1. Field of the Invention
The present invention relates to an electrochemical test strip, and in particular relates to an electrochemical test strip with an underfill detection function.
2. Description of the Related Art
Referring to
However, the conventional electrochemical test strip requires at least two pins for the additional set of identifying electrodes, thus reducing the number of available pins and obstructing the expansion for other functions.
Further more, a conventional electrode structure comprises a reaction area between an upper electrode and a lower electrode (face to face structure) for determining the hematocrit ratio by flowing speed. When the sample contacts the reagent in the reaction area, the electronic signal between the upper and lower electroedes starts to highly increase by the chemical reaction between the sample and the reagent, when the sample contacts electrode without reagent, the electronic signal starts to highly decrease, and the time interval between the highly increasing and decreasing times of the electronic signal can be used to calculate flowing speed and the hematocrit ratio of the sample. However, the electrodes of the face to face structure could be conducted to each other by compressing the strip, and the flowing speed could be affected by the coating of the reagent on the reaction area.
The present invention provides an electrochemical test strip, comprising a substrate, an electrode structure, and an insulative layer. The substrate comprises a test end. The electrode structure is formed on the substrate, comprising: a first electrode and a second electrode. The second electrode comprises a first end, a second end, an extension portion and a bent portion, wherein the extension portion is connected between the first end and the bent portion, the bent portion is connected to the second end, and the extension portion and the first electrode define a space therebetween for receiving the bent portion. The insulative layer covers at least a part of the electrode structure and forms an opening, wherein a sample is injected through the opening into the electrochemical test strip and sequentially contacts the first electrode and the second electrode.
The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
a is a schematic view showing a substrate and an electrode structure of an electrochemical test strip according to another embodiment of the invention;
b is a schematic view showing a substrate and an electrode structure of an electrochemical test strip according to another embodiment of the invention;
c is a schematic view showing a substrate and an electrode structure of an electrochemical test strip according to another embodiment of the invention;
d is a schematic view showing a substrate and an electrode structure of an electrochemical test strip according to another embodiment of the invention;
e is a schematic view showing a substrate and an electrode structure of an electrochemical test strip according to another embodiment of the invention;
a is a schematic view showing a sample injection direction of an electrochemical test strip according to another embodiment of the invention;
b is a schematic view showing a sample injection direction of an electrochemical test strip according to another embodiment of the invention;
a is a schematic view showing variation of electronic signals with different hematocrit (HCT) ratios of samples;
b is a schematic view showing variation of an electronic signal between second and third electrodes according to a testing voltage;
a and 8b are flowcharts of an embodiment of the method for testing a sample by an electrochemical test strip; and
a and 9b are sectional schematic views showing an electrode structure of an electrochemical test strip for testing a sample.
Referring to
Referring to
The bent portion 137 in
The detection process will be described below. First, the first end 123 and the second end 125 are provided with a small voltage. A sample (such as blood) can be injected through the opening 141 into the reaction area 142 and sequentially move through the working electrode 129, the first section 132, and the second section 134 along an injection direction B.
In some embodiments, the electrochemical test strip can be used for determining the hematocrit ratio of a sample. As shown in
As shown in
Specifically, when the current signal has a slope exceeding a predetermined value due to the sample flowing through the second electrode 220 to the third electrode 230, a second time T2 is recorded (step S16). The hematocrit value of the sample can be calculated according to the time period T from the first time T1 to the second time T2, wherein T=T2−T1 (steps S17˜S18).
Fill or underfill of the sample in the reaction area 142 may be also determined according to the difference between the current signal and the background current value (step 19). If the difference between the current signal and the background current value exceeds a threshold value, the instrument may change to apply a third testing voltage between the first electrode 210 and the second electrode 220 for measuring the glucose concentration of the sample, and the glucose concentration can also be calibrated by the hematocrit value (step 20). Otherwise, the instrument may further prompt the user to change the electrochemical test strip if the difference between the background current value and the current signal is less than a threshold value (step 21).
Referring to
Referring to
Referring to
In this embodiment, the comb-shaped structure C has right angled teeth. In some embodiments, the comb-shaped structure C may have rounded or acute angled teeth. The traces of the comb-shaped structure C may have a width, ranging from 0.1 to 1 mm. However, the traces may also respectively have different widths, to provide different densities thereof. Furthermore, the comb-shaped structure C may also have a spacing width between the traces, ranging from 0.1 to 1 mm. However, the comb-shaped structure C may respectively have different spacing widths between the traces, to provide different densities thereof. In some embodiments, the comb-shaped structure C can be produced by various kinds of processes, such as screen printing, laser ablation, sputtering, or electroless plating processes, but is not limited thereto.
The underfill of the sample may also be detected by using different protruding sections, thus preventing erroneous detections. Referring to
Specifically, the shape of the protruding section 135 is not only limited to
In some embodiments, the opening 141 and the injection direction B are not perpendicular to the test end 143. As shown in
In some embodiments, the electrochemical test strip may further comprises a metal layer between the electrode structure 120 and the substrate 110, wherein the metal layer may include gold, silver, palladium, platinum, nickel, copper, molybdenum, cobalt, chromium, zinc, tin, plumbum, or titanium.
In some embodiments, the working electrode 129, the first section 132, and the second section 134 of the electrochemical test strip (
The invention provides an electrochemical test strip comprising an auxiliary electrode with a bent portion to increase the resistance thereof. As the electrochemical test strip does not require different materials to produce electrodes (the electrode structure can be produced by the same material), the cost thereof can be effectively reduced.
While the disclosure has been described by way of example and in terms of the preferred embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
This application claims the benefit of U.S. Provisional Application No. 61/586,907, filed on Jan. 16, 2012, the entirety of which is incorporated by reference.
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Number | Date | Country | |
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20130180869 A1 | Jul 2013 | US |
Number | Date | Country | |
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61586907 | Jan 2012 | US |