Source: https://patents.justia.com/patent/20140308459
Timestamp: 2020-05-25 11:52:51
Document Index: 465422469

Matched Legal Cases: ['§371', 'Application No. 2000', 'Application No. 2000', 'Application No. 2000', 'Application No. 2000', 'Application No. 2000', 'arts 1102', 'arts 1102']

US Patent Application for BIOSENSOR, THIN FILM ELECTRODE FORMING METHOD, QUANTIFICATION APPARATUS, AND QUANTIFICATION METHOD Patent Application (Application #20140308459 issued October 16, 2014) - Justia Patents Search
Justia Patents Nonuniform Or Patterned CoatingUS Patent Application for BIOSENSOR, THIN FILM ELECTRODE FORMING METHOD, QUANTIFICATION APPARATUS, AND QUANTIFICATION METHOD Patent Application (Application #20140308459)
This application is a continuation of U.S. patent application Ser. No. 12/930,627, filed Jan. 11, 2011, which is a continuation of U.S. patent application Ser. No. 10/809,217, filed Mar. 25, 2004, now U.S. Pat. No. 7,998,325, which is a continuation of U.S. patent application Ser. No. 09/889,243, filed Oct. 1, 2001, now U.S. Pat. No. 6,875,327, which is a national stage entry under 35 U.S.C. §371 of PCT International Patent Application No. PCT/JP00/08012, filed Nov. 14, 2000, which claims priority of Japanese patent application Ser. No. 11/324,551, filed Nov. 15, 1999, Japanese Patent Application No. 2000/111255, filed Apr. 12, 2000, Japanese Patent Application No. 2000/113754, filed Apr. 14, 2000, Japanese Patent Application No. 2000/124394, filed Apr. 25, 2000, Japanese Patent Application No. 2000/128249, filed Apr. 27, 2000, and Japanese Patent Application No. 2000/130158, filed Apr. 28, 2000, the contents of all of which are hereby incorporated by reference into the subject application.
In the second process, a carbon paste is printed on the electrode lead parts 1102a and 1102b and dried to form a counter electrode 1203a and a working electrode 1103b. The working electrode 1103b is located inside the ring-shaped counter electrode 1103a, and the counter electrode 1103a and the working electrode 1103b is in contact with the electrode lead parts 1102a and 1102b, respectively.
In the third process, a insulating paste 1104 as an insulating material is printed on the counter electrode 1103a and the working electrode 13b and dried to define areas of the counter electrode 1103a and the working electrode 1103b.
The sample liquid (hereinafter, also referred to as “specimen”) is supplied to the inlet 1106b of the specimen supply path in a state where a fixed voltage is applied between the counter electrode 1103a and the working electrode 1103b by a quantification apparatus (hereinafter, also referred to as “measuring device”) connected to the biosensor Z. The specimen is drawn inside the specimen supply path by capillary phenomenon, passes on the counter electrode 1103a nearer to the inlet 1106b, and reaches to the working electrode 1103a, and a dissolution of the reagent layer 1105 is started. At this point of time, the quantification apparatus detects an electrical change occurring between the counter electrode 1103a and the working electrode 1103b, and starts a quantification operation. In this way, the substrate included in the sample liquid is quantified.
FIG. 2(a) is a schematic diagram illustrating how the electrodes of the above-described biosensor A are provided.
Here, the conductive layer 2 required for forming the electrode part is provided only on the internal surface of the support 1, and the conductive layer 2 is not provided on the internal surface of the cover 13. The electrode part provided on the internal surface of the support 1 is divided into the counter electrode 6, the working electrode 5 and the detecting electrode 7 by the slits 3a, 3b, 4a and 4b being provided.
On the other hand, a method is also conceivable which provides the conductive layer 2 not only on the internal surface of the support 1 but also on the internal surface of the cover 13. An example of this case will be described briefly with reference to FIGS. 2(b) and 2(c). FIG. 2(b) illustrates a case where the conductive layer 2 provided on the internal surface of the cover 13 is taken as the counter electrode 6 as it is, and the conductive layer 2 provided on the internal surface of the support 1 is taken as the working electrode 5 and the detecting electrode 7 by the slits 3a, 3b, 4a and 4b. Though the conductive layer 2 is provided on the whole internal surface of the support 1, there is no need to use an unnecessary part as an electrode. That is, the conductive layer 2 is provided on the whole internal surface of the support 1 because in a process for providing the conductive layer 2, it is easier to provide the conductive layer 2 on the whole surface than in the case where the conductive layer 2 is provided on a part of the internal surface of the support 1. A hatching indicating the conductive layer 2 on the whole of the internal surface of the support 1 is shown in the figure, but there is no need to use all of this as the electrode. FIG. 2(c) schematically illustrates a case where the counter electrode 6 is provided on the internal surface of the cover 13, and the working electrode 5 and the detecting electrode 7 are provided on the internal surface of the support 1 as in FIG. 2(b), while the way in which the slits are provided on the support 1 is different from that shown in FIG. 2(b). That is, in FIG. 2(c), the slit 4a is omitted as compared with FIG. 2(b), while in this case it is required that the area of the counter electrode 6 is equivalent to or larger than the area of the working electrode 5 in the specimen supply path. When the number of slits provided on the support 1 is decreased as described above, the manufacture can be made more easily. Further, since the working electrode 5 is located at a position opposed to the counter electrode 6 in FIG. 2(c), the length of the specimen supply path is decreased to reduce the size, thereby enabling a measurement based on a trace quantity of specimen.
Then, as shown in FIG. 3(c), for example in case of a blood sugar sensor, a reagent which is composed of glucose oxidase as enzyme, potassium ferricyanide as an electron transfer agent and the like is dripped and applied to the working electrode 25, the counter electrode 26, and the detecting electrode 27. Since the part where the reagent is applied is a position which is surrounded by the second slits 24a and 24b, the second slits 24a and 24b can be used as marks of a place where the reagent is applied. Further, since the applied reagent is a liquid, it spreads out in a circular form taking a point where the reagent is applied by dripping as a center, but the second slits 24a and 24b serve as breakwaters and define the position and area of the reagent layer 14 so that the reagent is prevented from spreading across the second slits 24a and 24b. Therefore, the reagent layer 14 is formed at a prescribed position in a prescribed area.
Next, as shown in FIG. 23, the slits 3103a, 3103b, 3103c and 3103d are formed by employing the laser in an area where each individual wafer Q of the electrical conductive layer 3102 formed on the support 3101 is formed, to divide the electrical conductive layer 3102 into the working electrode 3105, the counter electrode 3106, and the detecting electrode 3107, and the electrodes of plural biosensors X are formed in a row, thereby to form the sensor wafer P. Then, the electrodes of plural biosensors X which are formed in this process are cut on the cutting plane line 3110, and a reagent layer, a spacer and a cover (not shown here) are laminated on the electrodes of the biosensor X obtained by the cutting, thereby to form an individual biosensor.
FIG. 8(a) is a diagram illustrating states of the electrodes when the cutting position is deviated toward left from the cutting plane line 50. FIG. 8(b) is a diagram illustrating states of the electrodes when the cutting position is deviated toward right from the cutting plane line 50. In any of the cases where the cutting position is deviated toward right and left, the areas of the working electrode 45 and the counter electrode 46 are already defined by the first slits and the third slits, whereby as shown in FIG. 8, the areas of the working electrode 45 and the counter electrode 46 are equal to those when the cutting is performed on the cutting plane line 50 shown in FIG. 6(a), as long as the cutting is performed between the third slits 44a and 44b of the adjacent biosensors.
Numeral 61 denotes an insulating support composed of polyethylene terephthalate or the like. Numeral 62 denotes an electrical conductive layer which is formed on the whole surface of the support 61 and is composed of an electrical conductive material such as a noble metal, for example gold or palladium, and carbon. Numerals 63a, 63b, 63c and 63d denote first slits provided in the electrical conductive layer 62. Numerals 65, 66, and 67 denote electrodes which are formed by dividing the electrical conductive layer 62 by the first slits 63a, 63b, 63c and 63d, i.e., a working electrode, a counter electrode, and a detecting electrode as an electrode for confirming whether the specimen is surely drawn into a specimen supply path, respectively. Numerals 64a, 64b, and 64c denote fourth slits which divide the counter electrode 66, the detecting electrode 67, and the working electrode 65, respectively. Numeral 68 denotes a spacer which covers the working electrode 65, the counter electrode 66, and the detecting electrode 67. Numeral 69 denotes a rectangular cutout part provided in the middle of an entering edge part of the spacer 68 to form a specimen supply path. Numeral 54 denotes a reagent layer which is formed by applying a reagent including enzyme or the like to the working electrode 65, the counter electrode 66, and the detecting electrode 67 by the dripping. Numeral 55 denotes a cover for covering the spacer 68. Numeral 56 denotes an air hole provided in the middle of the cover 55. Numerals 58, 59, and 57 denote correction parts provided at the end parts of respective electrodes, i.e., the working electrode 65, the counter electrode 66, and the detecting electrode 67. Numerals 71, 72, and 73 denote measuring parts which are on the periphery of the cover 55, of parts of the working electrode 65, the counter electrode 66, and the detecting electrode 67, respectively, which are exposed from the cover 55. D denotes a biosensor. Numeral 4115 denotes a measuring device in which the biosensor D is to be inserted. Numeral 4116 denotes an insertion opening of the measuring device 4115 into which the biosensor D is inserted. Numeral 4117 denotes a display part of the measuring device 4115 for displaying a measured result.
FIG. 20 is a diagram in which the sensor sensitivities in blood glucose concentrations of 40-600 mg/dl are compared.
The blood is drawn into a capillary tube, then a reaction between a reaction reagent and glucose in the blood is promoted for about 25 seconds, and thereafter a prescribed voltage is applied between terminals of a working electrode and a counter electrode. The sensor sensitivity here is a current value which is obtained 5 seconds after the application of the prescribed voltage. Since the conventional sensor and the sensor in the embodiment have different electrode materials, an applied voltage is 0.5 V for the conventional carbon paste electrode while it is 0.2 V for the palladium thin film electrode in the embodiment.
Hereinafter, a quantification method of quantifying a substrate and a quantification apparatus for quantifying a substrate, which employ any of the biosensors A, B, C, and C, for which the electrical conductive layers are formed by employing the above-described thin film electrode forming method according to the fifth embodiment will be described. while the biosensor A as described in the first embodiment is used as a biosensor employed in a following description, the biosensor to be used is not restricted thereto.
In the quantification apparatus M1, numerals 115a, 115b, and 115c denote connectors connected to a working electrode 5, a detecting electrode 7, a counter electrode 6 of the biosensor A, respectively, numeral 116a denotes a switch provided between the connector 115c and the ground (which means a constant potential electrodeposition and can be not always “0”. The same goes for in the present specification), numeral 118a denotes a current/voltage conversion circuit which is connected to the connector 115a and converts a current flowing between the working electrode 6 and other electrode into a voltage to be output, numeral 119a denotes an A/D conversion circuit which is connected to the current/voltage conversion circuit 118a and converts a voltage value from the current/voltage conversion circuit 118a into a pulse, numeral 120 denotes a CPU which controls ON/OFF of the switch 116a and calculates the amount of a substrate included in a specimen based on the pulse from the A/D conversion circuit 119a, and numeral 121 denotes a LCD (liquid crystal display) which displays a measured value calculated by the CPU 20.
However, in a case where the current is generated between the counter electrode 6 and the working electrode 5 by the supply of the specimen to the specimen supply path but no current is thereafter generated between the counter electrode 5 and the detecting electrode 7 for the prescribed period of time, the CPU 120 judges that there is a shortage of the specimen amount, and this is displayed on the LCD 121. Even when the specimen is supplemented to the specimen supply path after the LCD 121 once displays that there is a shortage of the specimen supply, the CPU 120 does not start the quantification operation.
As described above, according to the quantification method employing the biosensor in the seventh embodiment of the present invention, when the specimen is drawn into the specimen supply path of the biosensor A, and electrical changes occur between the counter electrode 6 and the working electrode 5 while no electrical change occurs between tre counter electrode 6 and the detecting electrode 7, the quantification apparatus M3 displays on the LCD 121 that there is a shortage of the specimen supply and informs a user of the fact, thereby enhancing the convenience and safety at the measuring.
First, when the biosensor A is connected to the connectors 115a-115c of the quantification apparatus M4, the selector switches 116d and 116c are connected to the current/voltage conversion circuits 118a and 118b under control of the CPU 120, respectively, and a prescribed voltage is applied between the counter electrode 6 and the working electrode 5 as well as between the working electrode 5 and the detecting electrode 7. Currents generated between the counter electrode 6 and the working electrode 5 as well as between the working electrode 5 and the detecting electrode 7 are converted to voltages by the current/voltage conversion circuits 118a and 118b, respectively, and are further converted to pulses by the A/D conversion circuits 119a and 119b.
45. A method of manufacturing a plurality of biosensors for use in quantifying a substrate in a sample liquid, the method comprising the steps of:
providing an insulating support;
providing an electrically conductive layer on a surface of the insulating support;
forming an electrode pattern on the insulating support from the electrically conductive layer, the electrode pattern defining at least a working electrode and a counter electrode for each of a plurality of individual biosensors, wherein the working electrode of an individual biosensor and the counter electrode of an adjacent individual biosensor are not connected to each other;
providing a reagent layer on part of the electrode pattern of the individual biosensors;
providing a spacer layer on the individual biosensors, the spacer layer covering part of the reagent layer;
providing a cover on the spacer layer of the individual biosensors; and
cutting the insulating support, the layers thereon, and the cover to form individual biosensors;
the spacer layer defines a supply path for bringing the sample liquid into contact with the reagent layer;
part of the reagent layer is in the supply path, and the supply path is narrower than the reagent layer; and
a portion of the counter electrode and a portion of the working electrode are in the supply path.
46. The method according to claim 45, further comprising the step of roughening the surface of the insulating support before providing the electrically conductive layer thereon.
47. The method according to claim 46, wherein the surface of the insulating support is roughened by being exposed to an excited gas in a vacuum chamber.
48. The method according to claim 47, wherein the step of roughening the surface of the insulating support and the step of providing the electrically conductive layer thereon are performed in the same vacuum chamber.
49. The method according to claim 45, wherein the insulating support comprises a resin material.
50. The method according to claim 45, wherein the working electrode is surrounded by the counter electrode.
51. The method according to claim 45, wherein a portion of the counter electrode is closer than the working electrode to an inlet of the supply path.
52. The method according to claim 45, wherein the working electrode and the counter electrode are separated by 0.005 mm to 0.3 mm.
53. The method according to claim 45, wherein the electrode pattern further defines a detecting electrode for each of the plurality of individual biosensors, and a portion of the detecting electrode is in the supply path.
54. The method according to claim 53, wherein a portion of the counter electrode is closer than the working electrode to an inlet of the supply path, and the working electrode is closer than the detecting electrode to the inlet of the supply path.
55. The method according to claim 53, wherein the detecting electrode is separated from the closest of the working electrode and the counter electrode by 0.005 mm to 0.3 mm.
56. The method according to claim 45, wherein the electrically conductive layer is formed by vapor deposition or by sputtering evaporation.
57. The method according to claim 45, wherein the electrode pattern is formed by using a laser.
58. The method according to claim 57, wherein a masking plate having a pattern corresponding to the electrode pattern is used to mask the electrically conductive layer when the laser is used to form the electrode pattern.
59. The method according to claim 45, wherein the electrically conductive layer comprises a noble metal selected from the group consisting of palladium, platinum, gold and ruthenium.
60. The method according to claim 45, wherein the electrically conductive layer comprises gold.
61. The method according to claim 45, wherein the electrode pattern has a thickness from 3 nm to 100 nm.
62. The method according to claim 45, wherein the electrode pattern has a thickness from 3 nm to 50 nm.
63. The method according to claim 45, wherein the electrode pattern has a wettability index equal to or greater than 48 dyn/cm.
64. The method according to claim 45, wherein the reagent layer comprises an enzyme.
65. The method according to claim 64, wherein the reagent layer further comprises an electron transfer agent.
66. The method according to claim 65, wherein the reagent layer further comprises a hydrophilic polymer.
67. The method according to claim 45, wherein the individual biosensors comprise an air hole that leads to the supply path.
68. The method according to claim 67, wherein the supply path is sufficiently narrow to draw in the sample liquid by capillary action.
69. The method according to claim 45, wherein a correcting unit stores correction data generated for each production lot of the individual biosensors, which data correspond to characteristics of the biosensors and can be read by a measuring device employing the biosensors.
70. The method according to claim 45, wherein the portion of the counter electrode in the supply path is equal to or larger than the portion of the working electrode in the supply path.
Publication number: 20140308459
Inventors: Shoji Miyazaki (Ehime), Hiroyuki Tokunaga (Ehime), Masaki Fujiwara (Ehime), Eriko Yamanishi (Ehime)
Application Number: 13/861,532
Current U.S. Class: Nonuniform Or Patterned Coating (427/555); Electrical Contact Material (204/192.17); Electrical Product Produced (427/58); Silver, Gold, Platinum, Or Palladium (427/125); Metal Coating (427/123)
International Classification: C12Q 1/00 (20060101);