid.
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13. The process according to claim 12, further comprising a step of detecting an excess in blood plasma of D-Dimer.
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14. The process according to claim 1, wherein the analyte is an antibody, the ligand an antigen.
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15. The process according to claim 14, wherein the polarities of the first pair of electrodes are of opposite sign to those of the antibodies.
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16. The process according to claim 1, wherein the analyte is deposited in a region determined by the first porous material upstream of the electrodes, said region not permitting the retention of a dose of analyte exceeding a predetermined threshold value, a volume of solution containing an electrically charged ligand is deposited in said region whose polarity is opposite that of the electrodes, and the analyte ligand complex in the liquid having migrated between the two electrodes is detected such that the quantity of analyte initially deposited on said region will exceed the dose defined by the predetermined threshold value.
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17. The process according to claim 16, wherein the analyte is an antigen and the region or predetermined regions of the porous material are coated with quantities of antibodies responsible for said threshold values.
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18. A device for the detection of an analyte contained in a fluid or liquid by reaction with a specific ligand of the analyte to form a complex, the analyte or the ligand or the two being carriers of neutralized electric charges or opposite charges when the complex is formed, said device comprising:
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at least one pair of electrodes provided with surfaces which face each other and are electrically charged, with identical polarities;
an electrically inert porous material, interposed between the surfaces and permitting diffusion, between said electrodes, of the liquid to be deposited in a free zone of said porous material, upstream of a liquid path of migration in said porous material; and
means associated with said porous material for the detection in the liquid migrated into the porous material, between said electrodes, said analyte, ligand or complexes, which have not been captured by the electrodes. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification