Abstract:
An electrode reaction area testing method of biosensor test strip includes: (1) preparing a semi-finished or finished test strip product having at least one sensing window corresponding to an electrode reaction area; a plural electrodes exposed from the electrode reaction area; (2) detecting the electrode reaction current of the electrode reaction area to obtain a first electrode reaction current and a third electrode reaction current; (3) calculating a current ratio of the first electrode reaction current to the third electrode reaction current; (4) determining the current ratio; (5) completing the detection of the electrode reaction area to determine whether the semi-finished or finished test strip product is good or defective, so as to test the accuracy of the separating plate attaching position or the insulating position and the applicability of the electrode reaction area in the manufacture of the test strip.

Description:
FIELD OF THE INVENTION 
       [0001]    The presented invention relates to a testing method of a biosensor test strip, and more particularly to an electrode reaction area testing method of a biosensor test strip that tests the accuracy of an attaching position or an insulating position of a separating plate in the manufacture of the biosensor test strip, so that an electrode reaction area of the biosensor test strip can be controlled within a fixed conduction operation range. 
       BACKGROUND OF THE INVENTION 
       [0002]    Nowadays, people pay more attention to individual physical health, particularly to chronic diseases caused by high blood sugar, high pressure, and high cholesterol, and to establish a habit of preventing, caring and treating these diseases in daily life, thus it common for people to measure physiological data for the prevention and treatment purposes. In present ways of measuring physiological data, a biological test strip is used for carrying a sample, and a testing device (such as a blood glucose meter) is used for testing the glucose concentration or cholesterol concentration of the sample through an electrochemical sensor system. The system generally tests the analyte in the sample by an enzymatic amperometric method, which a oxidation voltage is applied on the strip for generating an electrochemical current (or a sensing current), so as to generate the so-called Cottrell current. The concentration of the analyte in the same is calculated according to the Cottrell equation. In the Cottrell equation i(t)=K·n·F·A·C·D 0.5 ·t −0.5  where i is the instantaneous value of a sensing current; K is a constant; n is the number of transmitted electrons; F is the Faraday constant; A is the surface area of an electrode; C is the concentration of an analyte in a sample; D is the diffusion coefficient of a reagent; and t is a specific time after applying a predetermined voltage to an electrode. 
         [0003]    The conventional test strip includes a substrate and a separating plate, and a plurality of electrodes disposed on the substrate, where the separating plate is attached on and includes a sensing window. The separating plate is cover onto the plurality of electrodes on the substrate, and the electrodes are exposed from the sensing window. When a sample is introduced into the sensing window, and the testing instrument is turned on to generate an electronic signal and produce a test result. 
         [0004]    When the separating plate is attached onto the substrate, the area of the plurality of electrodes exposed from the sensing window is an electrode reaction area provided for carrying the sample, but the exposed electrode reaction area may have a deviation issue when attaching the separating plate. In other words, a detective product with the electrode reaction area incompliant with the required testing standards may be produced, such as the problems of the electrode reaction area as reflected in the Cottrell equation which cause errors in the biological test data. There is no testing method for testing whether the separating plate attaching position is correct, whether the electrode reaction area is complaint with the required standards, or whether the electrode reaction area falls within the scope of a good product so far, and thus the prior art causes troubles while using or testing the product and requires improvements. Therefore, it is an important research and development subject for related manufacturers to overcome the drawbacks and problems of unable to control the reacting electrode area of a test strip when the test strip is manufactured. 
         [0005]    In view of the drawbacks with regard to the manufacture and application of the conventional test strip and the fact of unable to control the testing of the electrode reaction area of the conventional test strip, the inventor of the presented invention conducted extensive researches and developed a test strip, which the electrode reaction area can be tested easily to control and provide an electrode reaction area testing method of the biosensor test strip in accordance with the present invention to control and improve the quality of the product. 
       SUMMARY OF THE INVENTION 
       [0006]    Therefore, it is a primary objective of the present invention to provide an electrode reaction area testing method of a biosensor test strip, such that when the test strip is manufactured and tested, the accuracy of the separating plate attaching position or insulating position, and the applicability of the electrode reaction area can be tested to determine whether the manufacture of the test strip falls within the range of a good product, so as to improve the quality of the test strip product and the accuracy of measuring the physiological data. 
         [0007]    To achieve the aforementioned objectives, the present invention provides an electrode reaction area testing method of a biosensor test strip comprising the following steps: 
         [0008]    1. Prepare a semi-finished or finished test strip product, wherein the semi-finished or finished test strip product comprises a substrate and a separating plate; the separating plate has a sensing window; the substrate has a first electrode, a second electrode and a third electrode disposed on a side of the sensing window and sequentially arranged from the outside to the inside; an end of the first electrode proximate to the sensing window is a first reacting electrode, an end of the second electrode proximate to the sensing window is a second reacting electrode, an end of the third electrode proximate to the sensing window is a third reacting electrode. 
         [0009]    2. Cover the separating plate onto the first electrode, the second electrode and the third electrode, aligning the sensing window with the first reacting electrode, the second reacting electrode, and the third reacting electrode, wherein the first reacting electrode, the second reacting electrode and the third reacting electrode have a partial area exposed from the sensing window; this partial area of the first reacting electrode exposed from the sensing window is a first electrode reaction area, the partial area of the second reacting electrode exposed from the sensing window is a second electrode reaction area, and the partial area of the third reacting electrode exposed from the sensing window is a third electrode reaction area. 
         [0010]    3. Introduce a sample into the semi-finished or finished test strip product, and apply a voltage, such that the first electrode reaction area generates a first electrode reaction current, and the third electrode reaction area generates a third electrode reaction current; detect and obtain the first electrode reaction current and the third electrode reaction current. 
         [0011]    4. Calculate a current ratio of the first electrode reaction current to the third electrode reaction current. 
         [0012]    5. Determine the current ratio by determining whether the current ratio falls within a predetermined numeric value range. If yes, then the electrode reaction area of the semi-finished or finished test strip product is good, or else the electrode reaction area of the semi-finished or finished test strip product is defective. 
         [0013]    6. Complete the test of the electrode reaction area of the semi-finished or finished test strip product to determine whether the test strip is a good product or a defective product. 
         [0014]    In the aforementioned testing method, the predetermined numeric value range is set by experiment statistics such that when the current ratio falls within the numeric value range, the first electrode reaction area and the third electrode reaction area are correct. 
         [0015]    The presented invention will become clearer in light of the following detailed description of an illustrative embodiment of this invention described in connection with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is an exploded view of a biosensor test strip of the present invention; 
           [0017]      FIG. 2  is a perspective view of a biosensor test strip of the present invention; 
           [0018]      FIG. 3  is a top view of a semi-finished product of a biosensor test strip of the present invention; 
           [0019]      FIG. 3A  is a partial blow-up view of a semi-finished product of a biosensor test strip of the present invention; 
           [0020]      FIG. 3B-3E  are schematic views of inspecting a defective product by different methods respectively; 
           [0021]      FIG. 4  is a first flow chart of a testing method of a biosensor test strip of the present invention; and 
           [0022]      FIG. 5  is a second flow chart of a testing method of a biosensor test strip of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    With reference to  FIGS. 1 and 2  for the manufactured and assembled structure of a biosensor test strip of the present invention, the biosensor test strip as shown in  FIG. 1  comprises a test strip  90 ; the test strip  90  comprises a substrate  91 , a separating plate  95  and a cover plate  96 ; the separating plate  95  has a sensing window  951 ; the substrate  91  has three electrodes disposed thereon, the three electrodes proximate to a side of the sensing window, and the three electrodes sequentially arranged from the outside to the inside are a first electrode  92 , a second electrode  93  and a third electrode  94 ; an end of the first electrode proximate to the sensing window is a first reacting electrode  921 , an end of the second electrode proximate to the sensing window is a second reacting electrode  931 , an end of the third electrode proximate to the sensing window is a third reacting electrode  941 ; the first reacting electrode  921 , the second reacting electrode  931  and the third reacting electrode  941  form an electrode reaction area  25  ( FIG. 3A ); the other end of each electrode corresponsive to the electrode reaction area  25  is a first sensing electrode  922 , a second sensing electrode  932 , and a third sensing electrode  942 ; the separating plate  95  is attached onto the substrate  91  and covered onto the first electrode  92 , the second electrode  93  and the third electrode  94 , wherein the sensing window  951  is aligned with the first reacting electrode  921 , the second reacting electrode  931  and the third reacting electrode  941 ; the length of the separating plate  95  allows the separating plate  95  to be exposed from the first sensing electrode  922 , the second sensing electrode  932 , or the third sensing electrode  942  when the separating plate  95  is attached onto the substrate  91 ; the cover plate  96  is covered onto the separating plate  95 , the length of the cover plate  96  is equal to the length of the separating plate  95 , the cover plate  96  has a guide opening  971  formed at a position corresponsive to the sensing window  951 . When use, the test strip  90  is inserted into a testing instrument (such as a blood glucose meter, not shown in the figure), and then a sample (such as a blood or urine sample) is introduced through the guide opening  971 , and then the sample is in contact with the first reacting electrode  921 , the second reacting electrode  931  and the third reacting electrode  941 , and the testing instrument is turned on to generate an electronic signal and produce a test result. 
         [0024]    With reference to  FIGS. 3 and 3A , after the separating plate  95  is attached onto the substrate  91 , the first reacting electrode  921 , the second reacting electrode  931  and the third reacting electrode  941  have a partial area exposed from the sensing window  951 ; the partial area of the first reacting electrode  921  exposed from the sensing window  951  is a first electrode reaction area  921 A, the partial area of the second reacting electrode  931  exposed from the sensing window  951  is a second electrode reaction area  931 A; the partial area of the third reacting electrode  941  exposed from the sensing window  951  is a third electrode reaction area  941 A; the area exposed from first electrode reaction area  921 A, the second electrode reaction area  931 A and the third electrode reaction area  941 A is a redox reaction area; the first electrode reaction area  921 A and the third electrode reaction area  941 A serve as a basis for testing the electrode reaction area of the present invention. 
         [0025]    When the test strip  90  is used, the first electrode reaction area  921 A ( FIG. 3A ), the second electrode reaction area  931 A and the third electrode reaction area  941 A carry the sample (or an object to be tested). According to the Cottrell equation, i(t)=K·n·F·A·C·D 0.5 ·t −0.5 , and the concentration C of the sample (or object to be tested) is directly proportional to the sensing current i, since the sensing current i is also directly proportional to the surface area A of the operating electrode, the surface area A of the operating electrode of an accurately defined test strip is a key factor to a precise measuring instruction. Taking the blood glucose test strip for example, we introduce the sample into the test strip  90  and apply a voltage, such that the first electrode reaction area  921 A generates a first electrode reaction current  921 C (not shown in the figure), and the third electrode reaction area  941 A generates a third electrode reaction current  941 C (not shown in the figure). Assumed that the first electrode reaction area  921 A is A 1 , the first electrode reaction current  921 C is C 1 , the third electrode reaction area  941 A is A 3 , and the third electrode reaction current  941 C is C 3 , the area ratio of the first electrode reaction area A 1  to the third electrode reaction area A 3  is equal to the first electrode reaction current C 1  to the third electrode reaction current C 3  (A 1 /A 3 =C 1 /C 3 =R). Through experiment statistics, a numeric value range is set in advance, such that when the value of R falls within the numeric value range, the first electrode reaction area  921 A and the third electrode reaction area  941 A are correct, and the attaching position of the separating plate  95  is correct, and the electrode reaction area of the test strip  90  is good product. On the other hand, when the value of R does not fall within the numeric value range, the first electrode reaction area  921 A and the third electrode reaction area  941 A are incorrect, and the attaching position of the separating plate  95  is incorrect, so that the electrode reaction area of the test strip is defective. The settings of aforementioned numeric value range varies with the type of samples, different biological test strips or different testing precision requirements. 
         [0026]    With reference to  FIG. 3B to 3E , if the attaching position of the separating plate  95  is incorrect, the first electrode reaction area  921 A and the third electrode reaction area  941 A displayed from the sensing window  951  will be changed, so that the value of R of A 1 /A 3 =C 1 /C 3  will be changed and will not fall within the predetermined numeric value range, so that the electrode reaction area of the test strip is determined to be defective and incompliant with the precision requirement of the electrode area. The testing method of the invention allows us to discover the defective electrode reaction area of the test strip in advance to prevent the defective test strip product from being manufactured continuously, entering into the market, or generating a wrong testing value in a test or adjustment immediately in a test. 
         [0027]    With reference to  FIG. 4  and the aforementioned description of the electrode reaction area testing method of a biosensor test strip electrode in accordance with the present invention, the method comprises the following steps: 
         [0028]    S 1 : Prepare a semi-finished or finished test strip product, wherein the semi-finished or finished test strip product comprises a substrate  91  and a separating plate  95 , wherein the separating plate  95  has a sensing window  951 , the substrate  91  has a first electrode  92 , a second electrode  93  and a third electrode  94  disposed on a side of the sensing window  951  and sequentially arranged from the outside to the inside; an end of the first electrode  92  proximate to the sensing window  951  is a first reacting electrode  921 , an end of the second electrode  93  proximate to the sensing window  951  is a second reacting electrode  931 , an end of the third electrode  94  proximate to the sensing window  951  is a third reacting electrode  941 . 
         [0029]    S 2 : Cover the separating plate  95  onto the first electrode  92 , the second electrode  93  and the third electrode  94 , align the sensing window  951  with the first reacting electrode  921 , the second reacting electrode  931  and the third reacting electrode  941 , wherein each of the first reacting electrode  921 , the second reacting electrode  931  and the third reacting electrode  941  has a partial area exposed from the sensing window  951 ; the partial area of the first reacting electrode  921  exposed from the sensing window  951  is a first electrode reaction area  921 A, the partial area of the second reacting electrode  931  exposed from the sensing window  951  is a second electrode reaction area  931 A, the partial area of the third reacting electrode  941  exposed from the sensing window  951  is a third electrode reaction area  941 A. 
         [0030]    S 3 : Introduce a sample into the semi-finished or finished test strip product, and apply a voltage, such that the first electrode reaction area  921 A generates a first electrode reaction current  921 C, and the third electrode reaction area  941 A generates a third electrode reaction current  941 C. 
         [0031]    S 4 : Detect and obtain the first electrode reaction current  921 C and the third electrode reaction current  941 C, and then calculate a current ratio of the first electrode reaction current  921 C to the third electrode reaction current  941 C. 
         [0032]    S 5 : Determine whether the current ratio falls within a predetermined numeric value range; if yes, then the electrode reaction area of the semi-finished or finished test strip product is good and the separating plate  95  attaching position or insulating position is correct, or else the electrode reaction area of the semi-finished or finished test strip product is defective and the separating plate  95  attaching position or insulating position is incorrect. 
         [0033]    S 6 : Complete testing the electrode reaction area of the semi-finished or finished test strip product. to determine whether the test strip is a good product or a defective product. 
         [0034]    With reference to  FIG. 5  and the aforementioned description of the electrode reaction area testing method of a biosensor test strip in accordance with the present invention, the method comprises the following steps: 
         [0035]    S 41 : Prepare a semi-finished or finished test strip product, wherein the semi-finished or finished test strip product comprises at least one sensing window  951 ; the sensing window  951  is aligned with an electrode reaction area  25  ( FIG. 3A ), a plurality of electrodes is exposed from the electrode reaction area  25 ; the electrode reaction area  25  has a first reacting electrode  921 , a second reacting electrode  931 , a third reacting electrode  941  sequentially arranged from the outside to the inside; the partial area of the first reacting electrode  921  exposed from the sensing window  951  is a first electrode reaction area  921 A; the partial area of the second reacting electrode  931  exposed from the sensing window is a second electrode reaction area  931 A; the partial area of the third reacting electrode  941  exposed from the sensing window is a third electrode reaction area  941 A. 
         [0036]    S 42 : Introduce a sample into the semi-finished or finished test strip product, and apply a voltage such that the first electrode reaction area  921 A generates a first electrode reaction current  921 C, and the third electrode reaction area  941 A generates a third electrode reaction current  941 C, and then detect and obtain the first electrode reaction current  921 C and the third electrode reaction current  941 C. 
         [0037]    S 43 : Calculate a current ratio of the first electrode reaction current  921 C to the third electrode reaction current  941 C by dividing the first electrode reaction current  921 C by the third electrode reaction current  941 C to obtain the current ratio (wherein the current ratio=the area ratio= 921 C/ 941 C= 921 A/ 941 A). 
         [0038]    S 44 : Determine whether the current ratio falls within a predetermined numeric value range; if yes, then the electrode reaction area of the semi-finished or finished test strip product is good, or else the electrode reaction area of the semi-finished or finished test strip product is defective. Taking the blood glucose test strip for example, we determine whether the current ratio falls within a predetermined numeric value range; if yes, then the electrode reaction area of the semi-finished or finished test strip product is good, or else the electrode reaction area of the semi-finished or finished test strip product is defective, and such result ensures that the first electrode reaction area  921 A and the third electrode reaction area  941 A exposed from the sensing window  951  complies with the required standards. In other words, the separating plate attaching position or insulating position is correct. 
         [0039]    S 45 : Complete testing the electrode reaction area of the semi-finished or finished test strip product to determine whether the test strip is a good product or a defective product. 
         [0040]    In the electrode reaction area testing method of a biosensor test strip in accordance with the present invention, the accuracy of the separating plate attaching position or insulating position and the applicability of the electrode reaction area can be tested during the manufacture of the test strip to determine whether is test strip is a good product, so as to improve the quality of the test strip product and the accuracy of measuring physiological data.