Miniaturised Biosensor with Optimized Amperometric Detection
First Claim
1. :
- An amperometric detection method for determining the presence, the amount and/or the concentration of an analyte in a microfluidic sensor comprising the steps of;
a) providing a microfluidic sensor comprising at least one microstructure including at least one working electrode integrated with precise size and location in one wall portion of said microstructure, the height of said microstructure above said integrated working electrode being at least twice the characteristic length—
or the radius in the case of a circular electrode—
r of said integrated working electrode;
b) filling said microfluidic sensor with the sample to analyse;
c) applying the potential required to directly or indirectly detect said analyte by amperometry for a time period shorter than the ratio r2/D, where r is in metres and D is the diffusion coefficient of said analyte in m2/s, and measuring the resulting oxidation or reduction current at said integrated working electrode during this time period, so that only the analyte molecules submitted to a hemi-spherical or hemi-cylindrical diffusion regime above said at least one integrated working electrode are probed during the amperometric measurement;
and optionallyd) performing sequential amperometric measurements by repeating step c) after a relaxation time longer than half of the ratio r2/D.
2 Assignments
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Accused Products
Abstract
A method to optimize the amperometric detection in a microsystem consists in limiting the detection to times when the diffusion layer (18-20) of the analyte to detect remains smaller than the microchannel (7) height. The charge detected during the second part of the amperometric measurement (which corresponds to the integral of the measured current over the corresponding time period) can also be considered so as to remove the contribution of the capacitive current and, when applicable, of the current resulting from the reduction or oxidation of the analyte molecules present in a recess above the electrode at the beginning of the detection. A microfluidic amperometric sensor for performing the method comprises at least one microchannel (7) having at least one electrode (15-17), integrated in one wall of the microchannel, and having a characteristic length or radius which is smaller than half the microchannel height.
56 Citations
73 Claims
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1. :
- An amperometric detection method for determining the presence, the amount and/or the concentration of an analyte in a microfluidic sensor comprising the steps of;
a) providing a microfluidic sensor comprising at least one microstructure including at least one working electrode integrated with precise size and location in one wall portion of said microstructure, the height of said microstructure above said integrated working electrode being at least twice the characteristic length—
or the radius in the case of a circular electrode—
r of said integrated working electrode;b) filling said microfluidic sensor with the sample to analyse; c) applying the potential required to directly or indirectly detect said analyte by amperometry for a time period shorter than the ratio r2/D, where r is in metres and D is the diffusion coefficient of said analyte in m2/s, and measuring the resulting oxidation or reduction current at said integrated working electrode during this time period, so that only the analyte molecules submitted to a hemi-spherical or hemi-cylindrical diffusion regime above said at least one integrated working electrode are probed during the amperometric measurement; and optionally d) performing sequential amperometric measurements by repeating step c) after a relaxation time longer than half of the ratio r2/D. - View Dependent Claims (5, 6, 7, 8, 9, 11, 13, 14, 15, 16, 69)
- An amperometric detection method for determining the presence, the amount and/or the concentration of an analyte in a microfluidic sensor comprising the steps of;
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2. :
- An amperometric detection method for determining the presence, the amount and/or the concentration of an analyte in a microfluidic sensor comprising the steps of;
a) providing a microfluidic sensor comprising at least one microstructure including at least one working electrode integrated with precise size and location in one wall portion of said microstructure, the height of said microstructure above said integrated working electrode being at least twice the characteristic length—
or the radius in the case of a circular electrode—
r in metres of said integrated working electrode, and said microstructure exhibiting a recess of height L in metres above said at least one integrated working electrode;b) filling said microfluidic sensor with the sample to analyse; c) applying the potential required to directly or indirectly detect said analyte by amperometry for a time period shorter than the ratio (r+L)2/D, where D is the diffusion coefficient of said analyte in m2/s, and measuring the resulting oxidation or reduction current at said integrated working electrode during this time period, so that only the analyte molecules submitted to a hemi-spherical or hemi-cylindrical diffusion regime within said microstructure are probed during the amperometric measurement; and optionally d) performing sequential amperometric measurements by repeating step c) after a relaxation time longer than half of the ratio (r+L)2/D. - View Dependent Claims (4, 10)
- An amperometric detection method for determining the presence, the amount and/or the concentration of an analyte in a microfluidic sensor comprising the steps of;
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3. (canceled)
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12. (canceled)
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17-19. -19. (canceled)
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20. :
- An amperometric microfluidic sensor comprising at least one microstructure including;
a. at least one working electrode integrated with precise size and location in one wall portion of said microstructure, the height of said microstructure above said integrated working electrode being at least twice the characteristic length—
or the radius in the case of a circular electrode—
r of said integrated working electrode, and, optionally, said microstructure exhibiting a recess of length L in metres above said at least one integrated electrode,b. at least one counter electrode or one pseudo-reference electrode integrated in one wall portion of said microstructure, characterised in that the distance between said at least one counter electrode or one pseudo-reference electrode and said at least one working electrode is smaller than twice the microstructure height, said amperometric microfluidic sensor being adapted to detect signals resulting only from the analyte molecules submitted to a hemi-spherical or hemi-cylindrical diffusion regime above said at least one integrated working electrode upon application of the potential required to directly or indirectly detect said analyte by amperometry for a time period shorter than the ratio (r+L)2/D where D is the diffusion coefficient of said analyte in m2/s, and measuring the resulting oxidation or reduction current at said integrated working electrode during this time period. - View Dependent Claims (22, 35, 39, 44, 45, 46, 73)
- An amperometric microfluidic sensor comprising at least one microstructure including;
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21. (canceled)
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23-34. -34. (canceled)
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36-38. -38. (canceled)
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40-43. -43. (canceled)
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47-51. -51. (canceled)
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52. :
- A method of fabricating an amperometric microfluidic sensor comprising
a. at least one microstructure including at least one working electrode integrated with precise size and location in one wall portion of said microstructure, the height of said microstructure above said integrated working electrode being at least twice the characteristic length—
or the radius in the case of a circular electrode—
r of said integrated working electrode, and, optionally, said microstructure exhibiting a recess of height L in metres above said at least one integrated electrode,b. at least one counter electrode or one pseudo-reference electrode integrated in one wall portion of said microstructure, characterised in that the distance between said at least one counter electrode or one pseudo-reference electrode and said at least one working electrode is smaller than twice the microstructure height, said amperometric microfluidic sensor being adapted to detect signals resulting only from the analyte molecules submitted to a hemi-spherical or hemi-cylindrical diffusion regime above said at least one integrated working electrode upon application of the potential required to directly or indirectly detect said analyte by amperometry for a time period shorter than the ratio (r+L)2/D, where D is the diffusion coefficient of said analyte in m2/s, and measuring the resulting oxidation or reduction current at said integrated working electrode during this time period. - View Dependent Claims (55)
- A method of fabricating an amperometric microfluidic sensor comprising
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53-54. -54. (canceled)
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56-68. -68. (canceled)
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70-72. -72. (canceled)
Specification