Silver / silver chloride slurry for CGM biosensor reference electrode and preparation method and application thereof

Abstract

The invention discloses a silver / silver chloride slurry for a CGM biosensor reference electrode and a preparation method and application thereof. The silver / silver chloride slurry comprises the following components by weight: 5-10 parts of a polymer resin, 8-12 parts of an organic solvent, 1-2 parts of a dispersant, 1-2 parts of a curing agent, 10-40 parts of silver chloride particles with a surface modifier, and 40-70 parts of silver powder; the silver powder has a flake powder particle size of 0.3-20um, a ball powder particle size of 0.1-10um, and a dendritic powder particle size of 0.5-15um; the silver chloride particles with a surface modifier have a particle size of 0.1-5um and a surface modifier content of 0.1-3% by weight. The silver / silver chloride slurry for a CGM biosensor reference electrode provided by the invention is particularly suitable for a stainless steel substrate, and the prepared reference electrode has the advantages of excellent adhesion, good bending resistance, low square resistance, good biocompatibility, excellent electrode stability, and the like.

Description

Technical Field

[0001] The invention relates to the preparation of noble metal electronic paste, and in particular to a silver / silver chloride paste for a CGM biosensor reference electrode and a preparation method and application thereof. Background Art

[0002] CGM (Continuous Glucose Monitoring) refers to a monitoring technology that indirectly reflects blood sugar levels by monitoring the glucose concentration in the interstitial fluid of the subcutaneous tissue through a glucose sensor. It can provide continuous, comprehensive and reliable blood sugar information throughout the day, understand the trend of blood sugar fluctuations, and discover hidden hyperglycemia and hypoglycemia that are not easily detected by traditional monitoring methods.

[0003] At present, silver / silver chloride pastes for reference electrodes used to measure EMG, ECG, EEG or EOG signals are often reported. However, silver / silver chloride pastes that can be applied to the stainless steel needle substrate of CGM have not been reported, and there is no special paste with excellent adhesion to stainless steel, good bending resistance, low square resistance, good biocompatibility, and excellent electrode stability. Summary of the invention

[0004] In view of the above problems in the prior art, the present invention provides a silver / silver chloride slurry for a CGM biosensor reference electrode that is particularly suitable for a stainless steel substrate, and a preparation method and application thereof. The reference electrode provided by the present invention has excellent adhesion, good bending resistance, low square resistance, good biocompatibility, excellent electrode stability, etc.

[0005] In order to achieve the above-mentioned object, on the one hand, the present invention provides a silver / silver chloride paste for a reference electrode of a CGM biosensor, wherein the silver / silver chloride paste comprises the following components by weight: 5-10 parts of a polymer resin, 8-12 parts of an organic solvent, 1-2 parts of a dispersant, 1-2 parts of a curing agent, 10-60 parts of silver chloride particles with a surface modifier, and 20-50 parts of silver powder; the silver powder has a flake powder particle size of 0.3-20um, a ball powder particle size of 0.1-10um, and a dendritic powder particle size of 0.5-15um; the silver chloride particles with a surface modifier have a particle size of 0.1-5um, the surface modifier is a fatty acid surface modifier, and the content of the surface modifier is 0.1-3% by weight;

[0006] In the present invention, the polymer resin can be cured with a curing agent under certain conditions, such as curing at 120-150°C for 30 minutes, and the polymer resin is one or more of epoxy resin, acrylic resin, polyurethane, polyester, and chloroacetic resin; the organic solvent is one or more of diethylene glycol ethyl ether acetate, DBE, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, diethylene glycol ethyl ether, and diethylene glycol butyl ether. Preferably, the polymer resin is a combination of thermosetting resin and thermoplastic resin, such as a combination of epoxy resin and polyester polymer resin in a weight ratio of 1:3-4, an acrylic resin and chloroacetic resin, and a polyurethane polymer resin in a weight ratio of 1:1:2. Mixed use improves adhesion and bending resistance to the stainless steel needle base.

[0007] In order to improve the dispersion of each component and avoid the sedimentation and aggregation of the slurry, the dispersant may be one or more of BYK-161, BYK-163, BYK-LPN22836.

[0008] In the present invention, preferably, the curing agent is a blocked isocyanate, which can be commercially obtained, such as Asahi Kasei MF-K60X.

[0009] In the present invention, the inventors found that by adding a surface modifier during grinding, the surface of the silver chloride particles can be provided with a surface modifier, so that the silver chloride powder has good compatibility with the slurry organic carrier, and surprisingly found that it is helpful to improve the adhesion on the stainless steel needle substrate. The preparation method of the silver chloride particles with a surface modifier comprises:

[0010] Step 1: dripping a chloride ion-containing aqueous solution into a silver nitrate aqueous solution until the silver nitrate is completely precipitated, and washing and drying the precipitate to obtain a silver chloride precipitate;

[0011] Step 2: ball milling the silver chloride precipitate to a particle size of 0.1-5 μm, and drying to obtain silver chloride particles with a surface modifier. The ball milling conditions include: using ethanol as a solvent, using zirconium oxide balls, and adding 0.1-3% of a fatty acid surface modifier.

[0012] In the present invention, the surface modifier may be a fatty acid surface modifier. Preferably, the fatty acid surface modifier is one or more of stearic acid, palmitic acid, oleic acid, myristic acid, and lauric acid.

[0013] In the present invention, the chloride ion-containing aqueous solution causes the silver nitrate solution to form silver chloride precipitate. The chloride ion-containing aqueous solution is not particularly limited, and may be, for example, one or more of a sodium chloride aqueous solution, a potassium chloride aqueous solution, and a magnesium chloride aqueous solution.

[0014] On the other hand, the present invention also provides a method for preparing the above-mentioned slurry, which comprises mixing and stirring the components and grinding with three rollers to a fineness of less than 10 um to obtain silver / silver chloride slurry for CGM biosensor reference electrode.

[0015] In a third aspect, the present invention also provides an application of silver / silver chloride slurry for a reference electrode of a CGM biosensor, and the silver / silver chloride slurry for a reference electrode of a CGM biosensor is particularly suitable for use on stainless steel. The stainless steel is not particularly limited, for example, SUS304, SUS316, etc.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The silver / silver chloride slurry for the CGM biosensor reference electrode provided by the present invention is particularly suitable for stainless steel substrates, and the prepared reference electrode has the advantages of excellent adhesion, good bending resistance, low square resistance, good biocompatibility, excellent electrode stability, etc.

[0018] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 This is the SEM of the silver chloride particles with surface modifier of Example 2.

[0021] Figure 2 The current variation curve of the electrode in Example 1 within 15 days.

[0022] Figure 3 The current variation curve of the electrode in Example 2 within 15 days.

[0023] Figure 4 The current variation curve of the electrode in Example 3 within 15 days. DETAILED DESCRIPTION

[0024] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0025] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, the raw materials used are conventional commercially available products.

[0026] Example 1

[0027] 1. Prepare silver chloride powder with surface modifier: first add 1700g of 10% silver nitrate aqueous solution into a stirred reactor, stir at 500rpm, then slowly drop 585g of 10% sodium chloride aqueous solution into the reactor, react at room temperature for 1h, then filter, wash the precipitate with deionized water, and then vacuum dry at 70℃ for 5h; add the dried silver chloride particles into a ball mill, add 0.143g of hard fatty acid surface modifier and 30g of ethanol solvent, use zirconium oxide ball milling beads to mill for 3h, filter out the silver chloride particles, and vacuum dry at 50℃ for 2h to obtain silver chloride powder with an average particle size of 2um and a surface modifier content of 0.1wt%.

[0028] 2. Preparation of silver / silver chloride slurry for CGM biosensor reference electrode: 17.164g epoxy resin and 68.656g polyester polymer resin were dissolved in 107.27g organic solvent diethylene glycol ethyl ether acetate, stirred at 2000rpm, heated at 80℃ for 6h, cooled to room temperature, and then 10.727g dispersant BYK-161, 10.727g curing agent blocked isocyanate Asahi Kasei MF-K60X, and 143g of the above-mentioned silver chloride powder with surface modifier, 715g flaky silver powder (average particle size of 2um) were added in sequence and mixed and stirred, and three-roll milling was performed to a fineness of less than 10um to obtain silver / silver chloride slurry for CGM biosensor reference electrode.

[0029] 3. Preparation of CGM reference electrode and performance test: The above silver / silver chloride slurry was transferred to a stainless steel needle (material: stainless steel SUS304, diameter: 0.3mm) by dip coating process, and dried at 150℃ for 30min to prepare the CGM biosensor reference electrode. The square resistance of the silver / silver chloride slurry after drying was tested by a four-probe tester; the adhesion was tested by 3M600 tape (no shedding is the highest level 5B, 10% shedding is 4B, 30% shedding is 3B, 50% shedding is 2B, 70% shedding is 1B, and all shedding is 0B); the reference electrode was bent 90° for 1min, and whether there were cracks in the bending area (no cracks represent good bending resistance, and cracks represent poor bending resistance); the reference electrode was immersed in glucose solution, and the current change curve of the electrode within 15 days was tested by a potentiometer (Shanghai Chenhua Instrument). The test results are shown in Table 1.

[0030] Example 2

[0031] 1. Prepare silver chloride powder with surface modifier: first add 3400g of 10% silver nitrate aqueous solution into a stirred reactor, stir at 500rpm, then slowly drop 1490g of 10% potassium chloride aqueous solution into the reactor, react at room temperature for 1h, then filter, wash the precipitate with deionized water, and then vacuum dry at 70℃ for 5h; add the dried silver chloride particles into a ball mill, add 2g of stearic acid and 0.86g of palmitic acid surface modifier, 60g of ethanol solvent, use zirconium oxide ball milling beads to mill for 8h, filter out the silver chloride particles, and vacuum dry at 50℃ for 2h to obtain silver chloride powder with an average particle size of 1um and a surface modifier content of 1wt%.

[0032] 2. Preparation of silver / silver chloride slurry for CGM biosensor reference electrode: 17.164g epoxy resin and 57.929g polyurethane polymer resin were dissolved in 107.27g organic solvent DBE, stirred at 2000rpm, heated at 80℃ for 6h, cooled to room temperature, and then 16.091g dispersant BYK-163, 16.091g curing agent blocked isocyanate Asahi Kasei MF-K60X, and 257.46g of the above-mentioned silver chloride powder with surface modifier, 772.37g flaky silver powder (average particle size of 2.5um), 257.46g spherical silver powder (average particle size of 1.5um) (silver chloride powder: silver powder mass ratio of 1:3) were added in sequence and mixed and stirred, and three-roll grinding was performed to a fineness of less than 10um to obtain silver / silver chloride slurry for CGM biosensor reference electrode.

[0033] 3. Preparation of CGM reference electrode and performance test: The above silver / silver chloride paste was transferred to a stainless steel needle (material: stainless steel SUS316, diameter: 0.5mm) by screen printing process, and dried at 140℃ for 30min to prepare the CGM biosensor reference electrode. The square resistance of the silver / silver chloride paste after drying was tested by a four-probe tester; the adhesion was tested by 3M600 tape (no shedding is the highest level 5B, 10% shedding is 4B, 30% shedding is 3B, 50% shedding is 2B, 70% shedding is 1B, and all shedding is 0B); the reference electrode was bent 90° for 1min, and whether there were cracks in the bending area (no cracks represent good bending resistance, and cracks represent poor bending resistance); the reference electrode was immersed in glucose solution, and the current change curve of the electrode within 15 days was tested by a potentiometer (Shanghai Chenhua Instrument). The test results are shown in Table 1.

[0034] Example 3

[0035] 1. Prepare silver chloride powder with surface modifier: first add 6800g of 10% silver nitrate aqueous solution into a stirred reactor, stir at 500rpm, then slowly drop 1900g of 10% magnesium chloride aqueous solution into the reactor, react at room temperature for 1h, then filter, wash the precipitate with deionized water, and then vacuum dry at 70℃ for 5h; add the dried silver chloride particles into a ball mill, add 5.72g of surface modifier (oleic acid, myristic acid and lauric acid in a mass ratio of 1:1:1), 120g of ethanol solvent, use zirconium oxide ball milling beads to ball mill for 6h, filter out the silver chloride particles, and vacuum dry at 50℃ for 2h to obtain silver chloride powder with an average particle size of 1.6um and a surface modifier content of 1wt%.

[0036] 2. Preparation of silver / silver chloride slurry for CGM biosensor reference electrode: 26.818g acrylic resin, 26.818g chloroacetic acid resin, 53.635g polyurethane polymer resin were dissolved in 85.82g organic solvent (4:1 mass ratio of diethylene glycol butyl ether acetate and propylene glycol methyl ether acetate), stirred at 2000rpm, heated at 80℃ for 6h, cooled to room temperature, and then 21.454g dispersant BYK-LPN228 was added. 36, 21.454g of curing agent blocked isocyanate Asahi Kasei MF-K60X, and 429.1g of the above-mentioned silver chloride powder with surface modifier, 400g of flaky silver powder (average particle size of 2.5um), 29.1g of dendritic silver powder (average particle size of 3um) (silver chloride powder: silver powder mass ratio of 1:1) are added in sequence, mixed and stirred, and three-roll milled to a fineness of less than 10um to obtain silver / silver chloride slurry for CGM biosensor reference electrode.

[0037] 3. Preparation of CGM reference electrode and performance test: The above silver / silver chloride paste was transferred to a stainless steel needle (material: stainless steel SUS304, diameter: 3mm) by screen printing process, and dried at 130℃ for 20min to prepare the CGM biosensor reference electrode. The square resistance of the silver / silver chloride paste after drying was tested by a four-probe tester; the adhesion was tested by 3M600 tape (no shedding is the highest level 5B, 10% shedding is 4B, 30% shedding is 3B, 50% shedding is 2B, 70% shedding is 1B, and all shedding is 0B); the reference electrode was bent 90° for 1min, and the bending area was observed to see if there were cracks (no cracks represent good bending resistance, and cracks represent poor bending resistance); the reference electrode was immersed in glucose solution, and the current change curve of the electrode within 15 days was tested by a potentiometer (Shanghai Chenhua Instrument). The test results are shown in Table 1.

[0038] Comparative Example 1

[0039] As in Example 2, the difference is that in the first step, no fatty acid surface modifier is added to the silver chloride powder with surface modifier, while in the second step, an equal amount of fatty acid surface modifier is added when preparing the silver / silver chloride slurry for the reference electrode of the CGM biosensor.

[0040] Comparative Example 2

[0041] As in Example 2, the difference is that when preparing the silver / silver chloride paste for the CGM biosensor reference electrode in step 2, the amount of polymer resin added is adjusted to 75.094 g of thermoplastic polyurethane polymer resin.

[0042] Table 1

[0043]

[0044] From Table 1 and Figure 1-3 As shown, the silver / silver chloride slurry in Examples 1-3 of the present invention has excellent adhesion and bending resistance on the stainless steel needle, so the silver / silver chloride reference electrode layer will not be damaged when used on the CGM sensor, the IT curve is relatively stable, and its electrode stability is also relatively good. The silver / silver chloride slurry in Comparative Example 1-2 has poor adhesion and poor bending resistance on the stainless steel needle. When the CGM sensor is used, the silver / silver chloride reference electrode layer is damaged, the IT curve cannot be tested, and the electrode stability is poor.

[0045] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0046] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0047] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A silver / silver chloride slurry for a CGM biosensor reference electrode, characterized in that: The silver / silver chloride paste comprises the following components by weight: 5-10 parts of polymer resin, 8-12 parts of organic solvent, 1-2 parts of dispersant, 1-2 parts of curing agent, 10-40 parts of silver chloride particles with surface modifier, and 40-70 parts of silver powder; the silver powder has a particle size of 0.3-20um for flake powder, 0.1-10um for spherical powder, and 0.5-15um for dendritic powder; the silver chloride particles with surface modifier have a particle size of 0.1-5um, the surface modifier is a fatty acid surface modifier, and the content of the surface modifier is 0.1-3% by weight; the polymer resin is a combination of epoxy resin and polyester polymer resin in a weight ratio of 1:3-4; the silver / silver chloride paste for reference electrode of CGM biosensor is used on stainless steel; The preparation method of the silver chloride particles with a surface modifier comprises: Step 1: dripping a chloride ion-containing aqueous solution into a silver nitrate aqueous solution until the silver nitrate is completely precipitated, and washing and drying the precipitate to obtain a silver chloride precipitate; Step 2: ball milling the silver chloride precipitate to a particle size of 0.1-5 μm, and drying to obtain silver chloride particles with a surface modifier. The ball milling conditions include: using ethanol as a solvent, using zirconium oxide balls, and adding 0.1-3% of a fatty acid surface modifier; The fatty acid surface modifier is one or more of stearic acid, palmitic acid, oleic acid, myristic acid and lauric acid.

2. The silver / silver chloride slurry for reference electrode of CGM biosensor according to claim 1, characterized in that: The silver / silver chloride paste includes the following components by weight: 8 parts of polymer resin, 10 parts of organic solvent, 1 part of dispersant, 1 part of curing agent, 16 parts of silver chloride particles with surface modifier, and 64 parts of silver powder.

3. The silver / silver chloride slurry for a CGM biosensor reference electrode according to claim 1 or 2, characterized in that: The organic solvent is one or more of diethylene glycol ethyl ether acetate, DBE, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, diethylene glycol ethyl ether, and diethylene glycol butyl ether.

4. The silver / silver chloride slurry for a CGM biosensor reference electrode according to claim 1, characterized in that: The dispersant is one or both of BYK-161 and BYK-163.

5. The silver / silver chloride slurry for a CGM biosensor reference electrode according to claim 1, characterized in that: The curing agent is blocked isocyanate.

6. The silver / silver chloride slurry for a CGM biosensor reference electrode according to claim 1, characterized in that: The chloride ion-containing aqueous solution is one or more of a sodium chloride aqueous solution, a potassium chloride aqueous solution, and a magnesium chloride aqueous solution.

7. The method for preparing the silver / silver chloride slurry for the reference electrode of the CGM biosensor according to any one of claims 1 to 6, characterized in that: The preparation method comprises the steps of mixing and stirring the components and grinding with three rollers until the fineness is less than 10 μm, so as to obtain the silver / silver chloride slurry for the reference electrode of the CGM biosensor.

8. The silver / silver chloride slurry for a CGM biosensor reference electrode according to any one of claims 1 to 6 or the silver / silver chloride slurry for a CGM biosensor reference electrode prepared by the preparation method of claim 7 is used in preparing a CGM biosensor reference electrode, characterized in that: The CGM biosensor reference electrode is applied with silver / silver chloride paste on stainless steel.

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