RU2713587C1 - Biosensor, resistant to coffee stain effect - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: invention discloses a biosensor which is resistant to the effect of a coffee stain. Biosensor includes substrate; at least one working electrode and at least one comparison electrode, respectively, structured on one surface of the substrate by conductive material; a reagent layer having a material which causes an electrochemical reaction with the target biomaterial and is deposited on a predetermined area of one substrate surface, on which a working electrode and a reference electrode are structured, such that a portion of the reagent layer is located on the portion of the working electrode, and another part of reagent layer is located on part of comparison electrode; and a film layer located on one surface of the substrate, on which the working electrode and the comparison electrode are structured, wherein the film layer has a slot extending with a predetermined width such that the reagent layer is exposed therethrough. Each of the working electrode and the comparison electrode includes an output part located in the external area of the slot; a reaction portion located in the inner region of the slot and extending with a predetermined width in the width direction of the slot to a predetermined length such that both longitudinal outputs of the reaction portion are separated by a predetermined interval from the side walls of the slot which face each other in the width direction of the slot; and connection part having smaller width than reaction part, and extending from reaction part to connection with outlet part.

EFFECT: invention provides increase in the measurements accuracy.

6 cl, 11 dwg

Description

FIELD OF TECHNOLOGY

[1] This application claims priority to Korean Patent Application No. 10-2017-0137669, filed October 23, 2017 in the Republic of Korea, the disclosure of which is incorporated herein by reference.

[2] The present disclosure relates to an electrochemical biosensor, and more specifically, to a biosensor that is resistant to the coffee stain effect that occurs when a reagent that causes an electrochemical reaction with the target biomaterial covers the biosensor electrode.

BACKGROUND OF THE INVENTION

[3] Typically, an electrochemical biosensor is a device that emits an electrical signal in accordance with an electrochemical reaction between the biomaterial used and the reagent, by using an electrode coated with a biological specificity reagent, such as an enzyme, antigen, antibody, hormone or the like . That is, an electrochemical biosensor provides specific information about a biomaterial, such as a current value or a voltage value. Since the biosensor has recently been used in blood glucose measurement systems or in various systems of accurate medical diagnostics, there is growing interest and demand for methods to increase the accuracy and reproducibility of the values measured by the biosensor.

[4] However, as disclosed in Korean Unexamined Patent Publication No. 10-2004-0028437 and Korean Unexamined Patent Publication No. 10-2014-0005156, an existing method for fixing a reagent for an electrochemical reaction with a target biomaterial to a biosensor electrode requires a process for applying a liquid reagent to the electrode and drying the liquid reagent during the actual manufacturing process. For this reason, due to the effect of the coffee stain that occurs during drying, the reagent particles are unevenly displaced along the edge of the reagent application area, and the number and density of displaced particles also differ for each biosensor. This impairs the accuracy and reproducibility of the values measured using the biosensor and does not guarantee the reliability of the measured values.

DISCLOSURE

Technical problem

[5] The present disclosure is intended to provide a biosensor that can improve the accuracy and reproducibility of values measured using a biosensor and ensure the reliability of the measured values, despite the coffee stain effect and manufacturing tolerances caused by the actual biosensor manufacturing process.

Technical solution

[6] In one aspect of the present disclosure, a coffee spot-resistant biosensor is provided, comprising: a substrate; at least one working electrode and at least one reference electrode, respectively structured on one surface of the substrate with a conductive material; a reagent layer having an electrochemical reaction with the target biomaterial and deposited on a predetermined area of one substrate surface on which the working electrode and the reference electrode are structured, so that part of the reagent layer is located on the part of the working electrode, and the other part of the reagent layer is located on the part of the electrode comparisons and a film layer located on one surface of the substrate on which the working electrode and the reference electrode are structured, the film layer having a slit extending with a predetermined width so that the reagent layer is exposed through it, each of the working electrode and the reference electrode includes : lead part located in the outer region of the gap; a reaction part located in the internal region of the gap and extending with a predetermined width in the direction along the width of the gap to a predetermined length such that both longitudinal leads of the reaction part are separated by a predetermined interval from the side walls of the gap, which face each other in the direction along the width of the gap; and a connecting part having a smaller width than the reaction part, and extending from the reaction part to the connection with the output part.

[7] In an embodiment, assuming that the gap width is Ws and the interval between the longitudinal terminal of the reaction portion that faces the side wall of the gap and the side wall is d, the biosensor may be configured to satisfy Equation 1 below.

[8] [Equation 1]

[9] 0.075Ws ≤ d ≤ 0.2Ws

[10] In an embodiment, assuming that the width of the reaction portion is Wr and the width of the connecting portion is Wc and the side wall is d, the biosensor may be configured to satisfy Equation 2 below.

[11] [Equation 2]

[12] 0.2Wr ≤ Wc ≤ 0.5Wr

[13] In an embodiment, each of the working electrode and the reference electrode may further include a protruding part that has the same width as the connecting part and extends from the reaction part so that the output of the protruding part is located in the outer region of the gap, and the connecting part and the protruding part can extend from the reaction part along the direction along the width of the gap in opposite directions, respectively.

[14] In an embodiment, assuming that the slot width is Ws and the length of the protruding portion is Le, the biosensor may be configured to satisfy Equation 3 below.

[15] [Equation 3]

[16] 0.2Ws <Le ≤ 0.4Ws

[17] In an embodiment, the slot width may be in the range of 1.5 mm to 3 mm.

Beneficial effects

[18] According to the present disclosure, the reaction portion of the electrode coated with the reagent and located in the region of the slit of the biosensor into which the target biomaterial is inserted is separated from the side walls of the slit by a predetermined interval without coming into contact with the edge of the reagent located near the side walls of the slit. Thus, it is possible to increase the accuracy and reproducibility of the values measured using the biosensor and to ensure the reliability of the measured values, despite the effect of the coffee stain, under the influence of which the reagent particles are unevenly displaced along the edge of the reagent deposited on the electrode.

[19] Also, since the connecting part extends in the direction along the width of the slit from the reaction part of the electrode and is connected to the lead part of the electrode, a protruding part extending in the direction opposite to the connecting part from the reaction part of the electrode is also provided, as a result of which its output is located in the outer region the gap, it is possible to maintain the area of the electrode constantly located in the inner region of the gap, even when a tolerance occurs in the direction along the width of the gap while the film layer having the gap and placed on a substrate, with a further increase in the accuracy and reproducibility of the values measured using the biosensor.

[20] In addition, with regard to the structural relationship between the slit and the electrode of the biosensor and the structural relationship between the reaction part, the connecting part and the protruding part of the electrode, an optimized range of numerical values is provided, which is suitable for maintaining the reproducibility of the values measured using the biosensor at a high level, without using new material or substance, thereby contributing to the design of the biosensor and reducing the time and cost required for the manufacture of the biosensor.

[21] Further, it should be readily apparent to those skilled in the art that various technical problems not mentioned here can be solved by various embodiments according to the present disclosure.

DESCRIPTION OF DRAWINGS

[22] FIG. 1 is a perspective view showing a coffee stain resistant biosensor according to an embodiment of the present disclosure.

[23] FIG. 2 is an exploded perspective view showing the biosensor of FIG. 1.

[24] FIG. 3 is a schematic view showing the structure of a biosensor electrode according to an embodiment of the present disclosure.

[25] FIG. 4 is a schematic view showing a reagent layer deposited on an electrode having a common structure.

[26] FIG. 5 is a schematic view showing a reagent layer deposited on a biosensor electrode according to an embodiment of the present disclosure.

[27] FIG. 6 is a schematic view showing an example where a film layer is located on a substrate on which an electrode having no protruding portion is structured.

[28] FIG. 7 is a schematic view showing another example where a film layer is located on a substrate on which an electrode having no protruding portion is structured.

[29] FIG. 8 is a schematic view showing an example where the film layer is located on a substrate on which an electrode having a protruding portion is structured.

[30] FIG. 9 is a schematic view showing another example where a film layer is located on a substrate on which an electrode having a protruding portion is structured.

[31] FIG. 10 is a graph showing a coefficient of variability of a biosensor according to an interval between a side wall of a slit and a reaction portion of an electrode.

[32] FIG. 11 is a graph showing a coefficient of variability of the biosensor according to the width of the connecting portion of the electrode.

BEST MODE FOR CARRYING OUT THE INVENTION

[33] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings in order to clarify a solution to the technical problem of the present disclosure. However, when clarifying the present disclosure, explanations of the related technologies will be omitted if, due to such explanations, the essence of the present disclosure becomes unclear. In addition, the terms used in this application are defined taking into account the functions in this disclosure, and they can be replaced, depending on the intention or order of the designer, manufacturer, etc. Therefore, the definitions of the terms described below can be given based on the contents of this entire application.

[34] FIG. 1 is a perspective view showing a coffee stain-resistant biosensor 100 according to an embodiment of the present disclosure.

[35] As shown in FIG. 1, a biosensor 100 according to an embodiment of the present disclosure includes a substrate 110, electrodes 120, 130, a reagent layer 140, a film layer 150, etc., and in some embodiments, may further include an outer film layer 160. The biosensor 100 may have a laminated structure in which electrodes 120, 130, a reagent layer 140, a film layer 150, an outer film layer 160, etc. located on one surface of the substrate 110.

[36] Located on the substrate 110, the film layer 150 has a slit 152 into which the target biomaterial to be analyzed is introduced. In addition, in the outer film layer 160 located on the film layer 150, an outlet 162 may be formed to release air from the inside of the slit 152 as the target biomaterial is introduced into the slit 152. A reagent layer 140 containing an electrochemical reaction with the target biomaterial located on the part of the substrate corresponding to the inner region of the slit 152, among the entire substrate 110.

[37] In this case, the term “biomaterial” used in this application includes all types of biomaterials whose properties can be quantified by applying amperometry among electrochemical methods. For example, the target biomaterial may be biological material, such as blood, saliva, a cell and a gene, biochemical material, or material derived from a biomaterial or biochemical material.

[38] FIG. 2 is an exploded perspective view showing the biosensor 100 of FIG. 1.

[39] As shown in FIG. 2, the substrate 110 corresponds to the base layer of the biosensor 100 and can be made of insulating material. At least one working electrode 120 and at least one reference electrode 130 are structured on one surface of the substrate 110 with a conductive material. For example, the working electrode 120 and the reference electrode 130 can be formed on the same surface of the substrate 110 using a screen printing process using carbon ink.

[40] The reagent layer 140 includes a material that causes an electrochemical reaction with the target biomaterial and is applied to a predetermined area on one surface of the structured substrate 110 on which the working electrode 120 and the reference electrode 130 are structured, so that part of the reagent layer 140 is located on the part a working electrode 120, and another part thereof is located on a part of the reference electrode 130.

[41] The film layer 150 is located on one surface of the substrate 110 on which the working electrode 120 and the reference electrode 130 are structured, and has a slit 152 extending with a predetermined width so that the reagent layer 140 is exposed through it. In this case, the slot 152 may be a U-shaped groove having an opening at the edge of the film layer 150 and recessed to the center of the film layer 150 with a predetermined width based on the horizontal section of the film layer 150. The lamination order of the reagent layer 140 and the film layer 150 can be suitably changed depending on the embodiments.

[42] The outer film layer 160 is located on the film layer 150 to protect the interior of the slit 152 where the reagent layer 140 is located. An outlet 162 formed in the outer film layer 160 may be formed in a position in communication with the outlet of the slit 152 so that air from the inside of the slit 152 exits when the target biomaterial is introduced into the inner space of the slit 152 due to a capillary phenomenon or the like. The outer layer 160 of the film may be made of a hydrophilic material. If the outer layer 160 of the film is made of a hydrophilic material, it is easier to introduce the target biomaterial containing moisture.

[43] A measuring system for measuring the characteristics of the target biomaterial by using the biosensor 100 described above can quantitatively measure the characteristics of the target biomaterial through the use of amperometry, among various electrochemical methods. That is, the measuring system can give quantitative measurements of the target biomaterial by applying a given voltage to the working electrode 120 of the biosensor 100 and measuring the value of the redox current generated in the biosensor 100, depending on the concentration or content of the target biomaterial introduced into the biosensor 100.

[44] For example, if the biosensor 100 is configured as a glucose sensor used in a blood glucose measurement system, then the reagent layer 140 may be made of a reagent in which an enzyme such as GOx (glucose oxidase) or GDH (glucose dehydrogenase) is mixed that reacts with glucose contained in the blood, and an electron transfer mediator, restored by taking an electron when the enzyme reacts. In this case, the reagent may include an enzyme, such as GOx or GDH, which performs the function of supplying electrons to the mediator by reaction with glucose, at a concentration of 1000-5000 U / ml, and may include a ferricyanide, ruthenium or osmium compound, which acts as a mediator of electron transfer between the enzyme and the working electrode 120, in the range of 100-500 mm. In addition, the reagent may include 0.1-10 wt.% BSA (bovine serum albumin), which supports the activity of the enzyme, 0.1-2 wt.% Surfactant, such as Triton X-100 or Tween-20, which promotes good spreading of the liquid reagent along the electrodes 120, 130, and 0.1-1 wt.% a fixing agent, such as PEG (polyethylene glycol), PVP (polyvinylpyrrolidone) or agarose, which helps fix the reagent.

[45] The blood glucose measurement system using the biosensor 100 described above does not measure blood glucose by directly measuring the electrons generated during the reaction of glucose and an enzyme in the biosensor 100, but by measuring the amount of redox current that occurs when the mediator electron transfer, restored by receiving the corresponding electrons, is oxidized again, namely, the magnitude of the current exiting through the working electrode 120 of the biosensor 100.

[46] In this case, the value of current i (t) over time at the biosensor in which amperometry is used can be calculated using the following Cottrell equation.

[47] [Cottrell equation]

[48] i (t) = (nFAD ^1/2 C ₀ ) / (πt) ^1/2

[49] In the Cottrell equation, n is the number of electrons involved in the electrochemical reaction, F is the Faraday constant, A is the electrode area, D is the diffusion coefficient, C ₀ is the initial concentration of the material (reduced mediator), π is the circular constant, and t is time.

[50] As shown in the Cottrell equation, the biosensor current is determined by taking, as factors, the number (n) of electrons involved in the reaction and the area (A) of the electrode. Thus, in order to increase the accuracy and reproducibility of the values measured using the biosensor, it is necessary to prevent the edges of the reagent layer 140 from participating in the electrochemical reaction, where the reagent particles are unpredictably displaced due to the coffee stain effect, and also to keep the electrode area used for the electrochemical reaction constant.

[51] For this purpose, the working electrode 120 and the reference electrode 130 of the biosensor 100 according to an embodiment of the present disclosure may include, respectively, lead portions 122, 132, reaction portions 124, 134 and connection portions 126, 136, and may further include protruding portions 128, 138, depending on the embodiments.

[52] The lead-out portions 122, 132 are located in the outer region of the slit 152 formed in the film layer 150 located on the substrate 110 and are configured to electrically connect them to an external circuit. The shapes of the lead portions 122, 132 can be changed in various ways.

[53] The reaction portions 124, 134 are located in the interior of the slit 152 and extend with a predetermined width to a predetermined length in the direction along the width of the slit 152 so that both longitudinal leads of the reaction portions 124, 134 are spaced a predetermined interval from the side walls of the slit 152, which facing each other in the direction along the width of the slit 152.

[54] The connecting parts 126, 136 are narrower than the reaction parts 124, 134, and extend from the reaction parts 124, 134 to the connection with the lead parts 122, 132. In this case, one end of the connecting parts 126, 136 is located in the inner region slots 152, and the other end of the connecting parts 126, 136 is located in the outer region of the slit 152.

[55] If the working electrode 120 and the comparison electrode 130 further include protruding parts 128, 138, respectively, these protruding parts 128, 138 have the same width as the connecting parts 126, 136, and extend from the reaction parts 124 so that their conclusions are located in the outer region of the gap 152. In this case, the connecting parts 126, 136 and the protruding parts 128, 138 are made extending along the direction along the width of the gap 152 from the reaction parts 124, 134, respectively, in opposite directions.

[56] FIG. 3 is a schematic view showing the structure of an electrode of a biosensor 100 according to an embodiment of the present disclosure.

[57] As shown in FIG. 3, the reaction parts 124, 134 of the electrodes 120, 130 are located in the inner region of the gap 152 and extend with a predetermined width to a predetermined length in the direction along the width of the gap 152 so that both longitudinal leads of the reaction parts 124, 134 are separated from the side walls of the gap 152, which facing each other in the direction along the width of the slit 152, at regular intervals d1, d2.

[58] In this case, the intervals d1, d2 between the reaction parts 124, 134 and the side walls of the slit 152 are set within the range in which the edges of the reagent layer 140, which are applied to the inner region of the slit 152 and dried, are not in direct contact with the reaction parts 124, 134, but the area of the reaction parts 124, 134 is not seriously reduced. For this purpose, the interval between the longitudinal terminals of the reaction parts 124, 134, which are facing the side walls of the slit 152, and the corresponding side walls can be determined in a range that satisfies the Equation 1 below.

[59] [Equation 1]

[60] 0.075Ws ≤ d ≤ 0.2Ws [mm]

[61] In equation 1, Ws is the width of the slit 152, and d is the interval between the longitudinal leads of the reaction parts 124, 134 facing the side walls of the slit 152, and the corresponding side walls. In this case, the width (Ws) of the slit 152 may range from 1.5 mm to 3 mm.

[62] FIG. 3, d1 and d2, respectively, are in the range from 0.075Ws to 0.2Ws. If d1 and d2 are less than 0.075Ws, the edges of the reagent layer 140 that are unevenly displaced due to the coffee stain effect can come into contact with the reaction parts 124, 134, participating in the redox reaction with the target biomaterial, thereby impairing the reproducibility of using a biosensor of 100 values. Also, if d1 and d2 are more than 0.2 Ws, the areas of the reaction parts 124, 134 are greatly reduced, decreasing the output current of the biosensor 100, which also impairs the accuracy of the values measured using the biosensor 100.

[63] As mentioned above, the connecting parts 126, 136 of the electrodes 120, 130 are made extending from the reaction parts 124, 134 with a smaller width than the reaction parts 124, 134 connected respectively to the output parts 122, 132.

[64] In this case, the width (Wc) of the connecting parts 126, 136 should be determined in a range in which the contact area with the edge of the reagent layer 140 is minimized, and this allows easy implementation without causing disconnection. For this, the width (Wc) of the connecting parts 126, 136 can be determined in a range that satisfies the Equation 2 below.

[65] [Equation 2]

[66] 0.2Wr ≤ Wc ≤ 0.5Wr [mm]

[67] In equation 2, Wr is the width of the reaction parts 124, 134, and Wc is the width of the connecting parts 126, 136. In this case, the width of the reaction part 124 of the working electrode 120 may be from 0.2 mm to 3 mm, and the width of the reaction part 134 of the reference electrode 130 may be from 0.2 mm to 4.5 mm.

[68] FIG. 3, the width (Wc) of the connecting portion 126 has a size in the range of 0.2Wr to 0.5Wr. If the width (Wc) of the connecting part 126 is less than 0.2 Wr, the actual implementation is difficult and a manufacturing defect or detachment is possible. Also, if the width (Wc) of the connecting part 126 is more than 0.5 Wr, the contact area between the edge of the reagent layer 140 and the connecting part 126 is increased, thereby impairing the reproducibility of the values measured using the biosensor 100.

[69] Moreover, if the working electrode 120 and the comparison electrode 130 further include protruding parts 128, 138 extending in opposite directions to the connecting parts 126, 136 respectively from the reaction parts 124, 134, these protruding parts 128, 138 may have the same width as the connecting parts 126, 136.

[70] FIG. 4 is a schematic view showing a reagent layer 16 deposited on electrodes 12, 14 having a common structure.

[71] As shown in FIG. 4, if the reagent solution deposited on the electrodes 12, 14 having the general structure formed on the substrate 10 is dried to form a reagent layer 16, the reagent particles are unevenly displaced along the edge of the reagent layer 16 due to the effect of the coffee stain, and the amount and density of the displaced particles are different for each biosensor. Since the areas (x1-x4) of the electrodes 12, 14 having a common structure have a large area in contact with the edges of the reagent layer 16, the edges of the reagent layer 16 participate in the electrochemical reaction and the redox reaction with the target biomaterial at a significant percentage, which worsens the accuracy and reproducibility of the values measured using the biosensor, thereby not guaranteeing the reliability of the measured values.

[72] FIG. 5 is a schematic view showing a biosensor reagent layer 140 applied to the electrodes 120, 130 according to an embodiment of the present disclosure.

[73] As shown in FIG. 5, in the present disclosure, although the reagent particles deposited on the substrate 110 are not uniformly displaced along the edges of the reagent layer 140 due to the coffee stain effect, since the regions (y1-y4) of the connecting parts 126, 136 and the protruding parts 128, 138 are in contact with the edges of the reagent layer 140 have a small area, mainly in the redox reaction with the target biomaterial the center of the reagent layer 140 is in contact with the reaction parts 124, 134 of the electrodes 120, 130, and the edges of the reagent layer 140 are involved in a very low degree, which does not affect on the measured values. Thus, according to the present disclosure, it is possible to increase the accuracy and reproducibility of the values measured using biosensors, and to guarantee the reliability of the measured values.

[74] Turning again to FIG. 3, a working electrode 120 and a reference electrode 130 structured on a biosensor substrate 110 according to an embodiment of the present disclosure may further include protruding portions 128, 138, which respectively have the same width as the connecting portions 126, 136, and extend from the reaction parts 124, 134 so that their conclusions are located in the outer region of the gap 152. In this case, the connecting parts 126, 136 and the protruding parts 128, 138 can extend from the reaction parts 124, 134 along the direction along the width of the gap 152, respectively opposite directions.

[75] The protruding portions 128, 138 are attached to the electrodes 120, 130 of the biosensor 100 in order to maintain a constant electrode area located in the inner region of the slit 152, even when tolerance occurs in the width direction (Ws) of the slit 152, while having the slit 152 film layer 150 is placed on the substrate 110, thereby further increasing the accuracy and reproducibility of the values measured using the biosensor.

[76] For this, the length (Le) of the protruding portions 128, 138 can be determined to satisfy a range according to Equation 3 below.

[77] [Equation 3]

[78] 0.2Ws <Le ≤ 0.4Ws [mm]

[79] In equation 3, Ws is the slit width 152, and Le is the length of the protruding parts 128, 138.

[80] In order to maintain a constant electrode area located in the inner region of the gap 152, the protruding portions 128, 138 must have a field of a given length (l ₀ ) in the outer region of the gap 152, even if a tolerance is formed in the direction along the width of the gap 152 (Ws) while the film layer 150 is placed on the substrate 110. Thus, the length (Le) of the protruding portions 128, 138 should be at least greater than 0.2Ws, i.e. maximum value d1 or d2. Also, since the tolerance when laminating the film layer 150 is permissible only when the reaction parts 124, 134 of the electrodes 120, 130 are located in the inner region of the slit 152, the length (Le) of the protruding parts 128, 138 should not be more than 0.4Ws, i.e. . maximum value d1 + d2.

[81] Meanwhile, in FIG. 3, the connecting part 126 of the working electrode 120 should be shorter than its protruding part 128, and should be longer than the protruding part 138 of the comparison electrode 130. Also, the connecting portion 136 of the reference electrode 130 should also be formed no shorter than its protruding portion 138.

[82] FIG. 6 is a schematic view showing an example where the film layer 150a is located on a substrate 110a on which an electrode 120a having no protruding portion is structured.

[83] FIG. 7 is a schematic view showing another example where the film layer 150a is located on a substrate 110a on which an electrode 120 having no protruding portion is structured.

[84] If a tolerance is formed on the left while the film layer 150a is placed on the substrate 110a on which the electrode 120a having only the lead-out portion 122a, the reaction portion 124a, and the connecting portion 126a are structured, as shown in FIG. 6, the area (Sa) of the connecting portion 126a located in the inner region of the slit of the film layer 150 is narrowed, thereby reducing the electrode area used for the electrochemical reaction.

[85] Meanwhile, if the tolerance is formed on the right while the film layer 150a is placed on the substrate 110a on which the electrode 120a is structured having only the lead portion 122a, the reaction portion 124a and the connecting portion 126a, as shown in FIG. 7, the area (Sa ') of the connecting portion 126a located in the internal region of the slit of the film layer 150 is expanded, thereby increasing the electrode area used for the electrochemical reaction.

[86] As described above, if the biosensor electrode does not include the protruding portion described above, the area of the electrode used in the electrochemical reaction varies with the biosensors due to the tolerance created in the manufacture of the biosensor.

[87] FIG. 8 is a schematic view showing an example where the film layer 150 is located on a substrate 110 on which an electrode 120 having a protruding portion is structured.

[88] FIG. 9 is a schematic view showing another example where the film layer 150 is located on a substrate 110 on which an electrode 120 having a protruding portion is structured.

[89] If a tolerance is formed on the left while the film layer 150 is placed on the substrate 110 on which the electrode 120 is structured, having an output portion 122, a reaction portion 124, a connecting portion 126 and a protruding portion 128, as shown in FIG. 8, the area (S2) of the connecting portion 126 located in the inner region of the gap of the film layer 150 is narrowed, but the area (S1) of the protruding portion 128 located in the inner region of the gap of the film layer 150 is expanded. Since the connecting part 126 and the protruding part 128 have the same width, the electrode area used in the electrochemical reaction is kept constant, despite tolerances.

[90] In addition, if the tolerance is formed on the right while the film layer 150 is placed on the substrate 110 on which the electrode 120 is structured, having an output portion 122, a reaction portion 124, a connecting portion 126 and a protruding portion 128, as shown in FIG. . 9, the area (S2 ') of the connecting portion 126 located in the inner region of the slit of the film layer 150 is expanded, but the area (S1') of the protruding portion 128 located in the inner region of the slit of the film layer 150 is narrowed. Since the connecting part 126 and the protruding part 128 have the same width, the electrode area used in the electrochemical reaction is kept constant, despite tolerances.

[91] As described above, if the biosensor electrode includes the protruding portion described above, the electrode area used in the electrochemical reaction is kept constant for all biosensors, despite the tolerance created by the biosensor manufacturing, thereby guaranteeing a high level of reproducibility of the values measured using biosensors.

[92] Next, the effect of increasing the reproducibility of the biosensor according to an embodiment of the present disclosure will be tested with reference to the experimental results of measurements of the coefficient of variability.

[93] The coefficient of variation indicates the standard deviation of the population consisting of blood glucose values measured by the biosensor as a percentage of the average value of this population. The smaller the deviation, the higher the reproducibility.

[94] In the experiment on measuring the coefficient of variation, biosensors having a generally structure according to FIG. 2 and performed using blood glucose sensors, and hypoglycemic blood with a blood glucose of 119 mg / dl and hyperglycemic blood with a blood glucose of 299 mg / dl were used as target biomaterials.

[95] FIG. 10 is a graph showing a coefficient of variability of a biosensor as a function of the interval between the side wall of the slit and the reaction portion of the electrode. In the experiment with reference to FIG. 10 blood glucose was measured 30 times for hypoglycemic blood with a blood glucose of 119 mg / dl and 20 times for hyperglycemic blood with a blood glucose of 299 mg / dl, while maintaining a constant width (Ws) of the reaction part and changing the length of the reaction parts of the electrode for each biosensor.

[96] As shown in FIG. 10, if the intervals d1, d2 between the side walls of the gap and the reaction part of the electrode increase more than 0.05Ws relative to the width (Ws) of the gap, the coefficient of variability (CV) of the measured values can be less than 4% not only for hyperglycemic blood, but also for hypoglycemic blood, thus demonstrating a high level of reproducibility. In particular, if the intervals d1, d2 fall within the range from 0.075Ws to 0.2Ws relative to the width (Ws) of the slit 152, then the coefficient of variation is less than 3%, and it should be understood that a relatively higher reproducibility is manifested. . However, if the intervals d1, d2 increase more than 0.2Ws, the area of the reaction part of the electrode is excessively reduced, which rather impairs reproducibility.

[97] FIG. 11 is a graph showing a coefficient of variability of a biosensor as a function of the width of an electrode connecting portion. In the experiment with reference to FIG. 11, blood glucose was measured 30 times for hypoglycemic blood with a blood glucose of 119 mg / dl and 20 times for hyperglycemic blood with a blood glucose of 299 mg / dl, while maintaining a constant width (Wr) of the reaction part and changing the width ( Wc) the connecting part and the protruding part of the electrode for each biosensor.

[98] As shown in FIG. 11, if the width (Wc) of the connecting part and the protruding part decreases less than 0.5 Wr relative to the width (Wr) of the reaction part, then the coefficient of variation of the measured values is less than 4%, not only for hyperglycemic blood, but also for hypoglycemic blood, thus demonstrating high reproducibility. However, if the width (Wc) of the connecting part and the protruding part decreases below 0.2 Wr, the actual implementation is difficult, and this may cause poor manufacture and disconnection.

[99] As described above, according to the present disclosure, the reaction portion of the electrode coated with the reagent and located in the region of the slit of the biosensor into which the target biomaterial is introduced is separated from the side walls of the slit by a predetermined interval so as not to come into contact with the edge of the reagent located near the side walls cracks. Thus, it is possible to increase the accuracy and reproducibility of the values measured using the biosensor, as well as to ensure the reliability of the measured values, despite the effect of the coffee stain, in which the reagent particles are unevenly displaced along the edge of the reagent deposited on the electrode.

[100] Also, since the connecting portion extends in a direction along the width of the slit from the reaction portion of the electrode and is connected to the lead portion of the electrode, a protruding portion extending in the direction opposite to the connecting portion from the reaction portion of the electrode is also provided, so that its lead is located in the outer region the gap, it is possible to maintain a constant electrode area located in the inner region of the gap, even when a tolerance occurs in the direction along the width of the gap, while the layer of film commoners on the substrate, with additional thereby increasing the accuracy and reproducibility of the measured values using the biosensor.

[101] In addition, with regard to the structural relationship between the gap and the electrode of the biosensor and the structural relationship between the reaction part, the connecting part and the protruding part of the electrode, an optimized range of numerical values is proposed, which is suitable for maintaining the reproducibility of the values measured using the biosensor at a high level, without using new material or substance, thus contributing to the design of the biosensor and reducing the time and cost required for the manufacture of the biosensor.

[102] Further, it will be readily apparent to those skilled in the art that various technical problems not mentioned here can be solved by various embodiments according to the present disclosure.

[103] Prior to this, the present disclosure has been described with reference to specific embodiments. However, it will be readily apparent to those skilled in the art that various modifications may be implemented within the technical scope of the present disclosure. Therefore, the above embodiments should be considered not restrictively, but illustratively. That is, the scope of the present disclosure is defined in the attached claims, and all differences within the scope of its equivalents should be considered included in the present disclosure.

Claims (26)

1. Resistant to the effect of a coffee stain biosensor containing: a substrate; at least one working electrode and at least one reference electrode, respectively structured on one surface of the substrate with a conductive material; a reagent layer having an material causing an electrochemical reaction with the target biomaterial and deposited on a predetermined area of said one surface of the substrate on which the working electrode and the reference electrode are structured, so that part of the reagent layer is located on the part of the working electrode, and the other part of the reagent layer is located on the part reference electrode; and a film layer located on said one surface of the substrate on which the working electrode and the reference electrode are structured, the film layer having a slit extending with a predetermined width so that the reagent layer is exposed through it, wherein each of the working electrode and the reference electrode includes: lead part located in the outer region of the gap; a reaction part located in the internal region of the gap and extending with a predetermined width in the direction along the width of the gap to a predetermined length such that both longitudinal leads of the reaction part are separated by a predetermined interval from the side walls of the gap, which face each other in the direction along the width of the gap; and a connecting part having a smaller width than the reaction part, and extending from the reaction part to the connection with the output part. 2. Resistant to the effect of a coffee stain biosensor according to claim 1, in which, assuming that the gap width is Ws and the interval between the longitudinal terminal of the reaction portion, which faces the side wall of the gap, and the side wall is d, the following Equation 1 is satisfied. [Equation 1] 0.075Ws ≤ d ≤ 0.2Ws 3. Resistant to the effect of a coffee stain biosensor according to claim 1, in which, assuming that the width of the reaction part is Wr and the width of the connecting part is Wc, the following Equation 2 is satisfied. [Equation 2] 0.2Wr ≤ Wc ≤ 0.5Wr 4. Resistant to the effect of a coffee stain biosensor according to claim 1, in which each of the working electrode and the reference electrode further includes a protruding part, which has the same width as the connecting part, and extends from the reaction part so that the output of the protruding part is located in the outer region of the gap, and while the connecting part and the protruding part extend from the reaction part along the direction along the width of the gap in opposite directions, respectively. 5. Resistant to the effect of a coffee stain biosensor according to claim 4, in which, assuming that the gap width is Ws and the length of the protruding part is Le, the following Equation 3 is satisfied. [Equation 3] 0.2Ws <Le ≤ 0.4Ws 6. Resistant to the effect of a coffee stain biosensor according to claim 1, in which the gap width is in the range from 1.5 mm to 3 mm.

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