KR20230043276A - MANUFACTURING METHOD FOR MICRO NEEDLE BIO SENSOR WITH Ag/AgCl REFERENCE ELECTRODE - Google Patents

Abstract

The present invention relates to a microneedle biosensor manufacturing method including an Ag/AgC1 reference electrode. The microneedle biosensor manufacturing method comprises: a working electrode including a first base, a plurality of microneedles, and a first wire; a counter electrode including a second base, a plurality of microneedles, and a second wire; and a reference electrode including a third base, a plurality of microneedles, and a third wire. Therefore, the microneedle biosensor manufacturing method can reduce pain of a user when a microneedle biosensor is worn with minimal invasion.

Description

Microneedle biosensor manufacturing method including Ag/AgCl reference electrode {MANUFACTURING METHOD FOR MICRO NEEDLE BIO SENSOR WITH Ag/AgCl REFERENCE ELECTRODE}

The present invention relates to a method for manufacturing a microneedle biosensor including an Ag/AgCl reference electrode.

Normal human blood glucose levels are within the range of 70 to 130 mg/dL before meals and within the range of 180 mg/dL after meals. If it exceeds this range, it is classified as hyperglycemia, and if it is below the normal range, it is classified as hypoglycemia. Hyperglycemia is highly correlated with diabetes. Diabetes mellitus refers to a group of metabolic diseases in which high blood sugar levels persist for a long period of time.

In order to diagnose diabetes and manage it so that it does not develop into complications, systematic blood glucose measurement and treatment must be performed simultaneously. In general, diabetes is managed by determining an injection amount of insulin according to a patient's blood sugar level and administering insulin at predetermined time intervals. However, since the blood glucose level of each patient and the change in blood sugar according to insulin administration are different for each individual patient, it is difficult to accurately and efficiently determine the insulin dose, administration time, and interval.

To solve this problem, a continuous glucose monitoring (CGM) system may be used. Continuous blood glucose monitoring system was first developed by Medtronic (Minneapolis, MN, USA) and was approved by the US FDA in June 1999. CGM consists of three parts: a blood glucose sensor, a wireless transmitter, and a receiver. The sensor is inserted into the subcutaneous fat to measure sugar in the interstitial fluid. The latest version of the continuous blood glucose monitor shows blood glucose readings in real time, allowing immediate action to be taken.

A conventional continuous blood glucose monitoring device includes a sensor inserted into the body to measure blood glucose, a needle for guiding the sensor to be inserted into the body, and a separate applicator coupling structure to apply the sensor module to the body. The sensor is disposed in the hollow of the syringe needle, pierced subcutaneously by the syringe needle, and inserted into the subcutaneous fat. A sensor is placed in the hollow of the syringe needle. Syringe needles are used up to 21 Gauge in size when blood glucose is detected, and since a sensing strip must be placed in the hollow of the syringe needle, a syringe needle used as a sensor needle in a continuous blood glucose measurement device is generally used with a diameter of 600 nm to 800 nm. When the diameter of the sensor needle is 600 nm to 800 nm, there is a problem of causing pain to the user and giving discomfort during continuous use.

Republic of Korea Patent No. 10-1773583 Republic of Korea Patent Publication No. 10-2017-0038351 Republic of Korea Patent Publication No. 10-2018-0072386 PCT International Publication No. WO 2017-116503

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a method for manufacturing a microneedle biosensor including an Ag/AgCl reference electrode that can reduce pain for a user when worn with minimal invasiveness. .

The present invention,

a working electrode including a first base of a circular thin film, a plurality of microneedles protruding vertically on the first base, and a first wire extending from one end of the circumference of the first base;

A second base of a strip-shaped thin film concentrically with the first base and spaced apart from the circumference of the first base by a set distance and having a 3/4 circumference, a plurality of microneedles protruding vertically on the second base, and the first a counter electrode including a second wiring extending from one end of the second base to be disposed horizontally with the wiring; and

A third base of a strip-shaped thin film of 1/4 circumference, spaced apart from the other end of the second base by a set distance, concentric with the first base and spaced from the circumference of the first base by a set distance, and protruding vertically on the third base In the microneedle biosensor manufacturing method comprising a reference electrode including a plurality of microneedles and a third wiring extending from one end of the third base,

a) forming a mold by forming grooves corresponding to the shapes of microneedles of each of the working electrode, counter electrode, and reference electrode in the solid resin block;

b) imprinting each of the working electrode, counter electrode and reference electrode on the mold using acrylic or PLA;

c) forming a shadow mask corresponding to the patterns of the working electrode, counter electrode, and reference electrode, and forming a metal layer by sputtering an Au or Au+Ti/Cr adhesive layer;

d) forming a passivation layer on the metal layer; and

e) coating Ag/AgCl on the microneedle of the reference electrode,

In the Ag/AgCl coating step, a nucleation time is shorter than that of the working electrode, and a growth time is set longer.

According to an embodiment of the present invention configured as described above, it is possible to provide a method for manufacturing a microneedle biosensor including an Ag/AgCl reference electrode that can reduce user's pain when worn, enable accurate sensing, and is most suitable for the skin surface shape. can

1 is a view showing a microneedle sensor according to an embodiment of the present invention.
2 is a flowchart showing a microneedle sensor manufacturing process.
3 is a flow chart showing a thermal imprinting process in a manufacturing process of a PLA microneedle sensor.
4 is a flow chart showing a UV imprinting process in the manufacturing process of an acrylic microneedle sensor.
FIG. 5 is a diagram explaining step S12 of FIG. 2 .
6 and 7 are diagrams for explaining the Ag/AgCl reference electrode of FIG. 2 .
Figure 8 is a SEM picture taken on the surface of Ag/AgCl.

The present invention will be described in detail with reference to the accompanying drawings. Here, the same reference numerals are used for the same components, and repeated descriptions and detailed descriptions of well-known functions and configurations that may unnecessarily obscure the gist of the present invention are omitted. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shapes and sizes of elements in the drawings may be exaggerated for clarity.

A microneedle biosensor according to an embodiment of the present invention is a minimally invasive microneedle sensor. The present invention relates to a biosensor in which a microneedle invades the skin and contacts a body fluid to monitor a biosignal. The biosensor according to an embodiment of the present invention is intended to measure the blood glucose concentration in the interstitial fluid (ISF) of an invaded host, and is meant to be mounted on the skin surface to continuously measure the blood glucose concentration for a set period of time. Not limited.

1 is a view showing a microneedle sensor according to an embodiment of the present invention. As shown, the microneedle sensor includes a working electrode (WE) 110, a counter electrode (CE) 120, a reference electrode (RE) 130, and an adhesive sheet 200. includes The working electrode 110 includes a circular first base 111, a plurality of microneedles 112 vertically protruding on the first base 111, and a second vertically extending from one end of the first base 111. It includes 1 wire (113). The counter electrode 120 includes a second base 121 concentrically with the first base 111 and formed in a strip shape of a 3/4 circumference spaced apart from the circumference of the first base 111 by a set interval, the second base 121 It includes a plurality of microneedles 122 vertically protruding from the base 121 and a second wire 123 extending from one end of the second base 121 to be disposed horizontally with the first wire 113. . A third base formed in a strip shape of a 1/4 circumference spaced apart from the other end of the second base 121 at a set interval and spaced concentrically with the first base 111 at a set interval from the circumference of the first base 111 131, a plurality of microneedles 132 vertically protruding from the third base 131, extending vertically from one end of the third base 131 to be disposed horizontally with the first wiring 113 It includes a third wiring 133 that

The counter electrode 120 and the reference electrode 130 are spaced apart from the working electrode 110 at set intervals and are arranged to surround the working electrode 110 . The working electrode 110, the counter electrode 120, and the reference electrode 130 are attached to the adhesive sheet 200. In the adhesive sheet 200, it is preferable that an adhesive is applied to one surface of a fiber or polymer sheet. The adhesive sheet 200 preferably has elasticity in itself. In the adhesive sheet 200, the working electrode 110, the counter electrode 220, and the reference electrode 130 are attached to a surface on which an adhesive capable of attaching to the skin is applied. The circular working electrode 110 and the counter electrode 120 and the reference electrode 130 are disposed so as to surround the working electrode 110 and form a strap shape spaced apart from the working electrode 110, and a sheet made of a fiber or polymer material. Since the working electrode 110, the counter electrode 220, and the reference electrode 130 are attached to the skin of the human body, which cannot be structurally flat while securing a sufficient effective area for sensing, each flexibly angles the skin. It can be tilted according to the skin contact surface and attached closely. That is, in the case of a sensor with a flat base, when attached to the skin, which is not flat, as time elapses after attachment, a phenomenon in which the edge is lifted due to resilience occurs, but the microneedle biosensor according to an embodiment of the present invention can solve such a problem. there will be

A microneedle biosensor according to an embodiment of the present invention is formed by sequentially stacking a polymer layer, a metal electrode layer, and a passivation layer.

FIG. 2 is a flowchart illustrating a manufacturing process of the microneedle sensor shown in FIG. 1 . As shown, the microneedle biosensor manufacturing method includes a microneedle manufacturing process (S10) consisting of a mold and imprint process (S11), a support layer formation process (S12), a metallization process (S13), and a passivation process (S14). and a post-treatment process (S20) consisting of Ag/AgCl, Pt-black, Nafion coating, wiring, and packaging processes.

FIG. 3 is a flowchart illustrating a thermal imprint process (S11) of manufacturing a PLA microneedle among the microneedle sensor manufacturing processes of FIG. 2 .

As shown, a mold manufacturing step of forming a groove corresponding to a microneedle in a polytetrafluoroethylene (PTFE) block with a laser (S111), a release agent coating step of coating the mold with a release agent (S112a), Drying the release agent (S113a), forming a PLA layer on a grooved mold and pressing it with ceramic (S114a), baking in a vacuum oven at 200 ° C (S115a), pressing with a press after vacuum off (S116a) consists of PLA (Poly Lactic Acid) microneedle, which is an eco-friendly, non-toxic, biodegradable and biocompatible material, is formed. PLA needles have high elastic modulus and buckling stiffness.

FIG. 4 is a flow chart showing a UV imprinting process for manufacturing acrylic microneedles in the microneedle sensor manufacturing process of FIG. 2 . A mold manufacturing step of forming a groove corresponding to the needle with a laser on a polytetrafluoroethylene (PTFE) block (S111), placing acrylic UV resin on the mold in a vacuum state (S112b), vacuum off After pressing with a press (S113b), a UV curing step (S114b), and a demolding step (S115b) are included. The acrylic microneedle has the advantage of a short manufacturing process of about 5 to 10 minutes, and the acrylic microneedle has the advantage of good adhesion to Au.

2 is a flow chart showing a microneedle sensor manufacturing process. As shown, the microneedle biosensor manufacturing method includes a microneedle manufacturing process (S10) consisting of a mold and imprint process (S11), a metallization process (S12), and a passivation process (S13), Ag/AgCl, Pt- It includes a post-treatment process (S20) consisting of black, Nafion coating and wiring and packaging processes.

FIG. 3 is a flowchart illustrating a thermal imprint process (S11) of manufacturing a PLA microneedle among the microneedle sensor manufacturing processes of FIG. 2 . As shown, a mold manufacturing step (S111) of forming a groove having a shape corresponding to a needle in a polytetrafluoroethylene (PTFE) block with a laser (S111), a release agent coating step (S112a) of coating a release agent on the mold, and a release agent A drying step (S113a), a step of forming a PLA layer on a grooved mold and pressing it with ceramic (S114a), a step of baking in a vacuum oven at 200 ° C (S115a), and a step of pressing with a press after turning off the vacuum (S116a). It consists of PLA (Poly Lactic Acid) microneedle, which is an eco-friendly, non-toxic, biodegradable and biocompatible material, is formed. PLA needles have high elastic modulus and buckling stiffness.

FIG. 4 is a flow chart showing a UV imprinting process for manufacturing acrylic microneedles in the microneedle sensor manufacturing process of FIG. 2 . A mold manufacturing step of forming a groove corresponding to the needle with a laser on a polytetrafluoroethylene (PTFE) block (S111), placing acrylic UV resin on the mold in a vacuum state (S112b), vacuum off After pressing with a press (S113b), a UV curing step (S114b), and a demolding step (S115b) are included. The acrylic microneedle has the advantage of a short manufacturing process of about 5 to 10 minutes, and the acrylic microneedle has the advantage of good adhesion to Au.

FIG. 5 is a diagram explaining a metallization process among the manufacturing processes of the microneedle sensor of FIG. 2 . In the metallization process, a shadow mask corresponding to the pattern of the working electrode 110, counter electrode 120, and reference electrode 130 of FIG. 1 is formed on the microneedle manufactured through the imprint process of FIG. 3 or 4, It is characterized by forming a metal layer by sputtering an Au or Au+Ti/Cr adhesive layer.

6 and 7 are diagrams explaining a process of growing a sensing material on a microneedle. 8 shows a photograph of Ag/AgCl formed on the reference electrode 130 of the microneedle biosensor.

A reference electrode may be formed by drop-casting Ag/AgCl gel on the reference electrode 130 region. The microneedle biosensor according to an embodiment of the present invention is a sensing material for non-enzymatically sensing glucose concentration, and Ag/AgCl is formed flat to accurately apply a reference potential.

That is, it is preferable to grow for a longer time at a lower voltage when growing Ag/AgCl than Pt black.

Claims (3)

a working electrode including a first base of a circular thin film, a plurality of microneedles protruding vertically on the first base, and a first wire extending from one end of the circumference of the first base;
A second base of a strip-shaped thin film concentrically with the first base and spaced apart from the circumference of the first base by a set distance and having a 3/4 circumference, a plurality of microneedles protruding vertically on the second base, and the first a counter electrode including a second wiring extending from one end of the second base to be disposed horizontally with the wiring; and
A third base of a strip-shaped thin film of 1/4 circumference, spaced apart from the other end of the second base by a set distance, concentric with the first base and spaced from the circumference of the first base by a set distance, and protruding vertically on the third base In the microneedle biosensor manufacturing method comprising a reference electrode including a plurality of microneedles and a third wiring extending from one end of the third base,
a) forming a mold by forming grooves corresponding to the shapes of microneedles of each of the working electrode, counter electrode, and reference electrode in the solid resin block;
b) imprinting each of the working electrode, counter electrode and reference electrode on the mold using acrylic or PLA;
c) forming a shadow mask corresponding to the patterns of the working electrode, counter electrode, and reference electrode, and forming a metal layer by sputtering an Au or Au+Ti/Cr adhesive layer;
d) forming a passivation layer on the metal layer; and
e) coating Ag/AgCl on the microneedle of the reference electrode,
In the Ag / AgCl coating step, the nucleation time is shorter than that of the working electrode, and the growth time is set longer. According to claim 1,
A microneedle biosensor manufacturing method comprising an Ag/AgCl reference electrode, characterized in that bottom surfaces of the first base, the second base, and the third base are attached to an adhesive sheet. According to claim 1,
The first wiring extends vertically from one end of the circumference of the first base,
The second wire extends from one end of the second base so as to be disposed horizontally with the first wire,
The method of manufacturing a microneedle biosensor comprising an Ag/AgCl reference electrode, characterized in that the third wiring extends from one end of the third base so as to be disposed horizontally with the first wiring.

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